tapestry/tapestry-framework/src/java/org/apache/tapestry/util/io/ResolvingObjectInputStream.java

// Copyright 2004, 2005 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.tapestry.util.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;

import org.apache.hivemind.ClassResolver;
import org.apache.hivemind.util.Defense;

/**
 * Specialized subclass of {@link java.io.ObjectInputStream}that knows how to
 * resolve classes with a non-default class loader (represented by an instance
 * of {@link org.apache.hivemind.ClassResolver}).
 * 
 * @author Howard Lewis Ship
 * @since 3.0
 */

public class ResolvingObjectInputStream extends ObjectInputStream
{

    private ClassResolver _resolver;

    public ResolvingObjectInputStream(ClassResolver resolver, InputStream input)
        throws IOException
    {
        super(input);

        Defense.notNull(resolver, "resolver");

        _resolver = resolver;
    }

    /**
     * Overrides the default implementation to have the resource resolver find
     * the class.
     */

    protected Class resolveClass(ObjectStreamClass v)
        throws IOException, ClassNotFoundException
    {
        return _resolver.findClass(v.getName());
    }
}