documentserializableutilities.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: DocumentSerializableUtilities.java,v 1.8 2006/06/19 18:27:35 bondolo Exp $
 */

package net.jxta.util.documentSerializable;

import net.jxta.document.*;
import net.jxta.exception.*;
import net.jxta.util.*;

import java.util.*;
import java.io.*;

/**
 **/
public class DocumentSerializableUtilities {
	// Fix-Me: I didn't implement byte, short or float
	// Fix-Me: I didn't implement arrays, ie addInt(Element element, String tagName, int values[]), etc

	/**
	 * Creates a Structured XML Document containing the serialized object
	 *
	 * @return	The created Document
 	 * @throws DocumentSerializationException if Unable to parse the serialized object.
	 */	
	public static XMLDocument createStructuredXmlDocument(String docType, DocumentSerializable documentSerializable) throws DocumentSerializationException {
			XMLDocument xmlDoc =(XMLDocument) StructuredDocumentFactory.newStructuredDocument(MimeMediaType.XMLUTF8, docType);
			documentSerializable.serializeTo(xmlDoc);
			return xmlDoc;
	}

	/**
	 * Deeply copy an element into another element
	 *
	 * @param toElement The target Element
	 * @param fromElement The source Element
	 */	
	public static void copyChildren(Element toElement, Element fromElement) {
		// for now ... a quicky use of another utility

		StructuredDocument intoDoc = toElement.getRoot();
		StructuredDocumentUtils.copyChildren(intoDoc, toElement, fromElement);
	}

	/**
	 *  Add an Element with the specified tagname and value (converted to a String)
	 *
	 * @param element Parent Element that the new child element will be added to
	 * @param tagName TagName to be used for the created Child Element
	 * @param documentSerializable This value will be serialized into the created child element
\ 	 * @throws DocumentSerializationException if Unable to serialized object.
	 **/
	public static void addDocumentSerializable(Element element, String tagName, DocumentSerializable documentSerializable)  throws DocumentSerializationException {
		StructuredDocument structuredDocument = (StructuredDocument) element.getRoot();
		Element childElement = structuredDocument.createElement(tagName);
		element.appendChild(childElement);
		documentSerializable.serializeTo(childElement);
	}

	/**
	 *  Create an object from its Document Serialized components
	 *
	 * @param element The relative root element of a Document Serialized Object
	 * @param clazz The Class of the resurrected object (must implement DocumentSerializable and have a public no-arg constructor)
	 * @return An object of type 'clazz'
 	 * @throws DocumentSerializationException if Unable to parse the serialized object.
	 **/
	public static DocumentSerializable getDocumentSerializable(Element element, Class clazz) throws DocumentSerializationException {
		try {
			return getDocumentSerializable(element, (DocumentSerializable) clazz.newInstance());
		} catch (DocumentSerializationException e) {
			throw e;
		} catch (Exception e) {
			throw new DocumentSerializationException("Class must have a public no-arg constructor", e);
		}
	}
	
	/**
	 *  Initialize an object from its Document Serialized components
	 *
	 * @param element The relative root element of a Document Serialized Object
	 * @param documentSerializable The object that will be populated from the Element
	 * @return The same parameter passed to it 'documentSerializable'
 	 * @throws DocumentSerializationException if Unable to parse the serialized object.
	 **/
	public static DocumentSerializable getDocumentSerializable(Element element, DocumentSerializable documentSerializable) throws DocumentSerializationException {
		documentSerializable.initializeFrom(element);
		return documentSerializable;
	}

	/**
	 *  Create an object from its Document Serialized components
	 *
	 * @param element The Parent element which has a child Element with the serialized value
	 * @param tagName The tagname of the element that contains the relative root element of a Document Serialized Object
	 * @param clazz The Class of the resurrected object (must implement DocumentSerializable and have a public no-arg constructor)
	 * @return An object of type 'clazz'
 	 * @throws DocumentSerializationException if Unable to parse the serialized object.
	 **/
	public static DocumentSerializable getDocumentSerializable(Element element, String tagName, Class clazz) throws DocumentSerializationException {
		Element childElement = getChildElement(element, tagName);
		
		if (childElement != null)
			return getDocumentSerializable(childElement, clazz);
		else
			return null;
	}	

