Source Code Cross Referenced for JavaExtensionLibrary.java in  » XML » saxonb » net » sf » saxon » functions » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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Java Source Code / Java Documentation » XML » saxonb » net.sf.saxon.functions 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


0001:        package net.sf.saxon.functions;
0002:
0003:        import net.sf.saxon.Configuration;
0004:        import net.sf.saxon.expr.Expression;
0005:        import net.sf.saxon.expr.StaticContext;
0006:        import net.sf.saxon.expr.XPathContext;
0007:        import net.sf.saxon.om.*;
0008:        import net.sf.saxon.trans.StaticError;
0009:        import net.sf.saxon.trans.XPathException;
0010:        import net.sf.saxon.type.ExternalObjectType;
0011:        import net.sf.saxon.type.ItemType;
0012:        import net.sf.saxon.type.Type;
0013:        import net.sf.saxon.type.TypeHierarchy;
0014:        import net.sf.saxon.value.*;
0015:
0016:        import java.io.PrintStream;
0017:        import java.lang.reflect.*;
0018:        import java.math.BigDecimal;
0019:        import java.math.BigInteger;
0020:        import java.net.URI;
0021:        import java.net.URL;
0022:        import java.util.ArrayList;
0023:        import java.util.Date;
0024:        import java.util.HashMap;
0025:        import java.util.List;
0026:
0027:        /**
0028:         * The JavaExtensionLibrary is a FunctionLibrary that binds XPath function calls to
0029:         * calls on Java methods (or constructors, or fields). It performs a mapping from
0030:         * the namespace URI of the function to the Java class (the mapping is partly table
0031:         * driven and partly algorithmic), and maps the local name of the function to the
0032:         * Java method, constructor, or field within the class. If the Java methods are
0033:         * polymorphic, then it tries to select the appropriate method based on the static types
0034:         * of the supplied arguments. Binding is done entirely at XPath compilation time.
0035:         */
0036:
0037:        public class JavaExtensionLibrary implements  FunctionLibrary {
0038:
0039:            private Configuration config;
0040:
0041:            // HashMap containing URI->Class mappings. This includes conventional
0042:            // URIs such as the Saxon and EXSLT namespaces, and mapping defined by
0043:            // the user using saxon:script
0044:
0045:            private HashMap explicitMappings = new HashMap(10);
0046:
0047:            // Output destination for debug messages. At present this cannot be configured.
0048:
0049:            private transient PrintStream diag = System.err;
0050:
0051:            /**
0052:             * Construct a JavaExtensionLibrary and establish the default uri->class mappings.
0053:             * @param config The Saxon configuration
0054:             */
0055:
0056:            public JavaExtensionLibrary(Configuration config) {
0057:                this .config = config;
0058:                setDefaultURIMappings();
0059:            }
0060:
0061:            /**
0062:             * Define initial mappings of "well known" namespace URIs to Java classes (this covers
0063:             * the Saxon and EXSLT extensions). The method is protected so it can be overridden in
0064:             * a subclass.
0065:             */
0066:            protected void setDefaultURIMappings() {
0067:                declareJavaClass(NamespaceConstant.SAXON,
0068:                        net.sf.saxon.functions.Extensions.class);
0069:                declareJavaClass(NamespaceConstant.EXSLT_COMMON,
0070:                        net.sf.saxon.exslt.Common.class);
0071:                declareJavaClass(NamespaceConstant.EXSLT_SETS,
0072:                        net.sf.saxon.exslt.Sets.class);
0073:                declareJavaClass(NamespaceConstant.EXSLT_MATH,
0074:                        net.sf.saxon.exslt.Math.class);
0075:                declareJavaClass(NamespaceConstant.EXSLT_DATES_AND_TIMES,
0076:                        net.sf.saxon.exslt.Date.class);
0077:                declareJavaClass(NamespaceConstant.EXSLT_RANDOM,
0078:                        net.sf.saxon.exslt.Random.class);
0079:            }
0080:
0081:            /**
0082:             * Declare a mapping from a specific namespace URI to a Java class
0083:             * @param uri the namespace URI of the function name
0084:             * @param theClass the Java class that implements the functions in this namespace
0085:             */
0086:
0087:            public void declareJavaClass(String uri, Class theClass) {
0088:                explicitMappings.put(uri, theClass);
0089:            }
0090:
0091:            /**
0092:             * Test whether an extension function with a given name and arity is available. This supports
0093:             * the function-available() function in XSLT. This method may be called either at compile time
0094:             * or at run time.
0095:             * @param fingerprint The code that identifies the function name in the NamePool. This must
0096:             * match the supplied URI and local name.
0097:             * @param uri  The URI of the function name
0098:             * @param local  The local part of the function name
0099:             * @param arity The number of arguments. This is set to -1 in the case of the single-argument
0100:             * function-available() function; in this case the method should return true if there is some
0101:             * matching extension function, regardless of its arity.
