/*
* @(#)$Id$
*
* 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.expr.opt;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import xbird.engine.remote.RemoteSequence;
import xbird.util.datetime.StopWatch;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.XQEventReceiver;
import xbird.xquery.dm.coder.XQEventDecoder;
import xbird.xquery.dm.coder.XQEventEncoder;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.expr.var.Variable;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.StaticContext;
import xbird.xquery.misc.QNameTable.QualifiedName;
import xbird.xquery.type.Type;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class ShippedVariable extends Variable implements Externalizable {
private static final long serialVersionUID = 7003466767355357342L;
private static final Log LOG = LogFactory.getLog(ShippedVariable.class);
private int _identifier = -1;
private transient boolean _local = true;
public ShippedVariable(Variable var, int identifier) {
super(var.getVarName(), var);
if(_varName == null) {
throw new IllegalArgumentException();
}
if(identifier < 0) {
throw new IllegalArgumentException("Illegal identifier: " + identifier);
}
this._identifier = identifier;
this._result = var.getResult();
this._type = var.getType();
}
public ShippedVariable(QualifiedName varName, Sequence result) {
super(varName);
if(varName == null) {
throw new IllegalArgumentException();
}
if(result == null) {
throw new IllegalArgumentException();
}
this._result = result;
}
public ShippedVariable() {// for Externalizable
super(null);
}
public void setLocal(boolean local) {
this._local = local;
}
public int getIdentifier() {
return _identifier;
}
@Override
public Type getType() {
final Sequence result = _result;
if(result == null) {
return _type;
} else {
return _result.getType();
}
}
@Override
public XQExpression staticAnalysis(StaticContext statEnv) throws XQueryException {
return this;
}
@Override
public Sequence<? extends Item> eval(Sequence<? extends Item> contextSeq, DynamicContext dynEnv)
throws XQueryException {
Sequence result = _result;
if(_local) {
final XQExpression valueExpr = _value;
if(valueExpr == null) {
throw new IllegalStateException();
}
result = valueExpr.eval(contextSeq, dynEnv);
this._result = result;
}
return result;
}
@Override
public void evalAsEvents(XQEventReceiver handler, Sequence<? extends Item> contextSeq, DynamicContext dynEnv)
throws XQueryException {
if(_result != null) {
handler.emit(_result);
} else {
_value.evalAsEvents(handler, contextSeq, dynEnv); //TODO REVIEWME required?
}
}
@Override
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(_type);
out.writeObject(_varName);
out.writeInt(_identifier);
final Sequence result = _result;
if(result == null) {
out.writeBoolean(false);
final XQExpression value = _value;
if(value == null) {
throw new IllegalStateException();
}
out.writeObject(value);
} else {
out.writeBoolean(true);
if(result instanceof RemoteSequence) {
out.writeBoolean(true);
RemoteSequence remote = (RemoteSequence) result;
remote.writeExternal(out);
} else {
out.writeBoolean(false);
final StopWatch sw = new StopWatch("Elapsed time for encoding `$" + getName()
+ '\'');
final XQEventEncoder encoder = new XQEventEncoder(out);
try {
encoder.emit(result);
} catch (XQueryException xqe) {
throw new IllegalStateException("failed encoding `$" + getName() + '\'', xqe);
} catch (Throwable e) {
LOG.fatal(e);
throw new IllegalStateException("failed encoding `$" + getName() + '\'', e);
}
if(LOG.isInfoEnabled()) {
LOG.info(sw);
}
}
}
}
@Override
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
this._local = false;
this._type = (Type) in.readObject();
this._varName = (QualifiedName) in.readObject();
this._identifier = in.readInt();
final boolean hasResult = in.readBoolean();
if(hasResult) {
final boolean isRemoteSeq = in.readBoolean();
if(isRemoteSeq) {
this._result = RemoteSequence.readFrom(in);
} else {
final StopWatch sw = new StopWatch("Elapsed time for decoding `$" + getName()
+ '\'');
final XQEventDecoder decoder = new XQEventDecoder(in);
try {
this._result = decoder.decode();
} catch (XQueryException xqe) {
throw new IllegalStateException("failed decoding `$" + getName() + '\'', xqe);
} catch (Throwable e) {
throw new IllegalStateException("failed decoding `$" + getName() + '\'', e);
}
if(LOG.isInfoEnabled()) {
LOG.info(sw);
}
}
} else {
this._value = (XQExpression) in.readObject();
}
}
public static ShippedVariable readFrom(ObjectInput in) throws IOException,
ClassNotFoundException {
final ShippedVariable var = new ShippedVariable();
var.readExternal(in);
return var;
}
}