	
	/**
	 *  Create a copy of any Document Serializable object.
	 *  
	 *  This is done by serializing and then deserializing the object (ie not very efficient)
	 *
	 * @param documentSerializable The Object to be copied
	 * @return An copy of the presented object
 	 * @throws DocumentSerializationException if Unable to serialize or parse object.
	 **/
	public static DocumentSerializable copyDocumentSerializable(DocumentSerializable documentSerializable) throws DocumentSerializationException {
		StructuredDocument structuredDocument = createStructuredXmlDocument("temp", documentSerializable);
		return getDocumentSerializable(structuredDocument, documentSerializable.getClass());
	}


	/**
	 *  Create a child element of the specified tagName
	 *  
	 *  This is done by serializing and then deserializing the object (ie not very efficient)
	 *
	 * @param element The Parent Element
	 * @param tagName The Tag Name for the new Element
	 * @return The created Element
	 **/
	public static Element createChildElement(Element element, String tagName) {
		StructuredDocument structuredDocument = (StructuredDocument) element.getRoot();
		Element childElement = structuredDocument.createElement(tagName);
		element.appendChild(childElement);
		return childElement;
	}

	/**
	 *  Get a child element of the specified tagName
	 *  
	 *  This is done by serializing and then deserializing the object (ie not very efficient)
	 *
	 * @param element The Parent Element
	 * @param tagName The Tag Name for the new Element
	 * @return The found Element
	 **/
	public static Element getChildElement(Element element, String tagName) {
		Enumeration e = element.getChildren(tagName);
		
		if (e.hasMoreElements())
			return (Element) e.nextElement();
		else
			return null;
	}

	/**
	 *  Add an Element with the specified tagname and value (converted to a String)
	 *
	 * @param element Parent Element that the new element will be added to
	 * @param tagName TagName to be used for the created Child Element
	 * @param value The value that will be stored in the Element as a String
	 **/	 
	public static void addInt(Element element, String tagName, int value) {
		StructuredDocument structuredDocument = (StructuredDocument) element.getRoot();
		Element childElement = structuredDocument.createElement(tagName, Integer.toString(value));
		element.appendChild(childElement);
	}



	/**
	 *  Get  the value of an element converted from a String
	 *
	 * @param element Element that contains the value
	 * @return the value converted from a String
	 **/
	public static int getInt(Element element) {
		return Integer.parseInt((String) element.getValue());
	}
	
	/**
	 *  Get the value of a Child Element 
	 *
	 * @param element The Parant Element
	 * @param tagName The Tag Name of the Child Element that will contain the value
	 * @param defaultValue The return value if there is no Child Element with that Tag Name
	 * @return the value converted from a String
	 **/
	public static int getInt(Element element, String tagName, int defaultValue) {
		Element childElement = getChildElement(element, tagName);
		
		if (childElement != null)
			return getInt(childElement);
		else
			return defaultValue;
	}	
		
	/**
	 *  Add an Element with the specified tagname and value (converted to a String)
	 *
	 * @param element Parent Element that the new element will be added to
	 * @param tagName TagName to be used for the created Child Element
	 * @param value The value that will be stored in the Element as a String
	 **/
	public static void addLong(Element element, String tagName, long value) {
		StructuredDocument structuredDocument = (StructuredDocument) element.getRoot();
		Element childElement = structuredDocument.createElement(tagName, Long.toString(value));
		element.appendChild(childElement);
	}

	/**
	 *  Get  the value of an element converted from a String
	 *
	 * @param element Element that contains the value
	 * @return the value converted from a String
	 **/
	public static long getLong(Element element) {
		return Long.parseLong((String) element.getValue());
	}