/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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.jboss.marshalling;
import java.util.List;
import java.util.ArrayList;
import java.io.IOException;
import java.io.StreamCorruptedException;
/**
* An object table that multiplexes up to 256 class tables. The protocol works by prepending the custom object table
* with an identifier byte.
*/
public class ChainingObjectTable implements ObjectTable {
private static Pair<ObjectTable, Writer> pair(final ObjectTable objectTable, final Writer writer) {
return Pair.create(objectTable, writer);
}
private final List<Pair<ObjectTable, Writer>> writers;
private final ObjectTable[] readers;
/**
* Construct a new instance. The given array may be sparse, but it may not be more than
* 256 elements in length. Object tables are checked in order of increasing array index.
*
* @param objectTables the object tables to delegate to
*/
public ChainingObjectTable(final ObjectTable[] objectTables) {
if (objectTables == null) {
throw new NullPointerException("objectTables is null");
}
readers = objectTables.clone();
if (readers.length > 256) {
throw new IllegalArgumentException("Object table array is too long (limit is 256 elements)");
}
writers = new ArrayList<Pair<ObjectTable, Writer>>();
for (int i = 0; i < readers.length; i++) {
final ObjectTable objectTable = readers[i];
if (objectTable != null) {
final int idx = i;
writers.add(pair(objectTable, new Writer() {
public void writeObject(final Marshaller marshaller, final Object obj) throws IOException {
marshaller.writeByte(idx);
objectTable.getObjectWriter(obj).writeObject(marshaller, obj);
}
}));
}
}
}
/** {@inheritDoc} */
public Writer getObjectWriter(final Object obj) throws IOException {
for (Pair<ObjectTable, Writer> entry : writers) {
final ObjectTable table = entry.getA();
final Writer writer = entry.getB();
if (table.getObjectWriter(obj) != null) {
return writer;
}
}
return null;
}
/** {@inheritDoc} */
public Object readObject(final Unmarshaller unmarshaller) throws IOException, ClassNotFoundException {
final int v = unmarshaller.readByte() & 0xff;
final ObjectTable table = readers[v];
if (table == null) {
throw new StreamCorruptedException(String.format("Unknown object table ID %02x encountered", Integer.valueOf(v)));
}
return table.readObject(unmarshaller);
}
}