leapcodec.java

java实现的P2P多agent中间件

/**
 * ***************************************************************
 * JADE - Java Agent DEvelopment Framework is a framework to develop
 * multi-agent systems in compliance with the FIPA specifications.
 * Copyright (C) 2000 CSELT S.p.A.
 * 
 * GNU Lesser General Public License
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation,
 * version 2.1 of the License.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 * **************************************************************
 */
package jade.content.lang.leap;

import jade.content.lang.*;
import jade.content.onto.*;
import jade.content.abs.*;
import jade.content.schema.ObjectSchema;
import jade.util.leap.*;
import java.util.Vector;
import java.util.Date;
import java.io.*;

/** 
 * Content language codec for the LEAP language
 * @author Federico Bergenti - Universita` di Parma
 */
public class LEAPCodec extends ByteArrayCodec {
	public static final String NAME = "LEAP";

	private transient ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
	private transient DataOutputStream      outStream = new DataOutputStream(outBuffer);
	private transient Vector             stringReferences = new Vector();
	//#MIDP_EXCLUDE_BEGIN
	private void readObject(java.io.ObjectInputStream oin) throws java.io.IOException, ClassNotFoundException {
		oin.defaultReadObject();
		outBuffer = new ByteArrayOutputStream();
		outStream = new DataOutputStream(outBuffer);
		stringReferences = new Vector();
	}
	//#MIDP_EXCLUDE_END

	// Types
	private static final byte  PRIMITIVE = 0;
	private static final byte  AGGREGATE = 1;
	private static final byte  CONTENT_ELEMENT_LIST = 2;
	private static final byte  OBJECT = 3;

	// Markers for structured types
	private static final byte  ELEMENT = 4;
	private static final byte  END = 5;

	// Primitive types
	private static final byte  STRING = 6;
	private static final byte  BOOLEAN = 7;
	private static final byte  INTEGER = 8;
	private static final byte  LONG = 9;
	private static final byte  FLOAT = 10;
	private static final byte  DOUBLE = 11;
	private static final byte  DATE = 12;
	private static final byte  BYTE_SEQUENCE = 13;

	// Modifiers 
	private static final byte  MODIFIER = (byte) 0x10; // Only bit five set to 1
	private static final byte  UNMODIFIER = (byte) 0xEF; // Only bit five cleared to 1

	/* LEAP Language operators
    public static final String INSTANCEOF = "INSTANCEOF";
    public static final String INSTANCEOF_ENTITY = "entity";
    public static final String INSTANCEOF_TYPE = "type";

    public static final String IOTA = "IOTA";
	 */

	/**
	 * Construct a LEAPCodec object i.e. a Codec for the LEAP language
	 */
	public LEAPCodec() {
		super(NAME);
	}

	/**
	 * Encodes an abstract descriptor holding a content element
	 * into a byte array.
	 * @param content the content as an abstract descriptor.
	 * @return the content as a byte array.
	 * @throws CodecException
	 */
	public synchronized byte[] encode(AbsContentElement content) throws CodecException {
		try {
			outBuffer.reset();
			stringReferences.removeAllElements();
			write(outStream, content);

			return outBuffer.toByteArray();
		} 
		catch (Throwable t) {
			throw new CodecException("Error encoding content", t);
		} 
	} 

	/**
	 * Encodes a content into a byte array.
	 * @param ontology the ontology 
	 * @param content the content as an abstract descriptor.
	 * @return the content as a byte array.
	 * @throws CodecException
	 */
	public byte[] encode(Ontology ontology, AbsContentElement content) throws CodecException {
		return encode(content);
	} 

	/**
	 * Decodes the content to an abstract descriptor.
	 * @param content the content as a byte array.
	 * @return the content as an abstract description.
	 * @throws CodecException
	 */
	public AbsContentElement decode(byte[] content) throws CodecException {
		throw new CodecException("Not supported");
	} 

