org.apache.flink.runtime.state.memory.ByteStreamStateHandle 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.state.memory;
import org.apache.flink.core.fs.FSDataInputStream;
import org.apache.flink.runtime.state.StreamStateHandle;
import org.apache.flink.util.Preconditions;
import java.io.IOException;
/**
* A state handle that contains stream state in a byte array.
*/
public class ByteStreamStateHandle implements StreamStateHandle {
private static final long serialVersionUID = -5280226231202517594L;
/**
* The state data.
*/
private final byte[] data;
/**
* A unique name of by which this state handle is identified and compared. Like a filename, all
* {@link ByteStreamStateHandle} with the exact same name must also have the exact same content in data.
*/
private final String handleName;
/**
* Creates a new ByteStreamStateHandle containing the given data.
*/
public ByteStreamStateHandle(String handleName, byte[] data) {
this.handleName = Preconditions.checkNotNull(handleName);
this.data = Preconditions.checkNotNull(data);
}
@Override
public FSDataInputStream openInputStream() throws IOException {
return new ByteStateHandleInputStream(data);
}
public byte[] getData() {
return data;
}
public String getHandleName() {
return handleName;
}
@Override
public void discardState() {
}
@Override
public long getStateSize() {
return data.length;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof ByteStreamStateHandle)) {
return false;
}
ByteStreamStateHandle that = (ByteStreamStateHandle) o;
return handleName.equals(that.handleName);
}
@Override
public int hashCode() {
return 31 * handleName.hashCode();
}
@Override
public String toString() {
return "ByteStreamStateHandle{" +
"handleName='" + handleName + '\'' +
", dataBytes=" + data.length +
'}';
}
/**
* An input stream view on a byte array.
*/
private static final class ByteStateHandleInputStream extends FSDataInputStream {
private final byte[] data;
private int index;
public ByteStateHandleInputStream(byte[] data) {
this.data = data;
}
@Override
public void seek(long desired) throws IOException {
if (desired >= 0 && desired <= data.length) {
index = (int) desired;
} else {
throw new IOException("position out of bounds");
}
}
@Override
public long getPos() throws IOException {
return index;
}
@Override
public int read() throws IOException {
return index < data.length ? data[index++] & 0xFF : -1;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
// note that any bounds checking on "byte[] b" happend anyways by the
// System.arraycopy() call below, so we don't add extra checks here
final int bytesLeft = data.length - index;
if (bytesLeft > 0) {
final int bytesToCopy = Math.min(len, bytesLeft);
System.arraycopy(data, index, b, off, bytesToCopy);
index += bytesToCopy;
return bytesToCopy;
}
else {
return -1;
}
}
}
}