0102:             */
0103:
0104:            public boolean isAvailable(int fingerprint, String uri,
0105:                    String local, int arity) {
0106:                if (!config.isAllowExternalFunctions()) {
0107:                    return false;
0108:                }
0109:                Class reqClass;
0110:                try {
0111:                    reqClass = getExternalJavaClass(uri);
0112:                    if (reqClass == null) {
0113:                        return false;
0114:                    }
0115:                } catch (Exception err) {
0116:                    return false;
0117:                }
0118:                int significantArgs;
0119:
0120:                Class theClass = reqClass;
0121:
0122:                // if the method name is "new", look for a matching constructor
0123:
0124:                if ("new".equals(local)) {
0125:
0126:                    int mod = theClass.getModifiers();
0127:                    if (Modifier.isAbstract(mod)) {
0128:                        return false;
0129:                    } else if (Modifier.isInterface(mod)) {
0130:                        return false;
0131:                    } else if (Modifier.isPrivate(mod)) {
0132:                        return false;
0133:                    } else if (Modifier.isProtected(mod)) {
0134:                        return false;
0135:                    }
0136:
0137:                    if (arity == -1)
0138:                        return true;
0139:
0140:                    Constructor[] constructors = theClass.getConstructors();
0141:                    for (int c = 0; c < constructors.length; c++) {
0142:                        Constructor theConstructor = constructors[c];
0143:                        if (theConstructor.getParameterTypes().length == arity) {
0144:                            return true;
0145:                        }
0146:                    }
0147:                    return false;
0148:                } else {
0149:
0150:                    // convert any hyphens in the name, camelCasing the following character
0151:
0152:                    String name = toCamelCase(local, false, diag);
0153:
0154:                    // look through the methods of this class to find one that matches the local name
0155:
0156:                    Method[] methods = theClass.getMethods();
0157:                    for (int m = 0; m < methods.length; m++) {
0158:
0159:                        Method theMethod = methods[m];
0160:                        if (theMethod.getName().equals(name)
0161:                                && Modifier.isPublic(theMethod.getModifiers())) {
0162:                            if (arity == -1)
0163:                                return true;
0164:                            Class[] theParameterTypes = theMethod
0165:                                    .getParameterTypes();
0166:                            boolean isStatic = Modifier.isStatic(theMethod
0167:                                    .getModifiers());
0168:
0169:                            // if the method is not static, the first supplied argument is the instance, so
0170:                            // discount it
0171:
0172:                            significantArgs = (isStatic ? arity : arity - 1);
0173:
0174:                            if (significantArgs >= 0) {
0175:
0176:                                if (theParameterTypes.length == significantArgs
0177:                                        && (significantArgs == 0 || theParameterTypes[0] != XPathContext.class)) {
0178:                                    return true;
0179:                                }
0180:
0181:                                // we allow the method to have an extra parameter if the first parameter is XPathContext
0182:
0183:                                if (theParameterTypes.length == significantArgs + 1
0184:                                        && theParameterTypes[0] == XPathContext.class) {
0185:                                    return true;
0186:                                }
0187:                            }
0188:                        }
0189:                    }
0190:
0191:                    // look through the fields of this class to find those that matches the local name
0192:
0193:                    Field[] fields = theClass.getFields();
0194:                    for (int m = 0; m < fields.length; m++) {
0195:
0196:                        Field theField = fields[m];
0197:                        if (theField.getName().equals(name)
0198:                                && Modifier.isPublic(theField.getModifiers())) {
0199:                            if (arity == -1)
0200:                                return true;
0201:                            boolean isStatic = Modifier.isStatic(theField
0202:                                    .getModifiers());
0203:
0204:                            // if the field is not static, the first supplied argument is the instance, so
0205:                            // discount it
0206:
0207:                            significantArgs = (isStatic ? arity : arity - 1);
0208:
0209:                            if (significantArgs == 0) {
0210:                                return true;
0211:                            }
0212:                        }
0213:                    }
0214:
0215:                    return false;
0216:                }
0217:
0218:            }
0219:
0220:            /**
0221:             * Bind an extension function, given the URI and local parts of the function name,
0222:             * and the list of expressions supplied as arguments. This method is called at compile
0223:             * time.
0224:             * @param nameCode The namepool code of the function name. This must match the supplied
0225:             * URI and local name.
0226:             * @param uri  The URI of the function name
0227:             * @param local  The local part of the function name
0228:             * @param staticArgs  The expressions supplied statically in the function call. The intention is
0229:             * that the static type of the arguments (obtainable via getItemType() and getCardinality()) may
0230:             * be used as part of the binding algorithm.
0231:             * @return An object representing the extension function to be called, if one is found;
0232:             * null if no extension function was found matching the required name, arity, or signature.