	/**
	 * Decodes the content to an abstract description.
	 * @param ontology the ontology.
	 * @param content the content as a byte array.
	 * @return the content as an abstract description.
	 * @throws CodecException
	 */
	public synchronized AbsContentElement decode(Ontology ontology, byte[] content) throws CodecException {
		if (content.length == 0) {
			return null;
		}
		try {
			ByteArrayInputStream inpBuffer = new ByteArrayInputStream(content);
			DataInputStream      inpStream = new DataInputStream(inpBuffer);

			stringReferences.removeAllElements();
			AbsObject obj = read(inpStream, ontology);
			inpStream.close();
			return (AbsContentElement) obj;
		} 
		catch (Throwable t) {
			throw new CodecException("Error decoding content", t);
		} 
	} 

	/**
	 * Synchronized so that it can possibly be executed by different threads
	 */
	private void write(DataOutputStream stream, AbsObject abs) throws Throwable {
		// PRIMITIVE
		if (abs instanceof AbsPrimitive) {
			//stream.writeByte(PRIMITIVE);

			Object obj = ((AbsPrimitive) abs).getObject();

			if (obj instanceof String) {
				writeString(stream, STRING, (String) obj);
			} 
			else if (obj instanceof Boolean) {
				stream.writeByte(BOOLEAN);
				stream.writeBoolean(((Boolean) obj).booleanValue());
			} 
			else if (obj instanceof Integer) {
				stream.writeByte(INTEGER);
				stream.writeInt(((Integer) obj).intValue());
			} 
			else if (obj instanceof Long) {
				stream.writeByte(LONG);
				stream.writeLong(((Long) obj).longValue());
			} 
			//#MIDP_EXCLUDE_BEGIN
			else if (obj instanceof Float) {
				stream.writeByte(FLOAT);
				stream.writeFloat(((Float) obj).floatValue());
			} 
			else if (obj instanceof Double) {
				stream.writeByte(DOUBLE);
				stream.writeDouble(((Double) obj).doubleValue());
			} 
			//#MIDP_EXCLUDE_END
			else if (obj instanceof Date) {
				stream.writeByte(DATE);
				stream.writeLong(((Date) obj).getTime());
			} 
			else if (obj instanceof byte[]) {
				stream.writeByte(BYTE_SEQUENCE);
				byte[] b = (byte[]) obj;
				stream.writeInt(b.length);
				stream.write(b, 0, b.length);
			} 

			return;
		} 

		// AGGREGATE
		if (abs instanceof AbsAggregate) {
			writeString(stream, AGGREGATE, abs.getTypeName());

			AbsAggregate aggregate = (AbsAggregate) abs;

			for (int i = 0; i < aggregate.size(); i++) {
				stream.writeByte(ELEMENT);
				write(stream, aggregate.get(i));
			} 

			stream.writeByte(END);

			return;
		} 

		// CONTENT_ELEMENT_LIST
		if (abs instanceof AbsContentElementList) {
			stream.writeByte(CONTENT_ELEMENT_LIST);

			AbsContentElementList acel = (AbsContentElementList) abs;

			for (int i = 0; i < acel.size(); i++) {
				stream.writeByte(ELEMENT);
				write(stream, acel.get(i));
			} 

			stream.writeByte(END);

			return;
		} 

		// If we get here it must be a complex OBJECT
		writeString(stream, OBJECT, abs.getTypeName());

		String[] names = abs.getNames();

		for (int i = 0; i < abs.getCount(); i++) {
			writeString(stream, ELEMENT, names[i]);
			AbsObject child = abs.getAbsObject(names[i]);
			write(stream, child);
		} 

		stream.writeByte(END);
	} 

	/**
	 * Synchronized so that it can possibly be executed by different threads
	 */
	private synchronized AbsObject read(DataInputStream stream, 
			Ontology ontology) throws Throwable {
		byte type = stream.readByte();

