/*
* 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.nifi.io.nio.consumer;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.nifi.io.nio.BufferPool;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;
/**
*
*/
public abstract class AbstractStreamConsumer implements StreamConsumer {
private final String uniqueId;
private BufferPool bufferPool = null;
private final BlockingQueue<ByteBuffer> filledBuffers = new LinkedBlockingQueue<>();
private final AtomicBoolean streamEnded = new AtomicBoolean(false);
private final AtomicBoolean consumerEnded = new AtomicBoolean(false);
public AbstractStreamConsumer(final String id) {
uniqueId = id;
}
@Override
public final void setReturnBufferQueue(final BufferPool returnQueue) {
bufferPool = returnQueue;
}
@Override
public final void addFilledBuffer(final ByteBuffer buffer) {
if (isConsumerFinished()) {
buffer.clear();
bufferPool.returnBuffer(buffer, buffer.remaining());
} else {
filledBuffers.add(buffer);
}
}
@Override
public final void process() throws IOException {
if (isConsumerFinished()) {
return;
}
if (streamEnded.get() && filledBuffers.isEmpty()) {
consumerEnded.set(true);
onConsumerDone();
return;
}
final ByteBuffer buffer = filledBuffers.poll();
if (buffer != null) {
final int bytesToProcess = buffer.remaining();
try {
processBuffer(buffer);
} finally {
buffer.clear();
bufferPool.returnBuffer(buffer, bytesToProcess);
}
}
}
protected abstract void processBuffer(ByteBuffer buffer) throws IOException;
@Override
public final void signalEndOfStream() {
streamEnded.set(true);
}
/**
* Convenience method that is called when the consumer is done processing
* based on being told the signal is end of stream and has processed all
* given buffers.
*/
protected void onConsumerDone() {
}
@Override
public final boolean isConsumerFinished() {
return consumerEnded.get();
}
@Override
public final String getId() {
return uniqueId;
}
@Override
public final boolean equals(final Object obj) {
if (obj == null) {
return false;
}
if (obj == this) {
return true;
}
if (obj.getClass() != getClass()) {
return false;
}
AbstractStreamConsumer rhs = (AbstractStreamConsumer) obj;
return new EqualsBuilder().appendSuper(super.equals(obj)).append(uniqueId, rhs.uniqueId).isEquals();
}
@Override
public final int hashCode() {
return new HashCodeBuilder(19, 23).append(uniqueId).toHashCode();
}
@Override
public final String toString() {
return new ToStringBuilder(this, ToStringStyle.NO_FIELD_NAMES_STYLE).append(uniqueId).toString();
}
}