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/*  Copyright 1999 Vince Via [email protected]
    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 com.viaoa.remote.multiplexer.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.io.StreamCorruptedException;
import java.net.Socket;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Used internally for remoting objects between clients and servers.
 * Since we are controlling both sides of the comm, we are able to reduce a lot
 * of the overhead - ex: sending header information and class descriptions,  
 * @author vvia
 */
public class RemoteObjectInputStream extends ObjectInputStream {
    private ConcurrentHashMap hmClassDesc;

    public RemoteObjectInputStream(Socket socket, 
            ConcurrentHashMap hmClassDesc) throws IOException {
        super(socket.getInputStream());

        this.hmClassDesc = hmClassDesc;
    }
    
    // 20141121 used by OAObjectSerializer to embed compressed objects
    public RemoteObjectInputStream(InputStream is, RemoteObjectInputStream rois) throws IOException {
        super(is);
        if (rois != null) {
            this.hmClassDesc = rois.hmClassDesc;
        }
    }
    
    
    @Override
    protected void readStreamHeader() throws IOException, StreamCorruptedException {
    }

    @Override
    protected ObjectStreamClass readClassDescriptor() throws IOException, ClassNotFoundException {
        ObjectStreamClass osc;
        int id = readInt();
        if (id >= 0) {
            osc = hmClassDesc.get(id);
        }
        else {
            id = readInt();
            osc = super.readClassDescriptor();
            if (id >= 0) {
                hmClassDesc.put(id, osc);
            }
        }
        return osc;
    }

    // faster then using readUTF
    public String readAsciiString() throws IOException {
        short x = readShort();
        if (x == 0) return null;
        byte[] bs = new byte[x];
        readFully(bs);
        String s = new String(bs, 0); // ascii only
        return s;
    }
}