		// PRIMITIVE
		//if (type == PRIMITIVE) {
		//    byte         primitiveType = stream.readByte();
		//    AbsPrimitive abs = null;

		if ((type&UNMODIFIER) == STRING) {
			return AbsPrimitive.wrap(readString(stream, type));
		} 
		if (type == BOOLEAN) {
			boolean value = stream.readBoolean();
			return AbsPrimitive.wrap(value);
		} 
		if (type == INTEGER) {
			int value = stream.readInt();
			return AbsPrimitive.wrap(value);
		} 
		if (type == LONG) {
			long value = stream.readLong();
			return AbsPrimitive.wrap(value);
		} 
		//#MIDP_EXCLUDE_BEGIN
		if (type == FLOAT) {
			float value = stream.readFloat();
			return AbsPrimitive.wrap(value);
		} 
		if (type == DOUBLE) {
			double value = stream.readDouble();
			return AbsPrimitive.wrap(value);
		} 
		//#MIDP_EXCLUDE_END
		if (type == DATE) {
			long value = stream.readLong();
			return AbsPrimitive.wrap(new Date(value));
		} 
		if (type == BYTE_SEQUENCE) {
			byte[] value = new byte[stream.readInt()];
			stream.read(value, 0, value.length);
			return AbsPrimitive.wrap(value);
		} 

		//return abs;
		//} 

		// AGGREGATE
		if ((type&UNMODIFIER) == AGGREGATE) {
			String typeName = readString(stream, type);
			AbsAggregate abs = new AbsAggregate(typeName);
			byte         marker = stream.readByte();

			do {
				if (marker == ELEMENT) {
					AbsObject elementValue = read(stream, ontology);

					if (elementValue != null) {
						try {
							abs.add((AbsTerm) elementValue);
						}
						catch (ClassCastException cce) {
							throw new CodecException("Non term element in aggregate"); 
						}
					} 

					marker = stream.readByte();
				} 
			} 
			while (marker != END);

			return abs;
		} 

		// CONTENT_ELEMENT_LIST
		if (type == CONTENT_ELEMENT_LIST) {
			AbsContentElementList abs = new AbsContentElementList();
			byte                  marker = stream.readByte();

			do {
				if (marker == ELEMENT) {
					AbsObject elementValue = read(stream, ontology);

					if (elementValue != null) {
						try {
							abs.add((AbsContentElement) elementValue);
						}
						catch (ClassCastException cce) {
							throw new CodecException("Non content-element element in content-element-list"); 
						}
					} 

					marker = stream.readByte();
				} 
			} 
			while (marker != END);

			return abs;
		} 

		// If we get here it must be a complex OBJECT
		String typeName = readString(stream, type);
		// DEBUG System.out.println("Type is "+typeName);
		ObjectSchema schema = ontology.getSchema(typeName);
		// DEBUG System.out.println("Schema is "+schema);
		AbsObject    abs = schema.newInstance();

		byte marker = stream.readByte();

		do {
			if ((marker&UNMODIFIER) == ELEMENT) {
				String    attributeName = readString(stream, marker);
				AbsObject attributeValue = read(stream, ontology);

				if (attributeValue != null) {
					AbsHelper.setAttribute(abs, attributeName, attributeValue);
				} 

				marker = stream.readByte();
			} 
		} 
		while (marker != END);

		return abs;
	} 

	private final void writeString(DataOutputStream stream, byte tag, String s) throws Throwable {
		int index = stringReferences.indexOf(s);
		if (index >= 0) {
			// Write the tag modified and just put the index
			//System.out.println("String "+s+" already encoded");
			stream.writeByte(tag|MODIFIER);
			stream.writeByte(index);
		}
		else {
			stream.writeByte(tag);
			stream.writeUTF(s);
			if ((s.length() > 1) && (stringReferences.size() < 256)) {
				stringReferences.addElement(s);
			}
		}
	}

	private final String readString(DataInputStream stream, byte tag) throws Throwable {
		String s = null;
		if ((tag&MODIFIER) != 0) {
			int index = stream.readUnsignedByte();
			if (index < stringReferences.size()) {
				s= (String) stringReferences.elementAt(index);
			}
		}
		else {
			s = stream.readUTF();
			if ((s.length() > 1) && (stringReferences.size() < 256)) {
				stringReferences.addElement(s);
			}
		}
		return s;
	}
}