org.jboss.marshalling.ChainingObjectTable Maven / Gradle / Ivy
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* Copyright 2008, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
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 interface Pair {
X getX();
Y getY();
}
private static Pair pair(final ObjectTable objectTable, final Writer writer) {
return new Pair() {
public ObjectTable getX() {
return objectTable;
}
public Writer getY() {
return writer;
}
};
}
private final List> 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>();
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 entry : writers) {
final ObjectTable table = entry.getX();
final Writer writer = entry.getY();
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);
}
}