0233:             */
0234:
0235:            public Expression bind(int nameCode, String uri, String local,
0236:                    Expression[] staticArgs) throws XPathException {
0237:
0238:                boolean debug = config.isTraceExternalFunctions();
0239:                if (!config.isAllowExternalFunctions()) {
0240:                    if (debug) {
0241:                        diag
0242:                                .println("Calls to extension functions have been disabled");
0243:                    }
0244:                    return null;
0245:                }
0246:
0247:                Class reqClass;
0248:                Exception theException = null;
0249:                ArrayList candidateMethods = new ArrayList(10);
0250:                Class resultClass = null;
0251:
0252:                try {
0253:                    reqClass = getExternalJavaClass(uri);
0254:                    if (reqClass == null) {
0255:                        return null;
0256:                    }
0257:                } catch (Exception err) {
0258:                    throw new StaticError("Cannot load external Java class",
0259:                            err);
0260:                }
0261:
0262:                if (debug) {
0263:                    diag.println("Looking for method " + local
0264:                            + " in Java class " + reqClass);
0265:                    diag.println("Number of actual arguments = "
0266:                            + staticArgs.length);
0267:                }
0268:
0269:                int numArgs = staticArgs.length;
0270:                int significantArgs;
0271:
0272:                Class theClass = reqClass;
0273:
0274:                // if the method name is "new", look for a matching constructor
0275:
0276:                if ("new".equals(local)) {
0277:
0278:                    if (debug) {
0279:                        diag.println("Looking for a constructor");
0280:                    }
0281:
0282:                    int mod = theClass.getModifiers();
0283:                    if (Modifier.isAbstract(mod)) {
0284:                        theException = new StaticError("Class " + theClass
0285:                                + " is abstract");
0286:                    } else if (Modifier.isInterface(mod)) {
0287:                        theException = new StaticError(theClass
0288:                                + " is an interface");
0289:                    } else if (Modifier.isPrivate(mod)) {
0290:                        theException = new StaticError("Class " + theClass
0291:                                + " is private");
0292:                    } else if (Modifier.isProtected(mod)) {
0293:                        theException = new StaticError("Class " + theClass
0294:                                + " is protected");
0295:                    }
0296:
0297:                    if (theException != null) {
0298:                        if (debug) {
0299:                            diag.println("Cannot construct an instance: "
0300:                                    + theException.getMessage());
0301:                        }
0302:                        return null;
0303:                    }
0304:
0305:                    Constructor[] constructors = theClass.getConstructors();
0306:                    for (int c = 0; c < constructors.length; c++) {
0307:                        Constructor theConstructor = constructors[c];
0308:                        if (debug) {
0309:                            diag.println("Found a constructor with "
0310:                                    + theConstructor.getParameterTypes().length
0311:                                    + " arguments");
0312:                        }
0313:                        if (theConstructor.getParameterTypes().length == numArgs) {
0314:                            candidateMethods.add(theConstructor);
0315:                        }
0316:                    }
0317:                    if (candidateMethods.size() == 0) {
0318:                        theException = new StaticError("No constructor with "
0319:                                + numArgs
0320:                                + (numArgs == 1 ? " parameter" : " parameters")
0321:                                + " found in class " + theClass.getName());
0322:                        if (debug) {
0323:                            diag.println(theException.getMessage());
0324:                        }
0325:                        return null;
0326:                    }
0327:                } else {
0328:
0329:                    // convert any hyphens in the name, camelCasing the following character
0330:
0331:                    String name = toCamelCase(local, debug, diag);
0332:
0333:                    // look through the methods of this class to find one that matches the local name
0334:
0335:                    Method[] methods = theClass.getMethods();
0336:                    boolean consistentReturnType = true;
0337:                    for (int m = 0; m < methods.length; m++) {
0338:
0339:                        Method theMethod = methods[m];
0340:
0341:                        if (debug) {
0342:                            if (theMethod.getName().equals(name)) {
0343:                                diag.println("Trying method "
0344:                                        + theMethod.getName()
0345:                                        + ": name matches");
0346:                                if (!Modifier
0347:                                        .isPublic(theMethod.getModifiers())) {
0348:                                    diag
0349:                                            .println(" -- but the method is not public");
0350:                                }
0351:                            } else {
0352:                                diag.println("Trying method "
0353:                                        + theMethod.getName()
0354:                                        + ": name does not match");
0355:                            }
0356:                        }
0357:
0358:                        if (theMethod.getName().equals(name)
0359:                                && Modifier.isPublic(theMethod.getModifiers())) {
0360:
0361:                            if (consistentReturnType) {
0362:                                if (resultClass == null) {
0363:                                    resultClass = theMethod.getReturnType();
0364:                                } else {
0365:                                    consistentReturnType = (theMethod
0366:                                            .getReturnType() == resultClass);
0367:                                }
0368:                            }
0369:                            Class[] theParameterTypes = theMethod
0370:                                    .getParameterTypes();
0371:                            boolean isStatic = Modifier.isStatic(theMethod
0372:                                    .getModifiers());
0373:
0374:                            // if the method is not static, the first supplied argument is the instance, so
0375:                            // discount it
0376:
0377:                            if (debug) {
0378:                                diag.println("Method is "
0379:                                        + (isStatic ? "" : "not ") + "static");
0380:                            }
0381:
0382:                            significantArgs = (isStatic ? numArgs : numArgs - 1);
0383:
0384:                            if (significantArgs >= 0) {
0385:
0386:                                if (debug) {
0387:                                    diag
0388:                                            .println("Method has "
0389:                                                    + theParameterTypes.length
0390:                                                    + " argument"
0391:                                                    + (theParameterTypes.length == 1 ? ""
