alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

ActiveMQ example source code file (DataByteArrayInputStream.java)

This example ActiveMQ source code file (DataByteArrayInputStream.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

databytearrayinputstream, databytearrayinputstream, datainput, inputstream, io, ioexception, ioexception, nullpointerexception, string, string, utfdataformatexception, utfdataformatexception

The ActiveMQ DataByteArrayInputStream.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.activemq.util;

import java.io.DataInput;
import java.io.IOException;
import java.io.InputStream;
import java.io.UTFDataFormatException;

/**
 * Optimized ByteArrayInputStream that can be used more than once
 * 
 * 
 */
public final class DataByteArrayInputStream extends InputStream implements DataInput {
    private byte[] buf;
    private int pos;
    private int offset;

    /**
     * Creates a <code>StoreByteArrayInputStream.
     * 
     * @param buf the input buffer.
     */
    public DataByteArrayInputStream(byte buf[]) {
        this.buf = buf;
        this.pos = 0;
        this.offset = 0;
    }

    /**
     * Creates a <code>StoreByteArrayInputStream.
     * 
     * @param sequence the input buffer.
     */
    public DataByteArrayInputStream(ByteSequence sequence) {
        this.buf = sequence.getData();
        this.offset = sequence.getOffset();
        this.pos =  this.offset;
    }

    /**
     * Creates <code>WireByteArrayInputStream with a minmalist byte
     * array
     */
    public DataByteArrayInputStream() {
        this(new byte[0]);
    }

    /**
     * @return the size
     */
    public int size() {
        return pos - offset;
    }

    /**
     * @return the underlying data array
     */
    public byte[] getRawData() {
        return buf;
    }

    /**
     * reset the <code>StoreByteArrayInputStream to use an new byte
     * array
     * 
     * @param newBuff
     */
    public void restart(byte[] newBuff) {
        buf = newBuff;
        pos = 0;
    }

    /**
     * reset the <code>StoreByteArrayInputStream to use an new
     * ByteSequence
     * 
     * @param sequence
     */
    public void restart(ByteSequence sequence) {
        this.buf = sequence.getData();
        this.pos = sequence.getOffset();
    }

    /**
     * re-start the input stream - reusing the current buffer
     * 
     * @param size
     */
    public void restart(int size) {
        if (buf == null || buf.length < size) {
            buf = new byte[size];
        }
        restart(buf);
    }

    /**
     * Reads the next byte of data from this input stream. The value byte is
     * returned as an <code>int in the range 0 to
     * <code>255. If no byte is available because the end of the
     * stream has been reached, the value <code>-1 is returned.
     * <p>
     * This <code>read method cannot block.
     * 
     * @return the next byte of data, or <code>-1 if the end of the
     *         stream has been reached.
     */
    public int read() {
        return (pos < buf.length) ? (buf[pos++] & 0xff) : -1;
    }

    /**
     * Reads up to <code>len bytes of data into an array of bytes from
     * this input stream.
     * 
     * @param b the buffer into which the data is read.
     * @param off the start offset of the data.
     * @param len the maximum number of bytes read.
     * @return the total number of bytes read into the buffer, or
     *         <code>-1 if there is no more data because the end of the
     *         stream has been reached.
     */
    public int read(byte b[], int off, int len) {
        if (b == null) {
            throw new NullPointerException();
        }
        if (pos >= buf.length) {
            return -1;
        }
        if (pos + len > buf.length) {
            len = buf.length - pos;
        }
        if (len <= 0) {
            return 0;
        }
        System.arraycopy(buf, pos, b, off, len);
        pos += len;
        return len;
    }

    /**
     * @return the number of bytes that can be read from the input stream
     *         without blocking.
     */
    public int available() {
        return buf.length - pos;
    }

    public void readFully(byte[] b) {
        read(b, 0, b.length);
    }

    public void readFully(byte[] b, int off, int len) {
        read(b, off, len);
    }

    public int skipBytes(int n) {
        if (pos + n > buf.length) {
            n = buf.length - pos;
        }
        if (n < 0) {
            return 0;
        }
        pos += n;
        return n;
    }

    public boolean readBoolean() {
        return read() != 0;
    }

    public byte readByte() {
        return (byte)read();
    }

    public int readUnsignedByte() {
        return read();
    }

    public short readShort() {
        int ch1 = read();
        int ch2 = read();
        return (short)((ch1 << 8) + (ch2 << 0));
    }

    public int readUnsignedShort() {
        int ch1 = read();
        int ch2 = read();
        return (ch1 << 8) + (ch2 << 0);
    }

    public char readChar() {
        int ch1 = read();
        int ch2 = read();
        return (char)((ch1 << 8) + (ch2 << 0));
    }

    public int readInt() {
        int ch1 = read();
        int ch2 = read();
        int ch3 = read();
        int ch4 = read();
        return (ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0);
    }

    public long readLong() {
        long rc = ((long)buf[pos++] << 56) + ((long)(buf[pos++] & 255) << 48) + ((long)(buf[pos++] & 255) << 40) + ((long)(buf[pos++] & 255) << 32);
        return rc + ((long)(buf[pos++] & 255) << 24) + ((buf[pos++] & 255) << 16) + ((buf[pos++] & 255) << 8) + ((buf[pos++] & 255) << 0);
    }

    public float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }

    public double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }

    public String readLine() {
        int start = pos;
        while (pos < buf.length) {
            int c = read();
            if (c == '\n') {
                break;
            }
            if (c == '\r') {
                c = read();
                if (c != '\n' && c != -1) {
                    pos--;
                }
                break;
            }
        }
        return new String(buf, start, pos);
    }

    public String readUTF() throws IOException {
        int length = readUnsignedShort();
        char[] characters = new char[length];
        int c;
        int c2;
        int c3;
        int count = 0;
        int total = pos + length;
        while (pos < total) {
            c = (int)buf[pos] & 0xff;
            if (c > 127) {
                break;
            }
            pos++;
            characters[count++] = (char)c;
        }
        while (pos < total) {
            c = (int)buf[pos] & 0xff;
            switch (c >> 4) {
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
            case 6:
            case 7:
                pos++;
                characters[count++] = (char)c;
                break;
            case 12:
            case 13:
                pos += 2;
                if (pos > total) {
                    throw new UTFDataFormatException("bad string");
                }
                c2 = (int)buf[pos - 1];
                if ((c2 & 0xC0) != 0x80) {
                    throw new UTFDataFormatException("bad string");
                }
                characters[count++] = (char)(((c & 0x1F) << 6) | (c2 & 0x3F));
                break;
            case 14:
                pos += 3;
                if (pos > total) {
                    throw new UTFDataFormatException("bad string");
                }
                c2 = (int)buf[pos - 2];
                c3 = (int)buf[pos - 1];
                if (((c2 & 0xC0) != 0x80) || ((c3 & 0xC0) != 0x80)) {
                    throw new UTFDataFormatException("bad string");
                }
                characters[count++] = (char)(((c & 0x0F) << 12) | ((c2 & 0x3F) << 6) | ((c3 & 0x3F) << 0));
                break;
            default:
                throw new UTFDataFormatException("bad string");
            }
        }
        return new String(characters, 0, count);
    }
}

Other ActiveMQ examples (source code examples)

Here is a short list of links related to this ActiveMQ DataByteArrayInputStream.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.