001: package murlen.util.fscript.introspection;
002:
003: /*
004: * The Apache Software License, Version 1.1
005: *
006: * Copyright (c) 2001 The Apache Software Foundation. All rights
007: * reserved.
008: *
009: * Redistribution and use in source and binary forms, with or without
010: * modification, are permitted provided that the following conditions
011: * are met:
012: *
013: * 1. Redistributions of source code must retain the above copyright
014: * notice, this list of conditions and the following disclaimer.
015: *
016: * 2. Redistributions in binary form must reproduce the above copyright
017: * notice, this list of conditions and the following disclaimer in
018: * the documentation and/or other materials provided with the
019: * distribution.
020: *
021: * 3. The end-user documentation included with the redistribution, if
022: * any, must include the following acknowlegement:
023: * "This product includes software developed by the
024: * Apache Software Foundation (http://www.apache.org/)."
025: * Alternately, this acknowlegement may appear in the software itself,
026: * if and wherever such third-party acknowlegements normally appear.
027: *
028: * 4. The names "The Jakarta Project", "Velocity", and "Apache Software
029: * Foundation" must not be used to endorse or promote products derived
030: * from this software without prior written permission. For written
031: * permission, please contact apache@apache.org.
032: *
033: * 5. Products derived from this software may not be called "Apache"
034: * nor may "Apache" appear in their names without prior written
035: * permission of the Apache Group.
036: *
037: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
038: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
039: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
040: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
041: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
042: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
043: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
044: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
045: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
046: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
047: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
048: * SUCH DAMAGE.
049: * ====================================================================
050: *
051: * This software consists of voluntary contributions made by many
052: * individuals on behalf of the Apache Software Foundation. For more
053: * information on the Apache Software Foundation, please see
054: * <http://www.apache.org/>.
055: */
056:
057: import java.lang.reflect.Method;
058:
059: /**
060: * This basic function of this class is to return a Method
061: * object for a particular class given the name of a method
062: * and the parameters to the method in the form of an Object[]
063: *
064: * The first time the Introspector sees a
065: * class it creates a class method map for the
066: * class in question. Basically the class method map
067: * is a Hastable where Method objects are keyed by a
068: * concatenation of the method name and the names of
069: * classes that make up the parameters.
070: *
071: * For example, a method with the following signature:
072: *
073: * public void method(String a, StringBuffer b)
074: *
075: * would be mapped by the key:
076: *
077: * "method" + "java.lang.String" + "java.lang.StringBuffer"
078: *
079: * This mapping is performed for all the methods in a class
080: * and stored for
081: * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
082: * @author <a href="mailto:bob@werken.com">Bob McWhirter</a>
083: * @author <a href="mailto:szegedia@freemail.hu">Attila Szegedi</a>
084: * @author <a href="mailto:paulo.gaspar@krankikom.de">Paulo Gaspar</a>
085: * @version $Id: Introspector.java,v 1.1.1.1 2004/07/28 01:28:04 murlen Exp $
086: */
087: public class Introspector extends IntrospectorBase {
088: /**
089: * define a public string so that it can be looked for
090: * if interested
091: */
092:
093: public final static String CACHEDUMP_MSG = "Introspector : detected classloader change. Dumping cache.";
094:
095: /**
096: * Gets the method defined by <code>name</code> and
097: * <code>params</code> for the Class <code>c</code>.
098: *
099: * @param c Class in which the method search is taking place
100: * @param name Name of the method being searched for
101: * @param params An array of Objects (not Classes) that describe the
102: * the parameters
103: *
104: * @return The desired Method object.
105: */
106: public Method getMethod(Class c, String name, Object[] params)
107: throws Exception {
108: /*
109: * just delegate to the base class
110: */
111:
112: try {
113: return super .getMethod(c, name, params);
114: } catch (MethodMap.AmbiguousException ae) {
115: /*
116: * whoops. Ambiguous. Make a nice log message and return null...
117: */
118:
119: String msg = "Introspection Error : Ambiguous method invocation "
120: + name + "( ";
121:
122: for (int i = 0; i < params.length; i++) {
123: if (i > 0)
124: msg = msg + ", ";
125:
126: msg = msg + params[i].getClass().getName();
127: }
128:
129: msg = msg + ") for class " + c;
130: }
131:
132: return null;
133: }
134:
135: /**
136: * Clears the classmap and classname
137: * caches, and logs that we did so
138: */
139: protected void clearCache() {
140: super.clearCache();
141: }
142: }
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