0392:                                                            : "s")
0393:                                                    + "; expecting "
0394:                                                    + significantArgs);
0395:                                }
0396:
0397:                                if (theParameterTypes.length == significantArgs
0398:                                        && (significantArgs == 0 || theParameterTypes[0] != XPathContext.class)) {
0399:                                    if (debug) {
0400:                                        diag
0401:                                                .println("Found a candidate method:");
0402:                                        diag.println("    " + theMethod);
0403:                                    }
0404:                                    candidateMethods.add(theMethod);
0405:                                }
0406:
0407:                                // we allow the method to have an extra parameter if the first parameter is XPathContext
0408:
0409:                                if (theParameterTypes.length == significantArgs + 1
0410:                                        && theParameterTypes[0] == XPathContext.class) {
0411:                                    if (debug) {
0412:                                        diag
0413:                                                .println("Method is a candidate because first argument is XPathContext");
0414:                                    }
0415:                                    candidateMethods.add(theMethod);
0416:                                }
0417:                            }
0418:                        }
0419:                    }
0420:
0421:                    // Code added by GS -- start
0422:
0423:                    // look through the fields of this class to find those that matches the local name
0424:
0425:                    Field[] fields = theClass.getFields();
0426:                    for (int m = 0; m < fields.length; m++) {
0427:
0428:                        Field theField = fields[m];
0429:
0430:                        if (debug) {
0431:                            if (theField.getName().equals(name)) {
0432:                                diag
0433:                                        .println("Trying field "
0434:                                                + theField.getName()
0435:                                                + ": name matches");
0436:                                if (!Modifier.isPublic(theField.getModifiers())) {
0437:                                    diag
0438:                                            .println(" -- but the field is not public");
0439:                                }
0440:                            } else {
0441:                                diag.println("Trying field "
0442:                                        + theField.getName()
0443:                                        + ": name does not match");
0444:                            }
0445:                        }
0446:
0447:                        if (theField.getName().equals(name)
0448:                                && Modifier.isPublic(theField.getModifiers())) {
0449:                            if (consistentReturnType) {
0450:                                if (resultClass == null) {
0451:                                    resultClass = theField.getType();
0452:                                } else {
0453:                                    consistentReturnType = (theField.getType() == resultClass);
0454:                                }
0455:                            }
0456:                            boolean isStatic = Modifier.isStatic(theField
0457:                                    .getModifiers());
0458:
0459:                            // if the field is not static, the first supplied argument is the instance, so
0460:                            // discount it
0461:
0462:                            if (debug) {
0463:                                diag.println("Field is "
0464:                                        + (isStatic ? "" : "not ") + "static");
0465:                            }
0466:
0467:                            significantArgs = (isStatic ? numArgs : numArgs - 1);
0468:
0469:                            if (significantArgs == 0) {
0470:                                if (debug) {
0471:                                    diag.println("Found a candidate field:");
0472:                                    diag.println("    " + theField);
0473:                                }
0474:                                candidateMethods.add(theField);
0475:                            }
0476:                        }
0477:                    }
0478:
0479:                    // End of code added by GS
0480:
0481:                    // No method found?
0482:
0483:                    if (candidateMethods.size() == 0) {
0484:                        theException = new StaticError(
0485:                                "No method or field matching "
0486:                                        + name
0487:                                        + " with "
0488:                                        + numArgs
0489:                                        + (numArgs == 1 ? " parameter"
0490:                                                : " parameters")
0491:                                        + " found in class "
0492:                                        + theClass.getName());
0493:                        if (debug) {
0494:                            diag.println(theException.getMessage());
0495:                        }
0496:                        return null;
0497:                    }
0498:                }
0499:                if (candidateMethods.size() == 0) {
0500:                    if (debug) {
0501:                        diag
0502:                                .println("There is no suitable method matching the arguments of function "
0503:                                        + local);
0504:                    }
0505:                    return null;
0506:                }
0507:                AccessibleObject method = getBestFit(candidateMethods,
0508:                        staticArgs, theClass);
0509:                if (method == null) {
0510:                    if (candidateMethods.size() > 1) {
0511:                        // There was more than one candidate method, and we can't decide which to use.
0512:                        // This may be because insufficient type information is available at this stage.
0513:                        // Return an UnresolvedExtensionFunction, and try to resolve it later when more
0514:                        // type information is known.
0515:                        return new UnresolvedExtensionFunction(nameCode,
0516:                                theClass, candidateMethods, staticArgs);
0517:                    }
0518:                    return null;
0519:                } else {
0520:                    ExtensionFunctionFactory factory = config
0521:                            .getExtensionFunctionFactory();
0522:                    return factory.makeExtensionFunctionCall(nameCode,
0523:                            theClass, method, staticArgs);
0524:                }
0525:            }
0526:
0527:            /**
0528:             * Get the best fit amongst all the candidate methods, constructors, or fields, based on the static types
0529:             * of the supplied arguments
0530:             * @param candidateMethods a list of all the methods, fields, and constructors that match the extension
0531:             * function call in name and arity (but not necessarily in the types of the arguments)
0532:             * @param args the expressions supplied as arguments.F
0533:             * @return the result is either a Method or a Constructor or a Field, or null if no unique best fit
0534:             * method could be found.
