/*
* @(#)$Id$
*
* Copyright 2006-2008 Makoto YUI
*
* 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.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.xquery.dm.value.sequence;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import javax.annotation.Nonnull;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import xbird.util.io.FastByteArrayInputStream;
import xbird.util.io.FastByteArrayOutputStream;
import xbird.util.io.IOUtils;
import xbird.util.lang.PrintUtils;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.coder.XQEventDecoder;
import xbird.xquery.dm.coder.XQEventEncoder;
import xbird.xquery.dm.value.AbstractSequence;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.IFocus;
import xbird.xquery.type.Type;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class EncodedSequence extends AbstractSequence<Item> implements Externalizable {
private static final Log LOG = LogFactory.getLog(EncodedSequence.class);
private byte[] encodedSequence = null;
@Nonnull
private transient Sequence actualSequence;
@Nonnull
private Type type;
public EncodedSequence(Sequence delegate, DynamicContext dynEnv) {
super(dynEnv);
this.actualSequence = delegate;
this.type = delegate.getType();
}
public Type getType() {
return type;
}
public boolean next(IFocus<Item> focus) throws XQueryException {
return actualSequence.next(focus);
}
public synchronized void doEncode() throws IOException {
if(encodedSequence != null) {
final FastByteArrayOutputStream bufOut = new FastByteArrayOutputStream(16384);
final ObjectOutputStream objOut = new ObjectOutputStream(bufOut);
final XQEventEncoder encoder = new XQEventEncoder(objOut);
try {
encoder.emit(actualSequence);
objOut.flush();
} catch (XQueryException xqe) {
throw new IOException(PrintUtils.prettyPrintStackTrace(xqe));
} catch (Throwable e) {
LOG.fatal(e);
throw new IOException(PrintUtils.prettyPrintStackTrace(e));
}
this.encodedSequence = bufOut.toByteArray();
}
}
private static Sequence decode(final byte[] b) throws IOException {
FastByteArrayInputStream inputBuf = new FastByteArrayInputStream(b);
ObjectInputStream objInput = new ObjectInputStream(inputBuf);
final XQEventDecoder decoder = new XQEventDecoder(objInput);
try {
return decoder.decode();
} catch (XQueryException e) {
throw new IOException(PrintUtils.prettyPrintStackTrace(e));
}
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
this.type = (Type) in.readObject();
final byte[] b = IOUtils.readBytes(in);
//this.encodedSequence = b;
this.actualSequence = decode(b);
}
public void writeExternal(ObjectOutput out) throws IOException {
doEncode();
out.writeObject(type);
final byte[] b = encodedSequence;
if(b == null) {
throw new IllegalStateException();
}
IOUtils.writeBytes(b, out);
}
}