/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.core.api.util.cache;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.OutputStream;

 import java.io.Serializable;

 /**

  * Container class to simplify getting both a deepCopied object and its size returned from a single call to deepCopy.

  */

 public class CopiedObject<T extends Serializable> {

     //private Serializable content;

     private byte[] content;

     private int size;

     private int oldSize;

     public CopiedObject() {

         oldSize = -1;

     }

     public CopiedObject( T cacheableObject ) {

         oldSize = -1;

         setContent( cacheableObject );

     }

     /**

      * @return current value of bytes.

      */

     public int getSize() {

         return size;

     }

     /**

      * @return current value of cacheableObject.

      */

     public T getContent() {

         T copy = null;

         if (content != null) {

             ObjectInputStream ois = null;

             try {

                 FastByteArrayInputStream deserializer = new FastByteArrayInputStream(content,size);

                 ois = new ObjectInputStream(deserializer);

                 copy = (T) ois.readObject();

             }

             catch (IOException e) {

                 throw new CacheException("unable to complete getContent()", e);

             }

             catch (ClassNotFoundException e) {

                 throw new CacheException("unable to complete getContent()", e);

             }

             finally {

                 try {

                     if (ois != null) {

                         ois.close();

                     }

                 }

                 catch (IOException e) {

                     // ignoring this IOException, since the streams are going to be abandoned now anyway

                 }

             }

         }

         return copy;

     }

     /**

      * Sets the cacheableObject attribute value.

      * 

      * @param cacheableObject The cacheableObject to set.

      */

     public void setContent(T cacheableObject) {

         int copySize = 0;

         if (cacheableObject != null) {

             ObjectOutputStream oos = null;

             try {

                 FastByteArrayOutputStream serializer = new FastByteArrayOutputStream();

                 oos = new ObjectOutputStream(serializer);

                 oos.writeObject(cacheableObject);

                 if ( content != null ) {

                     oldSize = size;

                 }

                 size = serializer.getSize();

                 content = serializer.getByteArray();

             } catch (IOException e) {

                 throw new CacheException("unable to complete deepCopy from src '" + cacheableObject.toString() + "'", e);

             }

             finally {

                 try {

                     if (oos != null) {

                         oos.close();

                     }

                 } catch (IOException e) {

                     // ignoring this IOException, since the streams are going to be abandoned now anyway

                 }

             }

         }

     }

     /**

      * @return current value of oldSize.

      */

     public int getOldSize() {

         return oldSize;

     }

     /**

      * ByteArrayOutputStream implementation that doesn't synchronize methods

      * and doesn't copy the data on toByteArray().

      */

     private static class FastByteArrayOutputStream extends OutputStream {

         /**

          * Buffer and size

          */

         protected byte[] buf = null;

         protected int size = 0;

         /**

          * Constructs a stream with buffer capacity size 5K

          */

         public FastByteArrayOutputStream() {

             this(5 * 1024);

         }

         /**

          * Constructs a stream with the given initial size

          */

         public FastByteArrayOutputStream(int initSize) {

             this.size = 0;

             this.buf = new byte[initSize];

         }

         /**

          * Ensures that we have a large enough buffer for the given size.

          */

         private void verifyBufferSize(int sz) {

             if (sz > buf.length) {

                 byte[] old = buf;

                 buf = new byte[Math.max(sz, 2 * buf.length )];

                 System.arraycopy(old, 0, buf, 0, old.length);

                 old = null;

             }

         }

         public int getSize() {

             return size;

         }

         /**

          * Returns the byte array containing the written data. Note that this

          * array will almost always be larger than the amount of data actually

          * written.

          */

         public byte[] getByteArray() {

             return buf;

         }

         public final void write(byte b[]) {

             verifyBufferSize(size + b.length);

             System.arraycopy(b, 0, buf, size, b.length);

             size += b.length;

         }

         public final void write(byte b[], int off, int len) {

             verifyBufferSize(size + len);

             System.arraycopy(b, off, buf, size, len);

             size += len;

         }

         public final void write(int b) {

             verifyBufferSize(size + 1);

             buf[size++] = (byte) b;

         }

         public void reset() {

             size = 0;

         }

         /**

          * Returns a ByteArrayInputStream for reading back the written data

          */

         public InputStream getInputStream() {

             return new FastByteArrayInputStream(buf, size);

         }

     }

     /**

      * ByteArrayInputStream implementation that does not synchronize methods.

      */

     private static class FastByteArrayInputStream extends InputStream {

         /**

          * Our byte buffer

          */

         protected byte[] buf = null;

         /**

          * Number of bytes that we can read from the buffer

          */

         protected int count = 0;

         /**

          * Number of bytes that have been read from the buffer

          */

         protected int pos = 0;

         public FastByteArrayInputStream(byte[] buf, int count) {

             this.buf = buf;

             this.count = count;

         }

         public final int available() {

             return count - pos;

         }

         public final int read() {

             return (pos < count) ? (buf[pos++] & 0xff) : -1;

         }

         public final int read(byte[] b, int off, int len) {

             if (pos >= count)

                 return -1;

             if ((pos + len) > count)

                 len = (count - pos);

             System.arraycopy(buf, pos, b, off, len);

             pos += len;

             return len;

         }

         public final long skip(long n) {

             if ((pos + n) > count)

                 n = count - pos;

             if (n < 0)

                 return 0;

             pos += n;

             return n;

         }

     }

 }