org.apache.flink.runtime.io.network.buffer.BufferListener Maven / Gradle / Ivy
/*
* 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.flink.runtime.io.network.buffer;
/**
* Interface of the availability of buffers. Listeners can opt for a one-time only
* notification or to be notified repeatedly.
*/
public interface BufferListener {
/**
* Status of the notification result from the buffer listener.
*/
enum NotificationResult {
NONE(false, false),
BUFFER_USED_FINISHED(true, false),
BUFFER_USED_NEED_MORE(true, true);
private final boolean bufferUsed;
private final boolean needsMoreBuffers;
NotificationResult(boolean bufferUsed, boolean needsMoreBuffers) {
this.bufferUsed = bufferUsed;
this.needsMoreBuffers = needsMoreBuffers;
}
/**
* Whether the notified buffer is accepted to use by the listener.
*
* @return true if the notified buffer is accepted.
*/
boolean bufferUsed() {
return bufferUsed;
}
/**
* Whether the listener still needs more buffers to be notified.
*
* @return true if the listener is still waiting for more buffers.
*/
boolean needsMoreBuffers() {
return needsMoreBuffers;
}
}
/**
* Notification callback if a buffer is recycled and becomes available in buffer pool.
*
* @param buffer buffer that becomes available in buffer pool.
* @return NotificationResult if the listener wants to be notified next time.
*/
NotificationResult notifyBufferAvailable(Buffer buffer);
/**
* Notification callback if the buffer provider is destroyed.
*/
void notifyBufferDestroyed();
}