| package org.apache.velocity.util.introspection; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| import java.lang.reflect.Method; |
| |
| /** |
| * Lookup a a Method object for a particular class given the name of a method |
| * and its parameters. |
| * |
| * 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. |
| * @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> |
| * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a> |
| * @version $Id$ |
| */ |
| public abstract class IntrospectorBase |
| implements IntrospectorCacheListener |
| { |
| /** The Introspector Cache */ |
| private final IntrospectorCache introspectorCache; |
| |
| /** |
| * C'tor. |
| */ |
| protected IntrospectorBase() |
| { |
| introspectorCache = new IntrospectorCacheImpl(); // TODO: Load that from properties. |
| introspectorCache.addListener(this); |
| } |
| |
| /** |
| * 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. |
| * @throws IllegalArgumentException When the parameters passed in can not be used for introspection. |
| * @throws MethodMap.AmbiguousException When the method map contains more than one match for the requested signature. |
| */ |
| public Method getMethod(final Class c, final String name, final Object[] params) |
| throws IllegalArgumentException,MethodMap.AmbiguousException |
| { |
| if (c == null) |
| { |
| throw new IllegalArgumentException ("class object is null!"); |
| } |
| |
| if (params == null) |
| { |
| throw new IllegalArgumentException("params object is null!"); |
| } |
| |
| ClassMap classMap = null; |
| |
| IntrospectorCache ic = getIntrospectorCache(); |
| |
| synchronized(ic) |
| { |
| classMap = ic.get(c); |
| |
| if (classMap == null) |
| { |
| classMap = ic.put(c); |
| } |
| } |
| |
| return classMap.findMethod(name, params); |
| } |
| |
| /** |
| * Return the internal IntrospectorCache object. |
| * |
| * @return The internal IntrospectorCache object. |
| */ |
| protected IntrospectorCache getIntrospectorCache() |
| { |
| return introspectorCache; |
| } |
| |
| /** |
| * Clears the internal cache. |
| * |
| * @deprecated Use getIntrospectorCache().clear(); |
| */ |
| protected void clearCache() |
| { |
| getIntrospectorCache().clear(); |
| } |
| |
| /** |
| * Creates a class map for specific class and registers it in the |
| * cache. Also adds the qualified name to the name->class map |
| * for later Classloader change detection. |
| * |
| * @param c The class for which the class map gets generated. |
| * @return A ClassMap object. |
| * |
| * @deprecated Use getIntrospectorCache().put(c); |
| */ |
| protected ClassMap createClassMap(final Class c) |
| { |
| return getIntrospectorCache().put(c); |
| } |
| |
| /** |
| * Lookup a given Class object in the cache. If it does not exist, |
| * check whether this is due to a class change and purge the caches |
| * eventually. |
| * |
| * @param c The class to look up. |
| * @return A ClassMap object or null if it does not exist in the cache. |
| * |
| * @deprecated Use getIntrospectorCache().get(c); |
| */ |
| protected ClassMap lookupClassMap(final Class c) |
| { |
| return getIntrospectorCache().get(c); |
| } |
| |
| /** |
| * @see IntrospectorCacheListener#triggerClear() |
| */ |
| public void triggerClear() |
| { |
| } |
| |
| /** |
| * @see IntrospectorCacheListener#triggerGet(Class, ClassMap) |
| */ |
| public void triggerGet(Class c, ClassMap classMap) |
| { |
| } |
| |
| /** |
| * @see IntrospectorCacheListener#triggerPut(Class, ClassMap) |
| */ |
| public void triggerPut(Class c, ClassMap classMap) |
| { |
| } |
| } |