ByteBufferFactory.java

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package com.sun.grizzly.util;

import java.nio.ByteBuffer;


/**
 * Factory class used to create {@link ByteBuffer}. 
 *
 * The ByteBuffer can by direct (ByteBufferType.DIRECT) or heap (ByteBufferType.HEAP)
 * a view (ByteBufferType.DIRECT_VIEW) or ByteBufferType.HEAP_VIEW)
 * or backed by an array (ByteBufferType.HEAP_ARRAY).
 *
 * @author Jean-Francois Arcand
 */
public class ByteBufferFactory{

    /**
     * An enumeration of all type of ByteBuffer this object can create.
     */
    public enum ByteBufferType { DIRECT, HEAP, DIRECT_VIEW, HEAP_VIEW, HEAP_ARRAY }
    
    
    /**
     * The default capacity of the default view of a {@link ByteBuffer}
     */ 
    public final static int defaultCapacity = 8192;
    
    
    /**
     * The default capacity of the {@link ByteBuffer} from which views
     * will be created.
     */
    public static int capacity = 4000000; 
    
    
    /**
     * The {@link ByteBuffer} used to create direct byteBuffer view.
     */
    private static ByteBuffer directByteBuffer;
        
    
    /**
     * The {@link ByteBuffer} used to create direct byteBuffer view.
     */
    private static ByteBuffer heapByteBuffer;
    
    
    /**
     * Private constructor.
     */
    private ByteBufferFactory(){
    }
    
    
    /**
     * Return a direct {@link ByteBuffer} view
     * @param size the Size of the {@link ByteBuffer}
     * @param direct - direct or non-direct buffer?
     * @return {@link ByteBuffer}
     */ 
    public final static ByteBuffer allocateView(int size, boolean direct){
      return direct ? ByteBuffer.allocateDirect(size):ByteBuffer.allocate(size);
        /*if (direct && (directByteBuffer == null ||
               (directByteBuffer.capacity() - directByteBuffer.limit() < size))){
            directByteBuffer = ByteBuffer.allocateDirect(capacity);                 
        } else if (heapByteBuffer == null || 
               (heapByteBuffer.capacity() - heapByteBuffer.limit() < size)){
            heapByteBuffer = ByteBuffer.allocate(capacity);            
        }
        ByteBuffer byteBuffer = (direct ? directByteBuffer : heapByteBuffer);

        byteBuffer.limit(byteBuffer.position() + size);
        ByteBuffer view = byteBuffer.slice();
        byteBuffer.position(byteBuffer.limit());  
        
        return view;*/
    }

    
    /**
     * Return a direct {@link ByteBuffer} view using the default size.
     * @param direct - direct or non-direct buffer
     * @return {@link ByteBuffer}
     */ 
    public final static ByteBuffer allocateView(boolean direct){
        return direct ? ByteBuffer.allocateDirect(defaultCapacity) :
            ByteBuffer.allocate(defaultCapacity);
    }
     
    
    /**
     * Return a new ByteBuffer based on the requested <code>ByteBufferType</code>
     * @param type the requested <code>ByteBufferType</code>
     * @param size the {@link ByteBuffer} size.
     * @return a new ByteBuffer based on the requested <code>ByteBufferType</code>
     */
    public final static ByteBuffer allocate(ByteBufferType type,int size){
        return type != ByteBufferType.DIRECT ? ByteBuffer.allocate(size) :
            ByteBuffer.allocateDirect(size);
        /*if (type == ByteBufferType.HEAP){
            return ByteBuffer.allocate(size);
        } else if (type == ByteBufferType.HEAP_VIEW) {
            return allocateView(size,false);
        } else if (type == ByteBufferType.HEAP_ARRAY) {
            return ByteBuffer.wrap(new byte[size]);
        } else if (type == ByteBufferType.DIRECT){
           return ByteBuffer.allocateDirect(size); 
        } else if (type == ByteBufferType.DIRECT_VIEW){
            return allocateView(size,true);
        } else {
            throw new IllegalStateException("Invalid ByteBuffer Type");
        }*/
    }
}