MemoryStringWriter.java Source code

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Here is the source code for MemoryStringWriter.java

Source

/**
 * 
 * JFreeReport : a free Java reporting library
 * 
 *
 * Project Info:  http://reporting.pentaho.org/
 *
 * (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ------------
 * MemoryStringWriter.java
 * ------------
 * (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
 */

import java.io.IOException;
import java.io.Writer;

/**
 * A string writer that is able to write large amounts of data. The original
 * StringWriter contained in Java doubles its buffersize everytime the buffer
 * overflows. This is nice with small amounts of data, but awfull for huge
 * buffers.
 * 
 * @author Thomas Morgner
 */
public class MemoryStringWriter extends Writer {
    private int bufferIncrement;

    private int cursor;

    private char[] buffer;

    private int maximumBufferIncrement;

    /**
     * Create a new character-stream writer whose critical sections will
     * synchronize on the writer itself.
     */
    public MemoryStringWriter() {
        this(4096);
    }

    /**
     * Create a new character-stream writer whose critical sections will
     * synchronize on the writer itself.
     */
    public MemoryStringWriter(final int bufferSize) {
        this(bufferSize, bufferSize * 4);
    }

    public MemoryStringWriter(final int bufferSize, final int maximumBufferIncrement) {
        this.maximumBufferIncrement = maximumBufferIncrement;
        this.bufferIncrement = bufferSize;
        this.buffer = new char[bufferSize];
    }

    /**
     * Write a portion of an array of characters.
     * 
     * @param cbuf
     *          Array of characters
     * @param off
     *          Offset from which to start writing characters
     * @param len
     *          Number of characters to write
     * @throws java.io.IOException
     *           If an I/O error occurs
     */
    public synchronized void write(final char[] cbuf, final int off, final int len) throws IOException {
        if (len < 0) {
            throw new IllegalArgumentException();
        }
        if (off < 0) {
            throw new IndexOutOfBoundsException();
        }
        if (cbuf == null) {
            throw new NullPointerException();
        }
        if ((len + off) > cbuf.length) {
            throw new IndexOutOfBoundsException();
        }

        ensureSize(cursor + len);

        System.arraycopy(cbuf, off, this.buffer, cursor, len);
        cursor += len;
    }

    private void ensureSize(final int size) {
        if (this.buffer.length >= size) {
            return;
        }

        final int computedSize = (int) Math.min((this.buffer.length + 1) * 1.5,
                this.buffer.length + maximumBufferIncrement);
        final int newSize = Math.max(size, computedSize);
        final char[] newBuffer = new char[newSize];
        System.arraycopy(this.buffer, 0, newBuffer, 0, cursor);
        this.buffer = newBuffer;
    }

    /**
     * Flush the stream. If the stream has saved any characters from the various
     * write() methods in a buffer, write them immediately to their intended
     * destination. Then, if that destination is another character or byte stream,
     * flush it. Thus one flush() invocation will flush all the buffers in a chain
     * of Writers and OutputStreams. <p/> If the intended destination of this
     * stream is an abstraction provided by the underlying operating system, for
     * example a file, then flushing the stream guarantees only that bytes
     * previously written to the stream are passed to the operating system for
     * writing; it does not guarantee that they are actually written to a physical
     * device such as a disk drive.
     * 
     * @throws java.io.IOException
     *           If an I/O error occurs
     */
    public void flush() throws IOException {

    }

    /**
     * Close the stream, flushing it first. Once a stream has been closed, further
     * write() or flush() invocations will cause an IOException to be thrown.
     * Closing a previously-closed stream, however, has no effect.
     * 
     * @throws java.io.IOException
     *           If an I/O error occurs
     */
    public void close() throws IOException {
    }

    public int getCursor() {
        return cursor;
    }

    public String toString() {
        return new String(buffer, 0, cursor);
    }
}