0535:             */
0536:
0537:            private AccessibleObject getBestFit(List candidateMethods,
0538:                    Expression[] args, Class theClass) {
0539:                boolean debug = config.isTraceExternalFunctions();
0540:                int candidates = candidateMethods.size();
0541:
0542:                if (candidates == 1) {
0543:                    // short cut: there is only one candidate method
0544:                    return (AccessibleObject) candidateMethods.get(0);
0545:
0546:                } else {
0547:                    // choose the best fit method or constructor or field
0548:                    // for each pair of candidate methods, eliminate either or both of the pair
0549:                    // if one argument is less-preferred
0550:
0551:                    if (debug) {
0552:                        diag.println("Finding best fit method with arguments:");
0553:                        for (int v = 0; v < args.length; v++) {
0554:                            args[v].display(10, config.getNamePool(), diag);
0555:                        }
0556:                    }
0557:
0558:                    boolean eliminated[] = new boolean[candidates];
0559:                    for (int i = 0; i < candidates; i++) {
0560:                        eliminated[i] = false;
0561:                    }
0562:
0563:                    if (debug) {
0564:                        for (int i = 0; i < candidates; i++) {
0565:                            int[] pref_i = getConversionPreferences(args,
0566:                                    (AccessibleObject) candidateMethods.get(i),
0567:                                    theClass);
0568:                            diag.println("Trying option " + i + ": "
0569:                                    + candidateMethods.get(i).toString());
0570:                            if (pref_i == null) {
0571:                                diag
0572:                                        .println("Arguments cannot be converted to required types");
0573:                            } else {
0574:                                String prefs = "[";
0575:                                for (int p = 0; p < pref_i.length; p++) {
0576:                                    if (p != 0)
0577:                                        prefs += ", ";
0578:                                    prefs += pref_i[p];
0579:                                }
0580:                                prefs += "]";
0581:                                diag.println("Conversion preferences are "
0582:                                        + prefs);
0583:                            }
0584:                        }
0585:                    }
0586:
0587:                    for (int i = 0; i < candidates; i++) {
0588:                        int[] pref_i = getConversionPreferences(args,
0589:                                (AccessibleObject) candidateMethods.get(i),
0590:                                theClass);
0591:
0592:                        if (pref_i == null) {
0593:                            eliminated[i] = true;
0594:                        }
0595:                        if (!eliminated[i]) {
0596:                            for (int j = i + 1; j < candidates; j++) {
0597:                                if (!eliminated[j]) {
0598:                                    int[] pref_j = getConversionPreferences(
0599:                                            args,
0600:                                            (AccessibleObject) candidateMethods
0601:                                                    .get(j), theClass);
0602:                                    if (pref_j == null) {
0603:                                        eliminated[j] = true;
0604:                                    } else {
0605:                                        for (int k = 0; k < pref_j.length; k++) {
0606:                                            if (pref_i[k] > pref_j[k]
0607:                                                    && !eliminated[i]) { // high number means less preferred
0608:                                                eliminated[i] = true;
0609:                                                if (debug) {
0610:                                                    diag
0611:                                                            .println("Eliminating option "
0612:                                                                    + i);
0613:                                                }
0614:                                            }
0615:                                            if (pref_i[k] < pref_j[k]
0616:                                                    && !eliminated[j]) {
0617:                                                eliminated[j] = true;
0618:                                                if (debug) {
0619:                                                    diag
0620:                                                            .println("Eliminating option "
0621:                                                                    + j);
0622:                                                }
0623:                                            }
0624:                                        }
0625:                                    }
0626:                                }
0627:                            }
0628:                        }
0629:                    }
0630:
0631:                    int remaining = 0;
0632:                    AccessibleObject theMethod = null;
0633:                    for (int r = 0; r < candidates; r++) {
0634:                        if (!eliminated[r]) {
0635:                            theMethod = (AccessibleObject) candidateMethods
0636:                                    .get(r);
0637:                            remaining++;
0638:                        }
0639:                    }
0640:
0641:                    if (debug) {
0642:                        diag.println("Number of candidate methods remaining: "
0643:                                + remaining);
0644:                    }
0645:
0646:                    if (remaining == 0) {
0647:                        if (debug) {
0648:                            diag
0649:                                    .println("There are "
0650:                                            + candidates
0651:                                            + " candidate Java methods matching the function name, but none is a unique best match");
0652:                        }
0653:                        return null;
0654:                    }
0655:
0656:                    if (remaining > 1) {
0657:                        if (debug) {
0658:                            diag
0659:                                    .println("There are several Java methods that match the function name equally well");
0660:                        }
0661:                        return null;
0662:                    }
0663:
0664:                    return theMethod;
0665:                }
0666:            }
0667:
0668:            /**
0669:             * Convert a name to camelCase (by removing hyphens and changing the following
0670:             * letter to capitals)
0671:             * @param name the name to be converted to camelCase
0672:             * @param debug true if tracing is required
0673:             * @return the camelCased name
0674:             */
0675:
0676:            private static String toCamelCase(String name, boolean debug,
0677:                    PrintStream diag) {
0678:                if (name.indexOf('-') >= 0) {
0679:                    FastStringBuffer buff = new FastStringBuffer(name.length());
0680:                    boolean afterHyphen = false;
0681:                    for (int n = 0; n < name.length(); n++) {
0682:                        char c = name.charAt(n);
0683:                        if (c == '-') {
0684:                            afterHyphen = true;
0685:                        } else {
0686:                            if (afterHyphen) {
0687:                                buff.append(Character.toUpperCase(c));
0688:                            } else {
0689:                                buff.append(c);
0690:                            }
0691:                            afterHyphen = false;
0692:                        }
0693:                    }
0694:                    name = buff.toString();
0695:                    if (debug) {
0696:                        diag.println("Seeking a method with adjusted name "
0697:                                + name);
0698:                    }
0699:                }
0700:                return name;
0701:            }
0702:
0703:            /**
0704:             * Get an array of integers representing the conversion distances of each "real" argument
0705:             * to a given method
0706:             * @param args: the actual expressions supplied in the function call
0707:             * @param method: the method or constructor.
