/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.exoplatform.services.jcr.impl.core.query.lucene;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.PayloadAttribute;
import org.apache.lucene.index.Payload;
import org.exoplatform.services.jcr.impl.Constants;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/**
* <code>SingletonTokenStream</code> implements a token stream that wraps a
* single value with a given property type. The property type is stored as a
* payload on the single returned token.
*/
public final class SingletonTokenStream extends TokenStream implements Externalizable
{
/**
* The string value of the token.
*/
private String value;
/**
* The payload of the token.
*/
private Payload payload;
/**
* The term attribute of the current token
*/
private CharTermAttribute termAttribute;
/**
* The payload attribute of the current token
*/
private PayloadAttribute payloadAttribute;
private volatile boolean consumed = false;
/**
* Default constructor for serialization
*/
public SingletonTokenStream()
{
termAttribute = addAttribute(CharTermAttribute.class);
payloadAttribute = addAttribute(PayloadAttribute.class);
}
/**
* Creates a new SingleTokenStream with the given value and payload.
*
* @param value
* the string value that will be returned with the token.
* @param payload
* the payload that will be attached to this token
*/
public SingletonTokenStream(String value, Payload payload)
{
this.value = value;
this.payload = payload;
termAttribute = addAttribute(CharTermAttribute.class);
payloadAttribute = addAttribute(PayloadAttribute.class);
}
/**
* Creates a new SingleTokenStream with the given value and a property
* <code>type</code>.
*
* @param value
* the string value that will be returned with the token.
* @param type
* the JCR property type.
*/
public SingletonTokenStream(String value, int type)
{
this(value, new Payload(new PropertyMetaData(type).toByteArray()));
}
@Override
public boolean incrementToken() throws IOException
{
if (consumed)
{
return false;
}
clearAttributes();
termAttribute.setEmpty();
termAttribute.append(value);
payloadAttribute.setPayload(payload);
consumed = true;
return true;
}
/**
* {@inheritDoc}
*/
@Override
public void reset() throws IOException
{
consumed = false;
if (termAttribute == null)
{
termAttribute = addAttribute(CharTermAttribute.class);
}
if (payloadAttribute == null)
{
payloadAttribute = addAttribute(PayloadAttribute.class);
}
}
/**
* {@inheritDoc}
*/
@Override
public void close() throws IOException
{
consumed = true;
payloadAttribute = null;
termAttribute = null;
}
/**
* {@inheritDoc}
*/
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
{
payload = (Payload)in.readObject();
int length = in.readInt();
byte[] binValue = new byte[length];
in.read(binValue);
value = new String(binValue, Constants.DEFAULT_ENCODING);
}
/**
* {@inheritDoc}
*/
public void writeExternal(ObjectOutput out) throws IOException
{
// skip writing hasNext field
out.writeObject(payload);
byte[] binValue = value.getBytes(Constants.DEFAULT_ENCODING);
out.writeInt(binValue.length);
out.write(binValue);
}
}