/*
* 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
*
* 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.springframework.util;
import java.io.
ByteArrayOutputStream;
/**
* An extension of {@link java.io.ByteArrayOutputStream} that:
* <ul>
* <li>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</li>
* <li>has a higher initial capacity (256) by default</li>
* </ul>
*
* <p>As of 4.2, this class has been superseded by {@link FastByteArrayOutputStream}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 <code>ResizableByteArrayOutputStream</code>
* with the default initial capacity of 256 bytes.
*/
public
ResizableByteArrayOutputStream() {
super(
DEFAULT_INITIAL_CAPACITY);
}
/**
* Create a new <code>ResizableByteArrayOutputStream</code>
* 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;
}
}