0708:             * @return an array of integers, one for each argument, indicating the conversion
0709:             * distances. A high number indicates low preference. If any of the arguments cannot
0710:             * be converted to the corresponding type defined in the method signature, return null.
0711:             */
0712:
0713:            private int[] getConversionPreferences(Expression[] args,
0714:                    AccessibleObject method, Class theClass) {
0715:
0716:                Class[] params;
0717:                int firstArg;
0718:                TypeHierarchy th = config.getNamePool().getTypeHierarchy();
0719:                if (method instanceof  Constructor) {
0720:                    firstArg = 0;
0721:                    params = ((Constructor) method).getParameterTypes();
0722:                } else if (method instanceof  Method) {
0723:                    boolean isStatic = Modifier.isStatic(((Method) method)
0724:                            .getModifiers());
0725:                    firstArg = (isStatic ? 0 : 1);
0726:                    params = ((Method) method).getParameterTypes();
0727:                } else if (method instanceof  Field) {
0728:                    boolean isStatic = Modifier.isStatic(((Field) method)
0729:                            .getModifiers());
0730:                    firstArg = (isStatic ? 0 : 1);
0731:                    params = NO_PARAMS;
0732:                } else {
0733:                    throw new AssertionError("property " + method
0734:                            + " was neither constructor, method, nor field");
0735:                }
0736:
0737:                int noOfArgs = args.length;
0738:                int preferences[] = new int[noOfArgs];
0739:                int firstParam = 0;
0740:
0741:                if (params.length > 0 && params[0] == XPathContext.class) {
0742:                    firstParam = 1;
0743:                }
0744:                for (int i = firstArg; i < noOfArgs; i++) {
0745:                    preferences[i] = getConversionPreference(th, args[i],
0746:                            params[i + firstParam - firstArg]);
0747:                    if (preferences[i] == -1) {
0748:                        return null;
0749:                    }
0750:                }
0751:
0752:                if (firstArg == 1) {
0753:                    preferences[0] = getConversionPreference(th, args[0],
0754:                            theClass);
0755:                    if (preferences[0] == -1) {
0756:                        return null;
0757:                    }
0758:                }
0759:
0760:                return preferences;
0761:            }
0762:
0763:            /**
0764:             * Get the conversion preference from a given XPath type to a given Java class
0765:             * @param arg the supplied XPath expression (the static type of this expression
0766:             * is used as input to the algorithm)
0767:             * @param required the Java class of the relevant argument of the Java method
0768:             * @return the conversion preference. A high number indicates a low preference;
0769:             * -1 indicates that conversion is not possible.
0770:             */
0771:
0772:            private int getConversionPreference(TypeHierarchy th,
0773:                    Expression arg, Class required) {
0774:                ItemType itemType = arg.getItemType(th);
0775:                int cardinality = arg.getCardinality();
0776:                if (required == Object.class) {
0777:                    return 100;
0778:                } else if (Cardinality.allowsMany(cardinality)) {
0779:                    if (required.isAssignableFrom(SequenceIterator.class)) {
0780:                        return 20;
0781:                    } else if (required.isAssignableFrom(Value.class)) {
0782:                        return 21;
0783:                    } else if (Collection.class.isAssignableFrom(required)) {
0784:                        return 22;
0785:                    } else if (required.isArray()) {
0786:                        return 24;
0787:                        // sort out at run-time whether the component type of the array is actually suitable
0788:                    } else {
0789:                        return 80; // conversion possible only if external object model supports it
0790:                    }
0791:                } else {
0792:                    if (Type.isNodeType(itemType)) {
0793:                        if (required.isAssignableFrom(NodeInfo.class)) {
0794:                            return 20;
0795:                        } else if (required
0796:                                .isAssignableFrom(DocumentInfo.class)) {
0797:                            return 21;
0798:                        } else {
0799:                            return 80;
0800:                        }
0801:                    } else if (itemType instanceof  ExternalObjectType) {
0802:                        Class ext = ((ExternalObjectType) itemType)
0803:                                .getJavaClass();
0804:                        if (required.isAssignableFrom(ext)) {
0805:                            return 10;
0806:                        } else {
0807:                            return -1;
0808:                        }
0809:                    } else {
0810:                        int primitiveType = itemType.getPrimitiveType();
0811:                        return atomicConversionPreference(primitiveType,
0812:                                required);
0813:                    }
0814:                }
0815:            }
0816:
0817:            private static final Class[] NO_PARAMS = new Class[0];
0818:
0819:            /**
0820:             * Get the conversion preference from an XPath primitive atomic type to a Java class
0821:             * @param primitiveType integer code identifying the XPath primitive type, for example
0822:             * {@link net.sf.saxon.type.Type#INTEGER} or {@link net.sf.saxon.type.Type#STRING}
0823:             * @param required The Java Class named in the method signature
0824:             * @return an integer indicating the relative preference for converting this primitive type
0825:             * to this Java class. A high number indicates a low preference. All values are in the range
0826:             * 50 to 100. For example, the conversion of an XPath String to {@link net.sf.saxon.value.StringValue} is 50, while
0827:             * XPath String to {@link java.lang.String} is 51. The value -1 indicates that the conversion is not allowed.
