001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.util.io;
016    
017    import java.io.IOException;
018    import java.io.InputStream;
019    import java.io.ObjectInputStream;
020    import java.io.ObjectStreamClass;
021    
022    import org.apache.hivemind.ClassResolver;
023    import org.apache.hivemind.util.Defense;
024    
025    /**
026     * Specialized subclass of {@link java.io.ObjectInputStream}that knows how to
027     * resolve classes with a non-default class loader (represented by an instance
028     * of {@link org.apache.hivemind.ClassResolver}).
029     * 
030     * @author Howard Lewis Ship
031     * @since 3.0
032     */
033    
034    public class ResolvingObjectInputStream extends ObjectInputStream
035    {
036    
037        private ClassResolver _resolver;
038    
039        public ResolvingObjectInputStream(ClassResolver resolver, InputStream input)
040            throws IOException
041        {
042            super(input);
043    
044            Defense.notNull(resolver, "resolver");
045    
046            _resolver = resolver;
047        }
048    
049        /**
050         * Overrides the default implementation to have the resource resolver find
051         * the class.
052         */
053    
054        protected Class resolveClass(ObjectStreamClass v)
055            throws IOException, ClassNotFoundException
056        {
057            return _resolver.findClass(v.getName());
058        }
059    }