org.apache.inlong.common.msg.DataInputBuffer 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.inlong.common.msg;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
/**
* A reusable {@link java.io.DataInput} implementation that reads from an in-memory buffer.
*
* This saves memory over creating a new DataInputStream and
* ByteArrayInputStream each time data is read.
*
* Typical usage is something like the following:
*
* DataInputBuffer buffer = new DataInputBuffer();
* while (... loop condition ...) {
* byte[] data = ... get data ...;
* int dataLength = ... get data length ...;
* buffer.reset(data, dataLength);
* ... read buffer using DataInput methods ...
* }
*/
public class DataInputBuffer extends DataInputStream {
private static class Buffer extends ByteArrayInputStream {
public Buffer() {
super(new byte[]{
//
});
}
public void reset(byte[] input, int start, int length) {
this.buf = input;
this.count = start + length;
this.mark = start;
this.pos = start;
}
public byte[] getData() {
return buf;
}
public int getPosition() {
return pos;
}
public int getLength() {
return count;
}
}
private Buffer buffer;
/**
* Constructs a new empty buffer.
*/
public DataInputBuffer() {
this(new Buffer());
}
private DataInputBuffer(Buffer buffer) {
super(buffer);
this.buffer = buffer;
}
/**
* Resets the data that the buffer reads.
*/
public void reset(byte[] input, int length) {
buffer.reset(input, 0, length);
}
/**
* Resets the data that the buffer reads.
*/
public void reset(byte[] input, int start, int length) {
buffer.reset(input, start, length);
}
public byte[] getData() {
return buffer.getData();
}
/**
* Returns the current position in the input.
*/
public int getPosition() {
return buffer.getPosition();
}
/**
* Returns the length of the input.
*/
public int getLength() {
return buffer.getLength();
}
}