path: root/bundles/org.eclipse.team.core/src/org/eclipse/team/internal/core/XMLMemento.java

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.team.internal.core;

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

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.team.core.TeamException;
import org.w3c.dom.*;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
 * This class represents the default implementation of the
 * <code>IMemento</code> interface.
 * <p>
 * This class is not intended to be extended by clients.
 * </p>
 * [Note: This class has been copied from org.eclipse.ui to get a quick and
 * dirty xml input/output code. This should be purged once the settings
 * work is complete]
 * @see IMemento
 */
public final class XMLMemento implements IMemento {
	private Document factory;
	private Element element;

	/**
	 * Creates a <code>Document</code> from the <code>Reader</code>
	 * and returns a memento on the first <code>Element</code> for reading
	 * the document.
	 * <p>
	 * Same as calling createReadRoot(reader, null)
	 * </p>
	 * 
	 * @param reader the <code>Reader</code> used to create the memento's document
	 * @return a memento on the first <code>Element</code> for reading the document
	 * @throws <code>WorkbenchException</code> if IO problems, invalid format, or no element.
	 */
	public static XMLMemento createReadRoot(Reader reader) throws TeamException {
		return createReadRoot(reader, null);
	}

	/**
	 * Creates a <code>Document</code> from the <code>Reader</code>
	 * and returns a memento on the first <code>Element</code> for reading
	 * the document.
	 * 
	 * @param reader the <code>Reader</code> used to create the memento's document
	 * @param baseDir the directory used to resolve relative file names
	 * 		in the XML document. This directory must exist and include the
	 * 		trailing separator. The directory format, including the separators,
	 * 		must be valid for the platform. Can be <code>null</code> if not
	 * 		needed.
	 * @return a memento on the first <code>Element</code> for reading the document
	 * @throws <code>WorkbenchException</code> if IO problems, invalid format, or no element.
	 */
	public static XMLMemento createReadRoot(Reader reader, String baseDir) throws TeamException {
		String messageKey = "XMLMemento.noElement"; //$NON-NLS-1$
		Exception exception = null;
		
		try {
			DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
			DocumentBuilder parser = factory.newDocumentBuilder();
			InputSource source = new InputSource(reader);
			if (baseDir != null)
				source.setSystemId(baseDir);
			Document document = parser.parse(source);
			NodeList list = document.getChildNodes();
			for (int i = 0; i < list.getLength(); i++) {
				Node node = list.item(i);
				if (node instanceof Element)
					return new XMLMemento(document, (Element) node);
			}
		} catch (ParserConfigurationException e) {
			exception = e;
			messageKey = "XMLMemento.parserConfigError"; //$NON-NLS-1$
		} catch (IOException e) {
			exception = e;
			messageKey = "XMLMemento.ioError"; //$NON-NLS-1$
		} catch (SAXException e) {
			exception = e;
			messageKey = "XMLMemento.formatError"; //$NON-NLS-1$
		}
		
		String problemText = null;
		if (exception != null)
			problemText = exception.getMessage();
		//if (problemText == null || problemText.length() == 0)
		//	problemText = TeamException.getString(messageKey);
		throw new TeamException(problemText);
	}
	
	/**
	 * Returns a root memento for writing a document.
	 * 
	 * @param type the element node type to create on the document
	 * @return the root memento for writing a document
	 */
	public static XMLMemento createWriteRoot(String type) {
        Document document;
        try {
            document = DocumentBuilderFactory
                            .newInstance()
                            .newDocumentBuilder()
                            .newDocument();
            Element element = document.createElement(type);
            document.appendChild(element);
            return new XMLMemento(document, element);            
        }
        catch (ParserConfigurationException e) {
            throw new Error(e);
        }
	}
	
	/**
	 * Creates a memento for the specified document and element.
	 * <p>
	 * Clients should use <code>createReadRoot</code> and
	 * <code>createWriteRoot</code> to create the initial
	 * memento on a document.
	 * </p>
	 * 
	 * @param document the document for the memento
	 * @param element the element node for the memento
	 */
	public XMLMemento(Document document, Element element) {
		super();
		this.factory = document;
		this.element = element;
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public IMemento createChild(String type) {
		Element child = factory.createElement(type);
		element.appendChild(child);
		return new XMLMemento(factory, child);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public IMemento createChild(String type, String id) {
		Element child = factory.createElement(type);
		child.setAttribute(TAG_ID, id == null ? "" : id); //$NON-NLS-1$
		element.appendChild(child);
		return new XMLMemento(factory, child);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public IMemento copyChild(IMemento child) {
		Element childElement = ((XMLMemento) child).element;
		Element newElement = (Element) factory.importNode(childElement, true);
		element.appendChild(newElement);
		return new XMLMemento(factory, newElement);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public IMemento getChild(String type) {

