SmartObjectInputStream.java

/* Copyright (c) 2006-2009 Jan S. Rellermeyer
 * Systems Group,
 * Institute for Pervasive Computing, ETH Zurich.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    - Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *    - 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.
 *    - Neither the name of ETH Zurich nor the names of its contributors may be
 *      used to endorse or promote products derived from this software without
 *      specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS 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 THE COPYRIGHT OWNER OR 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.
 */

package ch.ethz.iks.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;

/**
 * Smart object input stream that is able to deserialize classes which do not
 * implement Serializable. It only rejects classes which have native code parts
 * and the OSGi ServiceReference and ServiceRegistration classes.
 * 
 * @author Jan S. Rellermeyer
 * 
 */
public final class SmartObjectInputStream extends ObjectInputStream {

	private final ObjectInputStream in;

	public SmartObjectInputStream(final InputStream in) throws IOException {
		// implicitly: super();
		// thereby, enableOverride is set
		this.in = new ObjectInputStream(in);
	}

	protected final Object readObjectOverride() throws IOException,
			ClassNotFoundException {

		final byte cat = in.readByte();
		switch (cat) {
		case 0:
			// null
			return null;
		case 1:
			// string serialized object
			// TODO: cache constructors
			try {
				final String type = in.readUTF();
				final Class test = (Class) SmartConstants.idToClass.get(type);
				final Class clazz = test != null ? test : Class.forName(type);
				final Constructor constr = clazz
						.getConstructor(new Class[] { String.class });
				return constr.newInstance(new Object[] { in.readUTF() });
			} catch (final Exception e) {
				e.printStackTrace();
				throw new IOException(e.getMessage());
			}
		case 2:
			// java serialized object
			return in.readObject();
		case 3:
			return readSmartSerializedObject();
		case 4:
			final int length = in.readByte();
			final String clazzName = in.readUTF();
			final Class clazz = Class.forName(clazzName);
			final Object[] array = (Object[]) java.lang.reflect.Array
					.newInstance(clazz, length);
			for (int i = 0; i < length; i++) {
				final byte b = in.readByte();
				if(b == -1) {
					array[i] = null;
				} else {
					array[i] = readSmartSerializedObject();
				}
			}
			return array;
		default:
			throw new IllegalStateException("Unhandled case " + cat); //$NON-NLS-1$
		}
	}

	private Object readSmartSerializedObject() throws IOException, ClassNotFoundException {
		// smart serialized object
		final String clazzName = in.readUTF();

		// TODO: cache this information...
		Class clazz = Class.forName(clazzName);

		try {
			final Constructor constr = clazz.getDeclaredConstructor(null);
			constr.setAccessible(true);
			final Object newInstance = constr.newInstance(null);

			int fieldCount = in.readInt();
			while (fieldCount > -1) {
				for (int i = 0; i < fieldCount; i++) {
					final String fieldName = in.readUTF();
					final Object value = readObjectOverride();
					final Field field = clazz.getDeclaredField(fieldName);

					final int mod = field.getModifiers();
					if (!Modifier.isPublic(mod)) {
						field.setAccessible(true);
					}

					field.set(newInstance, value);
				}
				clazz = clazz.getSuperclass();
				fieldCount = in.readInt();
			}
			return newInstance;
		} catch (final Exception e) {
			e.printStackTrace();
			throw new IOException("Error while deserializing " + clazzName //$NON-NLS-1$
					+ ": " + e.getMessage()); //$NON-NLS-1$
		}
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#read()
	 */
	public final int read() throws IOException {
		return in.read();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#read(byte[], int, int)
	 */
	public final int read(final byte[] buf, final int off, final int len)
			throws IOException {
		return in.read(buf, off, len);
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#available()
	 */
	public final int available() throws IOException {
		return in.available();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#close()
	 */
	public final void close() throws IOException {
		in.close();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readBoolean()
	 */
	public final boolean readBoolean() throws IOException {
		return in.readBoolean();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readByte()
	 */
	public final byte readByte() throws IOException {
		return in.readByte();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readUnsignedByte()
	 */
	public final int readUnsignedByte() throws IOException {
		return in.readUnsignedByte();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readChar()
	 */
	public final char readChar() throws IOException {
		return in.readChar();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readShort()
	 */
	public final short readShort() throws IOException {
		return in.readShort();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readUnsignedShort()
	 */
	public final int readUnsignedShort() throws IOException {
		return in.readUnsignedShort();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readInt()
	 */
	public final int readInt() throws IOException {
		return in.readInt();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readLong()
	 */
	public final long readLong() throws IOException {
		return in.readLong();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readFloat()
	 */
	public final float readFloat() throws IOException {
		return in.readFloat();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readDouble()
	 */
	public final double readDouble() throws IOException {
		return in.readDouble();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readFully(byte[])
	 */
	public final void readFully(final byte[] buf) throws IOException {
		in.readFully(buf);
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readFully(byte[], int, int)
	 */
	public final void readFully(final byte[] buf, final int off, final int len)
			throws IOException {
		in.readFully(buf, off, len);
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#skipBytes(int)
	 */
	public final int skipBytes(final int len) throws IOException {
		return in.skipBytes(len);
	}

	/**
	 * @return String
	 * @throws IOException 
	 * @deprecated
	 */
	public final String readLine() throws IOException {
		return in.readLine();
	}

	/**
	 * 
	 * @see java.io.ObjectInputStream#readUTF()
	 */
	public final String readUTF() throws IOException {
		return in.readUTF();
	}

}