org.springframework.util.ResizableByteArrayOutputStream Maven / Gradle / Ivy
/*
* Copyright 2002-2015 the original author or authors.
*
* 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
*
* https://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.springframework.util;
import java.io.ByteArrayOutputStream;
/**
* An extension of {@link java.io.ByteArrayOutputStream} that:
*
* - has public {@link org.springframework.util.ResizableByteArrayOutputStream#grow(int)}
* and {@link org.springframework.util.ResizableByteArrayOutputStream#resize(int)} methods
* to get more control over the size of the internal buffer
* - has a higher initial capacity (256) by default
*
*
* As of 4.2, this class has been superseded by {@link FastByteArrayOutputStream}
* for Spring's internal use where no assignability to {@link ByteArrayOutputStream}
* is needed (since {@link FastByteArrayOutputStream} is more efficient with buffer
* resize management but doesn't extend the standard {@link ByteArrayOutputStream}).
*
* @author Brian Clozel
* @author Juergen Hoeller
* @since 4.0.3
* @see #resize
* @see FastByteArrayOutputStream
*/
public class ResizableByteArrayOutputStream extends ByteArrayOutputStream {
private static final int DEFAULT_INITIAL_CAPACITY = 256;
/**
* Create a new ResizableByteArrayOutputStream
* with the default initial capacity of 256 bytes.
*/
public ResizableByteArrayOutputStream() {
super(DEFAULT_INITIAL_CAPACITY);
}
/**
* Create a new ResizableByteArrayOutputStream
* with the specified initial capacity.
* @param initialCapacity the initial buffer size in bytes
*/
public ResizableByteArrayOutputStream(int initialCapacity) {
super(initialCapacity);
}
/**
* Resize the internal buffer size to a specified capacity.
* @param targetCapacity the desired size of the buffer
* @throws IllegalArgumentException if the given capacity is smaller than
* the actual size of the content stored in the buffer already
* @see ResizableByteArrayOutputStream#size()
*/
public synchronized void resize(int targetCapacity) {
Assert.isTrue(targetCapacity >= this.count, "New capacity must not be smaller than current size");
byte[] resizedBuffer = new byte[targetCapacity];
System.arraycopy(this.buf, 0, resizedBuffer, 0, this.count);
this.buf = resizedBuffer;
}
/**
* Grow the internal buffer size.
* @param additionalCapacity the number of bytes to add to the current buffer size
* @see ResizableByteArrayOutputStream#size()
*/
public synchronized void grow(int additionalCapacity) {
Assert.isTrue(additionalCapacity >= 0, "Additional capacity must be 0 or higher");
if (this.count + additionalCapacity > this.buf.length) {
int newCapacity = Math.max(this.buf.length * 2, this.count + additionalCapacity);
resize(newCapacity);
}
}
/**
* Return the current size of this stream's internal buffer.
*/
public synchronized int capacity() {
return this.buf.length;
}
}