/*
 * Copyright 2001,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.jexl.util.introspection;

import java.lang.reflect.Method;

import org.apache.commons.logging.Log;


/**
 * This basic function of this class is to return a Method
 * object for a particular class given the name of a method
 * and the parameters to the method in the form of an Object[]
 *
 * The first time the Introspector sees a 
 * class it creates a class method map for the
 * class in question. Basically the class method map
 * is a Hashtable where Method objects are keyed by a
 * concatenation of the method name and the names of
 * classes that make up the parameters.
 *
 * For example, a method with the following signature:
 *
 * public void method(String a, StringBuffer b)
 *
 * would be mapped by the key:
 *
 * "method" + "java.lang.String" + "java.lang.StringBuffer"
 *
 * This mapping is performed for all the methods in a class
 * and stored for 
 * @since 1.0
 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
 * @author <a href="mailto:bob@werken.com">Bob McWhirter</a>
 * @author <a href="mailto:szegedia@freemail.hu">Attila Szegedi</a>
 * @author <a href="mailto:paulo.gaspar@krankikom.de">Paulo Gaspar</a>
 * @version $Id$
 */
public class Introspector extends IntrospectorBase
{
    /**
     *  define a public string so that it can be looked for
     *  if interested
     */

    public static final String CACHEDUMP_MSG = 
        "Introspector : detected classloader change. Dumping cache.";

    /**
     *  our engine runtime services
     */
    private final Log rlog;

    /**
     *  Recieves our RuntimeServices object
     */
    public Introspector(Log logger)
    {
        this.rlog = logger;
    }
   
    /**
     * Gets the method defined by <code>name</code> and
     * <code>params</code> for the Class <code>c</code>.
     *
     * @param c Class in which the method search is taking place
     * @param name Name of the method being searched for
     * @param params An array of Objects (not Classes) that describe the
     *               the parameters
     *
     * @return The desired Method object.
     */
    public Method getMethod(Class c, String name, Object[] params)
        throws Exception
    {
        /*
         *  just delegate to the base class
         */

        try
        {
            return super.getMethod( c, name, params );
        }
        catch( MethodMap.AmbiguousException ae )
        {
            /*
             *  whoops.  Ambiguous.  Make a nice log message and return null...
             */

            String msg = "Introspection Error : Ambiguous method invocation "
                + name + "( ";

            for (int i = 0; i < params.length; i++)
            {
                if ( i > 0)
                    msg += ", ";
                
                msg += params[i].getClass().getName();
            }
            
            msg = msg + ") for class " + c;
            
            rlog.error( msg );
        }

        return null;
    }

    /**
     * Clears the classmap and classname
     * caches, and logs that we did so
     */
    protected void clearCache()
    {
        super.clearCache();
        rlog.info( CACHEDUMP_MSG );
    }
}

@@ -3163,23 +3163,46 @@
   String
+Buffer
  msg = 
+new StringBuffer(
 %22Introsp
@@ -3245,16 +3245,17 @@
 cation %22
+)
 %0A       
@@ -3267,21 +3267,34 @@
     
-+ name + 
+.append(name).append(
 %22( %22
+)
 ;%0A%0A 
@@ -3413,16 +3413,21 @@
  msg
- += 
+.append(
 %22, %22
+)
 ;%0A  
@@ -3464,12 +3464,16 @@
  msg
- += 
+.append(
 para
@@ -3498,16 +3498,17 @@
 etName()
+)
 ;%0A      
@@ -3547,17 +3547,16 @@
  msg
- = msg + 
+.append(
 %22) f
@@ -3569,12 +3569,29 @@
 ss %22
- + c
+).append(c.getName())
 ;%0A  
@@ -3628,16 +3628,27 @@
 ror( msg
+.toString()
  );%0A    

Use StringBuffer rather than looping string concats