0828:             */
0829:
0830:            protected int atomicConversionPreference(int primitiveType,
0831:                    Class required) {
0832:                if (required == Object.class)
0833:                    return 100;
0834:                switch (primitiveType) {
0835:                case Type.STRING:
0836:                    if (required.isAssignableFrom(StringValue.class))
0837:                        return 50;
0838:                    if (required == String.class)
0839:                        return 51;
0840:                    if (required == CharSequence.class)
0841:                        return 51;
0842:                    return -1;
0843:                case Type.DOUBLE:
0844:                    if (required.isAssignableFrom(DoubleValue.class))
0845:                        return 50;
0846:                    if (required == double.class)
0847:                        return 50;
0848:                    if (required == Double.class)
0849:                        return 51;
0850:                    return -1;
0851:                case Type.FLOAT:
0852:                    if (required.isAssignableFrom(FloatValue.class))
0853:                        return 50;
0854:                    if (required == float.class)
0855:                        return 50;
0856:                    if (required == Float.class)
0857:                        return 51;
0858:                    if (required == double.class)
0859:                        return 52;
0860:                    if (required == Double.class)
0861:                        return 53;
0862:                    return -1;
0863:                case Type.DECIMAL:
0864:                    if (required.isAssignableFrom(DecimalValue.class))
0865:                        return 50;
0866:                    if (required == BigDecimal.class)
0867:                        return 50;
0868:                    if (required == double.class)
0869:                        return 51;
0870:                    if (required == Double.class)
0871:                        return 52;
0872:                    if (required == float.class)
0873:                        return 53;
0874:                    if (required == Float.class)
0875:                        return 54;
0876:                    return -1;
0877:                case Type.INTEGER:
0878:                    if (required.isAssignableFrom(IntegerValue.class))
0879:                        return 50;
0880:                    if (required == BigInteger.class)
0881:                        return 51;
0882:                    if (required == BigDecimal.class)
0883:                        return 52;
0884:                    if (required == long.class)
0885:                        return 53;
0886:                    if (required == Long.class)
0887:                        return 54;
0888:                    if (required == int.class)
0889:                        return 55;
0890:                    if (required == Integer.class)
0891:                        return 56;
0892:                    if (required == short.class)
0893:                        return 57;
0894:                    if (required == Short.class)
0895:                        return 58;
0896:                    if (required == byte.class)
0897:                        return 59;
0898:                    if (required == Byte.class)
0899:                        return 60;
0900:                    if (required == double.class)
0901:                        return 61;
0902:                    if (required == Double.class)
0903:                        return 62;
0904:                    if (required == float.class)
0905:                        return 63;
0906:                    if (required == Float.class)
0907:                        return 64;
0908:                    return -1;
0909:                case Type.BOOLEAN:
0910:                    if (required.isAssignableFrom(BooleanValue.class))
0911:                        return 50;
0912:                    if (required == boolean.class)
0913:                        return 51;
0914:                    if (required == Boolean.class)
0915:                        return 52;
0916:                    return -1;
0917:                case Type.DATE:
0918:                case Type.G_DAY:
0919:                case Type.G_MONTH_DAY:
0920:                case Type.G_MONTH:
0921:                case Type.G_YEAR_MONTH:
0922:                case Type.G_YEAR:
0923:                    if (required.isAssignableFrom(DateValue.class))
0924:                        return 50;
0925:                    if (required.isAssignableFrom(Date.class))
0926:                        return 51;
0927:                    return -1;
0928:                case Type.DATE_TIME:
0929:                    if (required.isAssignableFrom(DateTimeValue.class))
0930:                        return 50;
0931:                    if (required.isAssignableFrom(Date.class))
0932:                        return 51;
0933:                    return -1;
0934:                case Type.TIME:
0935:                    if (required.isAssignableFrom(TimeValue.class))
0936:                        return 50;
0937:                    return -1;
0938:                case Type.DURATION:
0939:                case Type.YEAR_MONTH_DURATION:
0940:                case Type.DAY_TIME_DURATION:
0941:                    if (required.isAssignableFrom(DurationValue.class))
0942:                        return 50;
0943:                    return -1;
0944:                case Type.ANY_URI:
0945:                    if (required.isAssignableFrom(AnyURIValue.class))
0946:                        return 50;
0947:                    if (required == URI.class)
0948:                        return 51;
0949:                    if (required == URL.class)
0950:                        return 52;
0951:                    if (required == String.class)
0952:                        return 53;
0953:                    if (required == CharSequence.class)
0954:                        return 53;
0955:                    return -1;
0956:                case Type.QNAME:
0957:                    if (required.isAssignableFrom(QNameValue.class))
0958:                        return 50;
0959:                    //if (required.isAssignableFrom(QName.class)) return 51;
0960:                    // TODO: reinstate above line under JDK 1.5
0961:                    if (required.getClass().getName().equals(
0962:                            "javax.xml.namespace.QName"))
0963:                        return 51;
0964:                    return -1;
0965:                case Type.BASE64_BINARY:
0966:                    if (required.isAssignableFrom(Base64BinaryValue.class))
0967:                        return 50;
0968:                    return -1;
0969:                case Type.HEX_BINARY:
0970:                    if (required.isAssignableFrom(HexBinaryValue.class))
0971:                        return 50;
0972:                    return -1;
0973:                case Type.UNTYPED_ATOMIC:
0974:                    return 50;
0975:                default:
0976:                    return -1;
0977:                }
0978:            }
0979:
0980:            /**
0981:             * Get an external Java class corresponding to a given namespace prefix, if there is
0982:             * one.
