cloudstack/awsapi/src/com/cloud/bridge/io/MultiPartDimeInputStream.java

/*
 * Copyright (C) 2011 Citrix Systems, Inc.  All rights reserved.
 * 
 * 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 com.cloud.bridge.io;

import org.apache.log4j.Logger;


import java.io.InputStream;
import java.io.IOException;

/**  
 * A DIME stream is actually composed of multiple encoded streams.
 * This class is a wrapper around the DimeDelimitedInputStream inorder 
 * to provide a simple iterator like interface for all the streams in a 
 * DIME encoded message.
 */
public class MultiPartDimeInputStream 
{
    protected final static Logger logger = Logger.getLogger(MultiPartDimeInputStream.class);

    protected InputStream is = null;
    protected DimeDelimitedInputStream currentStream = null; 
    
    protected int     count      = 0;
    protected boolean eos        = false; 
    protected String  contentId  = null;
    protected String  type       = null;
    protected String  typeFormat = null;
 
    /**
     * The SOAP stream must be first, call nextInputStream to get
     * access to the first stream and all streams after that.
     * 
     * @param is the true input stream holding the incoming request.
     */
    public MultiPartDimeInputStream( InputStream is ) throws IOException 
    {
        this.is = is;
    }

    
    /**
     * These three methods are DIME specific but provide potentially
     * useful information about the current stream's data.
     * 
     * @return URL or MIME type
     */
    public String getStreamType()
    {
        return type;
    }

    public String getStreamTypeFormat()
    {
    	// Is the type a URI or MIME type or just unknown?
        return typeFormat;
    }

    public String getStreamId()
    {
    	// The soap body might have string identifiers to point to other streams in the message
        return contentId;
    }

    public InputStream getInputStream()
    {
    	return currentStream;
    }
    
    public int available() throws IOException
    {
    	if (eos) return -1;
    	
        if (null == currentStream)
        {
            throw new IOException( "streamClosed -- call nextInputStream()" );
        }
        return currentStream.available();
    }
    
    
    /**
     * Move on to the next stream encoded in the DIME stream.
     * If the current stream has not been all read, then we skip the remaining bytes of
     * that stream.
     * 
     * @return false if no next input stream, true if next input stream ready
     * @throws IOException
     */
    public boolean nextInputStream() throws IOException
    {
    	if ( null == currentStream )
    	{
    		 // on the first call to this function get the first stream
    		 if (0 == count) currentStream = new DimeDelimitedInputStream( is ); 
    	}
    	else
    	{    // make sure the bytes of the previous stream are all skipped before we start the next
    		 currentStream.close();
    	     contentId     = null;
    	     type          = null;
    	     typeFormat    = null;
    	     currentStream = currentStream.getNextStream();
    	}
    	
    	if ( null != currentStream )
    	{
             contentId  = currentStream.getContentId();
             type       = currentStream.getType();
             typeFormat = currentStream.getDimeTypeNameFormat();
             eos        = false;
             count++;
             return true;
    	}
    	else return false;
    }
   
    
    public long skip( long n ) throws IOException
    {
        if (eos || null == currentStream) 
        {
            throw new IOException( "streamClosed -- call nextInputStream()" );
        }
        return currentStream.skip( n );
    }
    
    
    public int read( byte[] b, int off, int len ) throws IOException 
    {
        if (eos || null == currentStream) return -1;
        
        int read = currentStream.read( b, off, len );
        
        if (read < 0) eos = true;
        
        return read;
    }

    
    public int read( byte[] b ) throws IOException 
    {
        return read( b, 0, b.length );
    }

    
    public int read() throws IOException 
    {
        if (eos || null == currentStream) return -1;
       
        int ret = currentStream.read();
        
        if (ret < 0) eos = true;
       
        return ret;
    }
}