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ActiveMQ example source code file (DataByteArrayOutputStream.java)

This example ActiveMQ source code file (DataByteArrayOutputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

bytesequence, bytesequence, databytearrayoutputstream, databytearrayoutputstream, dataoutput, default_size, illegalargumentexception, illegalargumentexception, invalid, io, ioexception, ioexception, outputstream, utfdataformatexception

The ActiveMQ DataByteArrayOutputStream.java source code

/**
 * 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.kahadb.util;

import java.io.DataOutput;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UTFDataFormatException;

/**
 * Optimized ByteArrayOutputStream
 * 
 * 
 */
public class DataByteArrayOutputStream extends OutputStream implements DataOutput {
    private static final int DEFAULT_SIZE = 2048;
    protected byte buf[];
    protected int pos;

    /**
     * Creates a new byte array output stream, with a buffer capacity of the
     * specified size, in bytes.
     * 
     * @param size the initial size.
     * @exception IllegalArgumentException if size is negative.
     */
    public DataByteArrayOutputStream(int size) {
        if (size < 0) {
            throw new IllegalArgumentException("Invalid size: " + size);
        }
        buf = new byte[size];
    }

    /**
     * Creates a new byte array output stream.
     */
    public DataByteArrayOutputStream() {
        this(DEFAULT_SIZE);
    }

    /**
     * start using a fresh byte array
     * 
     * @param size
     */
    public void restart(int size) {
        buf = new byte[size];
        pos = 0;
    }

    /**
     * start using a fresh byte array
     */
    public void restart() {
        restart(DEFAULT_SIZE);
    }

    /**
     * Get a ByteSequence from the stream
     * 
     * @return the byte sequence
     */
    public ByteSequence toByteSequence() {
        return new ByteSequence(buf, 0, pos);
    }

    /**
     * Writes the specified byte to this byte array output stream.
     * 
     * @param b the byte to be written.
     * @throws IOException 
     */
    public void write(int b) throws IOException {
        int newcount = pos + 1;
        ensureEnoughBuffer(newcount);
        buf[pos] = (byte)b;
        pos = newcount;
        onWrite();
    }

    /**
     * Writes <code>len bytes from the specified byte array starting at
     * offset <code>off to this byte array output stream.
     * 
     * @param b the data.
     * @param off the start offset in the data.
     * @param len the number of bytes to write.
     * @throws IOException 
     */
    public void write(byte b[], int off, int len) throws IOException {
        if (len == 0) {
            return;
        }
        int newcount = pos + len;
        ensureEnoughBuffer(newcount);
        System.arraycopy(b, off, buf, pos, len);
        pos = newcount;
        onWrite();
    }

    /**
     * @return the underlying byte[] buffer
     */
    public byte[] getData() {
        return buf;
    }

    /**
     * reset the output stream
     */
    public void reset() {
        pos = 0;
    }

    /**
     * Set the current position for writing
     * 
     * @param offset
     * @throws IOException 
     */
    public void position(int offset) throws IOException {
        ensureEnoughBuffer(offset);
        pos = offset;
        onWrite();
    }

    public int size() {
        return pos;
    }

    public void writeBoolean(boolean v) throws IOException {
        ensureEnoughBuffer(pos + 1);
        buf[pos++] = (byte)(v ? 1 : 0);
        onWrite();
    }

    public void writeByte(int v) throws IOException {
        ensureEnoughBuffer(pos + 1);
        buf[pos++] = (byte)(v >>> 0);
        onWrite();
    }

    public void writeShort(int v) throws IOException {
        ensureEnoughBuffer(pos + 2);
        buf[pos++] = (byte)(v >>> 8);
        buf[pos++] = (byte)(v >>> 0);
        onWrite();
    }

    public void writeChar(int v) throws IOException {
        ensureEnoughBuffer(pos + 2);
        buf[pos++] = (byte)(v >>> 8);
        buf[pos++] = (byte)(v >>> 0);
        onWrite();
    }

