cvs commit: jakarta-velocity/src/java/org/apache/velocity/util/introspection ClassMap.java

[jv...@locus.apache.org]

jvanzyl     00/11/01 10:17:55

  Added:       src/java/org/apache/velocity/util/introspection
                        ClassMap.java
  Log:
  - missing the ClassMap.java in CVS. whoops.
  
  Revision  Changes    Path
  1.1                  jakarta-velocity/src/java/org/apache/velocity/util/introspection/ClassMap.java
  
  Index: ClassMap.java
  ===================================================================
  package org.apache.velocity.util.introspection;
  
  /*
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2000 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Velocity", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  import java.util.Map;
  import java.util.Hashtable;
  
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  
  public class ClassMap
  {
      /** 
       * Class passed into the constructor used to as
       * the basis for the Method map.
       */
      private Class clazz;
      /**
       * Map of methods that can be accessed directly
       * with a method key.
       */
      private Map directHits = new Hashtable();
      /**
       * Map of nulls that represent methodKeys that
       * will never return a valid method.
       */
      private Map directMisses = new Hashtable();
  
      private MethodMap methodMap = new MethodMap();
  
      /**
       * Standard constructor
       */
      public ClassMap(Class clazz)
      {
          this.clazz = clazz;
          populateDirectHits();
      }
      
      /**
       * Find a Method using the methodKey
       * provided. First try a direct hit, if
       * that doesn't work then we have to do some
       * work to find out if we can return a Method
       * or not. Will implement this ASAP. If we
       * find a valid Method then we can generate
       * a methodKey and add it to the
       * directHits Map.
       */
      public Method findMethod(String name, Object[] params)
      {
          String methodKey = makeMethodKey(name, params);
          
          if (directMisses.containsKey(methodKey))
              return null;
              
          if (directHits.containsKey(methodKey))
              return (Method) directHits.get(methodKey);
          else
          {
              Method method = methodMap.find(name, params);
              
              if (method == null)
                  directMisses.put(methodKey, "");
              else
              {
                  directHits.put(methodKey, method);
                  return method;
              }                
          }
                      
          return null;
      }
      
      /**
       * Populate the Map of direct hits. These
       * are taken from all the public methods
       * that our class provides.
       */
      private void populateDirectHits()
      {
          Method[] methods = clazz.getMethods();
          StringBuffer methodKey;
  
          for (int i = 0; i < methods.length; i++)
          {
              if (Modifier.isPublic(methods[i].getModifiers()))
              {
                  methodMap.add(methods[i]);
                  directHits.put(makeMethodKey(methods[i]), methods[i]);
              }
          }            
      }
  
      /**
       * Make a methodKey for the given method using
       * the concatenation of the name and the
       * types of the method parameters.
       */
      private String makeMethodKey(Method method)
      {
          Class[] parameterTypes = method.getParameterTypes();
          
          StringBuffer methodKey = new StringBuffer().append(method.getName());
          
          for (int j = 0; j < parameterTypes.length; j++)
              methodKey.append(parameterTypes[j].getName());
  
          return methodKey.toString();
      }
  
      private static String makeMethodKey(String method, Object[] params)
      {
          StringBuffer methodKey = new StringBuffer().append(method);
          
          for (int j = 0; j < params.length; j++)
              methodKey.append(params[j].getClass().getName());
  
          return methodKey.toString();
      }
  }