0983:             * @param uri The namespace URI corresponding to the prefix used in the function call.
0984:             * @return the Java class name if a suitable class exists, otherwise return null.
0985:             */
0986:
0987:            private Class getExternalJavaClass(String uri) {
0988:
0989:                // First see if an explicit mapping has been registered for this URI
0990:
0991:                Class c = (Class) explicitMappings.get(uri);
0992:                if (c != null) {
0993:                    return c;
0994:                }
0995:
0996:                // Failing that, try to identify a class directly from the URI
0997:
0998:                try {
0999:
1000:                    // support the URN format java:full.class.Name
1001:
1002:                    if (uri.startsWith("java:")) {
1003:                        return config.getClass(uri.substring(5), config
1004:                                .isTraceExternalFunctions(), null);
1005:                    }
1006:
1007:                    // extract the class name as anything in the URI after the last "/"
1008:                    // if there is one, or the whole class name otherwise
1009:
1010:                    int slash = uri.lastIndexOf('/');
1011:                    if (slash < 0) {
1012:                        return config.getClass(uri, config
1013:                                .isTraceExternalFunctions(), null);
1014:                    } else if (slash == uri.length() - 1) {
1015:                        return null;
1016:                    } else {
1017:                        return config.getClass(uri.substring(slash + 1), config
1018:                                .isTraceExternalFunctions(), null);
1019:                    }
1020:                } catch (XPathException err) {
1021:                    return null;
1022:                }
1023:            }
1024:
1025:            /**
1026:             * Inner class representing an unresolved extension function call. This arises when there is insufficient
1027:             * static type information available at the time the function call is parsed to determine which of several
1028:             * candidate Java methods to invoke. The function call cannot be executed; it must be resolved to an
1029:             * actual Java method during the analysis phase.
1030:             */
1031:
1032:            private class UnresolvedExtensionFunction extends
1033:                    CompileTimeFunction {
1034:
1035:                List candidateMethods;
1036:                int nameCode;
1037:                Class theClass;
1038:
1039:                public UnresolvedExtensionFunction(int nameCode,
1040:                        Class theClass, List candidateMethods,
1041:                        Expression[] staticArgs) {
1042:                    setArguments(staticArgs);
1043:                    this .nameCode = nameCode;
1044:                    this .theClass = theClass;
1045:                    this .candidateMethods = candidateMethods;
1046:                }
1047:
1048:                /**
1049:                 * Type-check the expression.
1050:                 */
1051:
1052:                public Expression typeCheck(StaticContext env,
1053:                        ItemType contextItemType) throws XPathException {
1054:                    for (int i = 0; i < argument.length; i++) {
1055:                        Expression exp = argument[i].typeCheck(env,
1056:                                contextItemType);
1057:                        if (exp != argument[i]) {
1058:                            adoptChildExpression(exp);
1059:                            argument[i] = exp;
1060:                        }
1061:                    }
1062:                    AccessibleObject method = getBestFit(candidateMethods,
1063:                            argument, theClass);
1064:                    if (method == null) {
1065:                        StaticError err = new StaticError(
1066:                                "There is more than one method matching the function call "
1067:                                        + config.getNamePool().getDisplayName(
1068:                                                nameCode)
1069:                                        + ", and there is insufficient type information to determine which one should be used");
1070:                        err.setLocator(this );
1071:                        throw err;
1072:                    } else {
1073:                        ExtensionFunctionFactory factory = config
1074:                                .getExtensionFunctionFactory();
1075:                        return factory.makeExtensionFunctionCall(nameCode,
1076:                                theClass, method, argument);
1077:                    }
1078:                }
1079:            }
1080:
1081:            /**
1082:             * This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows
1083:             * new functions to be added, then additions to this copy will not affect the original, or
1084:             * vice versa.
1085:             *
1086:             * @return a copy of this function library. This must be an instance of the original class.
1087:             */
1088:
1089:            public FunctionLibrary copy() {
1090:                JavaExtensionLibrary jel = new JavaExtensionLibrary(config);
1091:                jel.explicitMappings = new HashMap(explicitMappings);
1092:                jel.diag = diag;
1093:                return jel;
1094:            }
1095:
1096:        }
1097:
1098:        //
1099:        // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
1100:        // you may not use this file except in compliance with the License. You may obtain a copy of the
1101:        // License at http://www.mozilla.org/MPL/
1102:        //
1103:        // Software distributed under the License is distributed on an "AS IS" basis,
1104:        // WITHOUT WARRANTY OF ANY KIND, either express or implied.
1105:        // See the License for the specific language governing rights and limitations under the License.
1106:        //
1107:        // The Original Code is: all this file.
1108:        //
1109:        // The Initial Developer of the Original Code is Michael H. Kay.
1110:        //
1111:        // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
1112:        //
1113:        // Contributor(s): none.
1114:        //
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