/**
* 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.apache.activemq.store.amq.reader;
import java.util.Iterator;
import javax.jms.Message;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.filter.BooleanExpression;
import org.apache.activemq.filter.MessageEvaluationContext;
/**
* An Iterator for the AMQReader
*
*/
class AMQIterator implements Iterator<Message>{
private AMQReader reader;
private BooleanExpression expression;
private MessageLocation currentLocation;
private MessageLocation nextLocation;
private boolean valid=true;
AMQIterator(AMQReader reader, BooleanExpression expression){
this.reader=reader;
this.expression=expression;
}
public boolean hasNext() {
try {
this.nextLocation = reader.getNextMessage(currentLocation);
Message next = nextLocation != null ? nextLocation.getMessage()
: null;
if (expression == null) {
return next != null;
} else {
while (next != null) {
MessageEvaluationContext context = new MessageEvaluationContext();
context.setMessageReference((MessageReference) next);
if (expression.matches(context)) {
return true;
}
this.nextLocation = reader.getNextMessage(currentLocation);
next = nextLocation != null ? nextLocation.getMessage()
: null;
}
valid=false;
return false;
}
} catch (Exception e) {
throw new RuntimeException(
"Failed to get next message from reader ", e);
}
}
public Message next() {
if (valid && (nextLocation != null || hasNext())) {
this.currentLocation=nextLocation;
return nextLocation.getMessage();
}
return null;
}
public void remove() {
throw new IllegalStateException("Not supported");
}
}
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