messageelementimpl.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: MessageElementImpl.java,v 1.2 2002/03/04 21:42:57 echtcherbina Exp $
 */
package net.jxta.impl.endpoint;

import net.jxta.document.MimeMediaType;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.MessageElement;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Vector;

/**
 *
 * @author  chgenly
 * @version
 */
public class MessageElementImpl extends MessageElement {
    private String name;
    private MimeMediaType type;
    private byte[] bytes;
    private int offset;
    private int len;
    
    /**
     * Create a new Element, but dont add it to the message. The contents
     * of the byte array are not copied.
     *
     * @param name Name of the Element. May be the empty string ("") if
     *   the Element is not named.
     * @param type Type of the Element. null is equivalent to specifying
     *   the type "Application/Octet-stream"
     * @param b A byte array containing the contents of this element.
     * @param offset all bytes before this location in <code>b</code>
     *   will be ignored.
     * @param len the number of bytes of the array starting from offset to
     *  use as the content of this element.
     *
     * @throws NullPointerException if name or b are null.
     * @throws IndexOutOfBoundsException if offset is negative or greater
     *  than or equal to the length of <code>b</code>
     *
     * @since JXTA 1.0
     */
    public MessageElementImpl(String name, MimeMediaType type, byte[] b,
    int offset, int len) {
        this.name = name;
        
        if( null != type )
            this.type = type;
        else
            this.type = new MimeMediaType( "application/octet-stream" );
        
        bytes = b;
        this.offset = offset;
        this.len = len;
    }
    
    
    /**
     *  Create a new Element, but don't add it to the message.
     *
     *  @param name Name of the Element. May be the empty string ("") if
     *   the Element is not named.
     *  @param type Type of the Element. null is equivalent to specifying
     *   the type "Application/Octet-stream"
     *  @param in the stream containing the body of the Element. If the
     *   stream does not support the "mark" operation then a copy of the
     *   stream contents is made immediately. The stream will <b>NOT</b> be
     *   closed by the Element.
     *  @param len The size of the Element will be limited to len bytes
     *   from the stream. If you are using the stream interface and know
     *   the size of the stream, specifying it here improves performance
     *   and space effciency a lot.  If the len is -1, then the input
     *   stream will be read until end of file, and then the stream will
     *   be closed.
     *
     *  @throws NullPointerException if name or InputStream are null.
     *
     * @since JXTA 1.0
     */
    public MessageElementImpl(String name, MimeMediaType type,
    InputStream in, int len) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream(len<0 ? 1024 : len);
        byte[] buff = new byte[1024];
        this.name = name;
        this.type = type;
        int tcnt = 0;
        while(len < 0 || tcnt < len) {
            int needed = len - tcnt;
            int thistime = len < 0 || needed > 1024 ? 1024 : needed;
            int cnt = in.read(buff, 0, thistime);
            if (cnt <= 0) break;
            baos.write(buff, 0, cnt);
            tcnt += cnt;
        }
        this.offset = 0;
        this.len = tcnt;
        bytes = baos.toByteArray();
        
        if (len < 0)
            in.close();
    }
    
    /**
     *  Create a new MessageElement
     *
     *  @param name Name of the Element. May be the empty string ("") if
     *   the Element is not named.
     *  @param type Type of the Element. null is equivalent to specifying
     *   the type "Application/Octet-stream"
     *  @param in the stream containing the body of the Element. The stream
     * will be closed by the Element.
     *
     *  @throws NullPointerException if name or InputStream are null.
     *
     */
    public MessageElementImpl(String name, MimeMediaType type,
    InputStream in) throws IOException {
        this(name, type, in, -1);
        in.close();
    }
    
    /**
     * Returns the offset into the array returned by getBytes()
     * of where data use by this element starts.
     */
    public int getOffset() {
        return offset;
    }
    
    /**
     *   Returns the number of bytes used in the array
     *   returned by getBytes().  This may or may not be the
     *   entire length of the array returned by getBytes().
     *   <P>
     *   post:<br>
     *   0 <= getLength() <= getBytes().length
     *
     *
     *   @return int the number of bytes of the element data.
     *
     *  @since JXTA 1.0
     **/
    public int getLength() {
        return len;
    }
    
    
    /**
     *   Returns the byte array which contains the element data.
     *   The portion of the array
     *   which is used as the element data starts at getOffset()
     *   and continues up to but not including the byte at
     *   getOffset()+getLength().
     *   <P>
     *   The byte array returned is not a copy of the element
     *   content.
     *
     *   @return byte[] Contents of message element.
     */
    public byte[] getBytesOffset() {
        return bytes;
    }
    
    /**
     *   Returns a stream containing the element data.
     *
     *   @return InputStream of the stream containing element data.
     *
     *  @since JXTA 1.0
     **/
    public InputStream getStream() {
        return new ByteArrayInputStream(bytes, offset, len);
    }
    
    /**
     *  Returns the name of the MessageElement.
     *
     *  @return String containing the name of the MessageElement.
     *
     *  @since JXTA 1.0
     **/
    public String getName() {
        return name;
    }
    
    /**
     *  Returns the type of the MessageElement.
     *
     *  @return MimeMediaType containing a copy of the type of the element.
     *   Will return "Application/Octet-Stream" if no type was originally
     *   specified.
     *
     *  @since JXTA 1.0
     **/
    public MimeMediaType getType() {
        return type;
    }
    
    /**
     *  make a clone of this element. Since element are immutable, this
     *  returns the same object.
     *
     *  @return Element a clone of this element.
     *
     *  @since JXTA 1.0
     **/
    public Object clone( ) {
        return this;
    }
    
    /**
     *  Compare this MessageElement against another
     *
     *  @param target The  to compare against.
     *  @return boolean true if the elements are identical.
     *
     *  @since JXTA 1.0
     **/
    public boolean equals( Object target ) {
        if (!(target instanceof MessageElement))
            return false;
        MessageElement other = (MessageElement)target;
        
        if (name == null ? other.getName() != null
        : !name.equals(other.getName()))
            return false;
        
        if (type == null ? other.getType() != null
        : !type.equals(other.getType()))
            return false;
        
        if (len != other.getLength())
            return false;
        
        byte[] otherBytes = other.getBytesOffset();
        int otherI = other.getOffset();
        for(int i=0; i<len; ++i)
            if (bytes[offset+i] != otherBytes[otherI++])
                return false;
        
        return true;
    }
}