    public void writeInt(int v) throws IOException {
        ensureEnoughBuffer(pos + 4);
        buf[pos++] = (byte)(v >>> 24);
        buf[pos++] = (byte)(v >>> 16);
        buf[pos++] = (byte)(v >>> 8);
        buf[pos++] = (byte)(v >>> 0);
        onWrite();
    }

    public void writeLong(long v) throws IOException {
        ensureEnoughBuffer(pos + 8);
        buf[pos++] = (byte)(v >>> 56);
        buf[pos++] = (byte)(v >>> 48);
        buf[pos++] = (byte)(v >>> 40);
        buf[pos++] = (byte)(v >>> 32);
        buf[pos++] = (byte)(v >>> 24);
        buf[pos++] = (byte)(v >>> 16);
        buf[pos++] = (byte)(v >>> 8);
        buf[pos++] = (byte)(v >>> 0);
        onWrite();
    }

    public void writeFloat(float v) throws IOException {
        writeInt(Float.floatToIntBits(v));
    }

    public void writeDouble(double v) throws IOException {
        writeLong(Double.doubleToLongBits(v));
    }

    public void writeBytes(String s) throws IOException {
        int length = s.length();
        for (int i = 0; i < length; i++) {
            write((byte)s.charAt(i));
        }
    }

    public void writeChars(String s) throws IOException {
        int length = s.length();
        for (int i = 0; i < length; i++) {
            int c = s.charAt(i);
            write((c >>> 8) & 0xFF);
            write((c >>> 0) & 0xFF);
        }
    }

    public void writeUTF(String str) throws IOException {
        int strlen = str.length();
        int encodedsize = 0;
        int c;
        for (int i = 0; i < strlen; i++) {
            c = str.charAt(i);
            if ((c >= 0x0001) && (c <= 0x007F)) {
                encodedsize++;
            } else if (c > 0x07FF) {
                encodedsize += 3;
            } else {
                encodedsize += 2;
            }
        }
        if (encodedsize > 65535) {
            throw new UTFDataFormatException("encoded string too long: " + encodedsize + " bytes");
        }
        ensureEnoughBuffer(pos + encodedsize + 2);
        writeShort(encodedsize);
        int i = 0;
        for (i = 0; i < strlen; i++) {
            c = str.charAt(i);
            if (!((c >= 0x0001) && (c <= 0x007F))) {
                break;
            }
            buf[pos++] = (byte)c;
        }
        for (; i < strlen; i++) {
            c = str.charAt(i);
            if ((c >= 0x0001) && (c <= 0x007F)) {
                buf[pos++] = (byte)c;
            } else if (c > 0x07FF) {
                buf[pos++] = (byte)(0xE0 | ((c >> 12) & 0x0F));
                buf[pos++] = (byte)(0x80 | ((c >> 6) & 0x3F));
                buf[pos++] = (byte)(0x80 | ((c >> 0) & 0x3F));
            } else {
                buf[pos++] = (byte)(0xC0 | ((c >> 6) & 0x1F));
                buf[pos++] = (byte)(0x80 | ((c >> 0) & 0x3F));
            }
        }
        onWrite();
    }

    private void ensureEnoughBuffer(int newcount) {
        if (newcount > buf.length) {
            byte newbuf[] = new byte[Math.max(buf.length << 1, newcount)];
            System.arraycopy(buf, 0, newbuf, 0, pos);
            buf = newbuf;
        }
    }
    
    /**
     * This method is called after each write to the buffer.  This should allow subclasses 
     * to take some action based on the writes, for example flushing data to an external system based on size. 
     */
    protected void onWrite() throws IOException {
    }

    public void skip(int size) throws IOException {
        ensureEnoughBuffer(pos + size);
        pos+=size;
        onWrite();
    }

    public ByteSequence getByteSequence() {
        return new ByteSequence(buf, 0, pos);
    }
}

Other ActiveMQ examples (source code examples)

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