001: /*
002: * The Apache Software License, Version 1.1
003: *
004: * Copyright (c) 1999 The Apache Software Foundation. All rights
005: * reserved.
006: *
007: * Redistribution and use in source and binary forms, with or without
008: * modification, are permitted provided that the following conditions
009: * are met:
010: *
011: * 1. Redistributions of source code must retain the above copyright
012: * notice, this list of conditions and the following disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The end-user documentation included with the redistribution, if
020: * any, must include the following acknowlegement:
021: * "This product includes software developed by the
022: * Apache Software Foundation (http://www.apache.org/)."
023: * Alternately, this acknowlegement may appear in the software itself,
024: * if and wherever such third-party acknowlegements normally appear.
025: *
026: * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
027: * Foundation" must not be used to endorse or promote products derived
028: * from this software without prior written permission. For written
029: * permission, please contact apache@apache.org.
030: *
031: * 5. Products derived from this software may not be called "Apache"
032: * nor may "Apache" appear in their names without prior written
033: * permission of the Apache Group.
034: *
035: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
036: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
037: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
038: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
039: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
040: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
041: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
042: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
043: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
044: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
045: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
046: * SUCH DAMAGE.
047: * ====================================================================
048: *
049: * This software consists of voluntary contributions made by many
050: * individuals on behalf of the Apache Software Foundation. For more
051: * information on the Apache Software Foundation, please see
052: * <http://www.apache.org/>.
053: *
054: */
055:
056: package org.jbpm.jpdl.el.impl;
057:
058: import java.lang.reflect.InvocationTargetException;
059: import java.lang.reflect.Method;
060: import java.util.Iterator;
061: import java.util.List;
062:
063: import org.jbpm.jpdl.el.ELException;
064: import org.jbpm.jpdl.el.FunctionMapper;
065: import org.jbpm.jpdl.el.VariableResolver;
066:
067: /**
068: *
069: * <p>Represents a function call.</p>
070: *
071: * @author Shawn Bayern (in the style of Nathan's other classes)
072: **/
073:
074: public class FunctionInvocation extends Expression {
075: //-------------------------------------
076: // Properties
077: //-------------------------------------
078: // property index
079:
080: private String functionName;
081: private List argumentList;
082:
083: public String getFunctionName() {
084: return functionName;
085: }
086:
087: public void setFunctionName(String f) {
088: functionName = f;
089: }
090:
091: public List getArgumentList() {
092: return argumentList;
093: }
094:
095: public void setArgumentList(List l) {
096: argumentList = l;
097: }
098:
099: //-------------------------------------
100: /**
101: * Constructor
102: **/
103: public FunctionInvocation(String functionName, List argumentList) {
104: this .functionName = functionName;
105: this .argumentList = argumentList;
106: }
107:
108: //-------------------------------------
109: // Expression methods
110: //-------------------------------------
111: /**
112: * Returns the expression in the expression language syntax
113: **/
114: public String getExpressionString() {
115: StringBuffer b = new StringBuffer();
116: b.append(functionName);
117: b.append("(");
118: Iterator i = argumentList.iterator();
119: while (i.hasNext()) {
120: b.append(((Expression) i.next()).getExpressionString());
121: if (i.hasNext())
122: b.append(", ");
123: }
124: b.append(")");
125: return b.toString();
126: }
127:
128: //-------------------------------------
129: /**
130: *
131: * Evaluates by looking up the name in the VariableResolver
132: **/
133: public Object evaluate(VariableResolver pResolver,
134: FunctionMapper functions, Logger pLogger)
135: throws ELException {
136:
137: // if the Map is null, then the function is invalid
138: if (functions == null)
139: pLogger.logError(Constants.UNKNOWN_FUNCTION, functionName);
140:
141: // normalize function name
142: String prefix = null;
143: String localName = null;
144: int index = functionName.indexOf(':');
145: if (index == -1) {
146: prefix = "";
147: localName = functionName;
148: } else {
149: prefix = functionName.substring(0, index);
150: localName = functionName.substring(index + 1);
151: }
152:
153: // ensure that the function's name is mapped
154: Method target = (Method) functions.resolveFunction(prefix,
155: localName);
156: if (target == null)
157: pLogger.logError(Constants.UNKNOWN_FUNCTION, functionName);
158:
159: // ensure that the number of arguments matches the number of parameters
160: Class[] params = target.getParameterTypes();
161: if (params.length != argumentList.size())
162: pLogger.logError(
163: Constants.INAPPROPRIATE_FUNCTION_ARG_COUNT,
164: functionName, new Integer(params.length),
165: new Integer(argumentList.size()));
166:
167: // now, walk through each parameter, evaluating and casting its argument
168: Object[] arguments = new Object[argumentList.size()];
169: for (int i = 0; i < params.length; i++) {
170: // evaluate
171: arguments[i] = ((Expression) argumentList.get(i)).evaluate(
172: pResolver, functions, pLogger);
173: // coerce
174: arguments[i] = Coercions.coerce(arguments[i], params[i],
175: pLogger);
176: }
177:
178: // finally, invoke the target method, which we know to be static
179: try {
180: return (target.invoke(null, arguments));
181: } catch (InvocationTargetException ex) {
182: pLogger.logError(Constants.FUNCTION_INVOCATION_ERROR, ex
183: .getTargetException(), functionName);
184: return null;
185: } catch (Exception ex) {
186: pLogger.logError(Constants.FUNCTION_INVOCATION_ERROR, ex,
187: functionName);
188: return null;
189: }
190: }
191:
192: //-------------------------------------
193: }
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