/*
* Copyright 2013 Netflix, Inc.
*
* 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.
*/
package com.netflix.suro.message;
import com.google.common.io.ByteArrayDataInput;
import com.google.common.io.ByteStreams;
import com.netflix.servo.monitor.DynamicCounter;
import com.netflix.servo.monitor.MonitorConfig;
import com.netflix.suro.TagKey;
import com.netflix.suro.thrift.TMessageSet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Iterator;
/**
* This class implements an {@link Iterable} reader for {@link TMessageSet} so we can iterate
* over each message in a {@link TMessageSet}.
*
* @author jbae
*/
public class MessageSetReader implements Iterable<Message> {
private static final Logger log = LoggerFactory.getLogger(MessageSetReader.class);
private final TMessageSet messageSet;
public MessageSetReader(TMessageSet messageSet) {
this.messageSet = messageSet;
}
public boolean checkCRC() {
long crcReceived = messageSet.getCrc();
long crc = MessageSetBuilder.getCRC(messageSet.getMessages());
return crcReceived == crc;
}
@Override
public Iterator<Message> iterator() {
try {
final ByteArrayDataInput input = ByteStreams.newDataInput(
Compression.create(messageSet.getCompression()).decompress(messageSet.getMessages()));
return new Iterator<Message>() {
private int messageCount = messageSet.getNumMessages();
@Override
public boolean hasNext() {
return messageCount > 0;
}
@Override
public Message next() {
Message m = new Message();
try {
m.readFields(input);
--messageCount;
return m;
} catch (Exception e) {
log.error("Exception while iterating MessageSet:" + e.getMessage(), e);
DynamicCounter.increment(
MonitorConfig.builder(TagKey.DROPPED_COUNT)
.withTag("reason", "MessageSetReaderError").build(),
messageCount);
messageCount = 0; // discard further messages
return null;
}
}
@Override
public void remove() {
throw new UnsupportedOperationException("remove is not supported");
}
};
} catch (Exception e) {
log.error("Exception while reading: " + e.getMessage(), e);
return new Iterator<Message>() {
@Override
public boolean hasNext() {
return false;
}
@Override
public Message next() {
return null;
}
@Override
public void remove() {
throw new UnsupportedOperationException("remove is not supported");
}
};
}
}
}