		// Get the nodes.
		NodeList nodes = element.getChildNodes();
		int size = nodes.getLength();
		if (size == 0)
			return null;

		// Find the first node which is a child of this node.
		for (int nX = 0; nX < size; nX++) {
			Node node = nodes.item(nX);
			if (node instanceof Element) {
				Element element = (Element) node;
				if (element.getNodeName().equals(type))
					return new XMLMemento(factory, element);
			}
		}

		// A child was not found.
		return null;
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public IMemento[] getChildren(String type) {

		// Get the nodes.
		NodeList nodes = element.getChildNodes();
		int size = nodes.getLength();
		if (size == 0)
			return new IMemento[0];

		// Extract each node with given type.
		ArrayList list = new ArrayList(size);
		for (int nX = 0; nX < size; nX++) {
			Node node = nodes.item(nX);
			if (node instanceof Element) {
				Element element = (Element) node;
				if (element.getNodeName().equals(type))
					list.add(element);
			}
		}

		// Create a memento for each node.
		size = list.size();
		IMemento[] results = new IMemento[size];
		for (int x = 0; x < size; x++) {
			results[x] = new XMLMemento(factory, (Element) list.get(x));
		}
		return results;
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public Float getFloat(String key) {
		Attr attr = element.getAttributeNode(key);
		if (attr == null)
			return null;
		String strValue = attr.getValue();
		try {
			return new Float(strValue);
		} catch (NumberFormatException e) {
			TeamPlugin.log(IStatus.ERROR, "Memento problem - Invalid float for key: " //$NON-NLS-1$
			+ key + " value: " + strValue, null); //$NON-NLS-1$
			return null;
		}
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public String getID() {
		return element.getAttribute(TAG_ID);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public Integer getInteger(String key) {
		Attr attr = element.getAttributeNode(key);
		if (attr == null)
			return null;
		String strValue = attr.getValue();
		try {
			return new Integer(strValue);
		} catch (NumberFormatException e) {
			TeamPlugin.log(IStatus.ERROR, "Memento problem - invalid integer for key: " + key //$NON-NLS-1$
			+ " value: " + strValue, null); //$NON-NLS-1$
			return null;
		}
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public String getString(String key) {
		Attr attr = element.getAttributeNode(key);
		if (attr == null)
			return null;
		return attr.getValue();
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public String getTextData() {
		Text textNode = getTextNode();
		if (textNode != null) {
			return textNode.getData();
		} else {
			return null;
		}
	}

	/**
	 * Returns the Text node of the memento. Each memento is allowed only 
	 * one Text node.
	 * 
	 * @return the Text node of the memento, or <code>null</code> if
	 * the memento has no Text node.
	 */
	private Text getTextNode() {
		// Get the nodes.
		NodeList nodes = element.getChildNodes();
		int size = nodes.getLength();
		if (size == 0)
			return null;
		for (int nX = 0; nX < size; nX++) {
			Node node = nodes.item(nX);
			if (node instanceof Text) {
				return (Text) node;
			}
		}
		// a Text node was not found
		return null;
	}

	/**
	 * Places the element's attributes into the document.
	 */
	private void putElement(Element element) {
		NamedNodeMap nodeMap = element.getAttributes();
		int size = nodeMap.getLength();
		for (int i = 0; i < size; i++) {
			Attr attr = (Attr) nodeMap.item(i);
			putString(attr.getName(), attr.getValue());
		}

		NodeList nodes = element.getChildNodes();
		size = nodes.getLength();
		for (int i = 0; i < size; i++) {
			Node node = nodes.item(i);
			if (node instanceof Element) {
				XMLMemento child = (XMLMemento) createChild(node.getNodeName());
				child.putElement((Element) node);
			}
		}
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public void putFloat(String key, float f) {
		element.setAttribute(key, String.valueOf(f));
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public void putInteger(String key, int n) {
		element.setAttribute(key, String.valueOf(n));
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public void putMemento(IMemento memento) {
		putElement(((XMLMemento) memento).element);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public void putString(String key, String value) {
		if (value == null)
			return;
		element.setAttribute(key, value);
	}
	
	/* (non-Javadoc)
	 * Method declared in IMemento.
	 */
	public void putTextData(String data) {
		Text textNode = getTextNode();
		if (textNode == null) {
			textNode = factory.createTextNode(data);
			element.appendChild(textNode);
		} else {
			textNode.setData(data);
		}
	}
	
	/**
	 * Saves this memento's document current values to the
	 * specified writer. 
	 * 
	 * @param writer the writer used to save the memento's document
     * @throws IOException if there is a problem serializing the document to the stream.
	 */
	public void save(Writer writer) throws IOException {
        Result result = new StreamResult(writer);
        Source source = new DOMSource(factory);
        try {
            Transformer transformer = TransformerFactory.newInstance().newTransformer();
            transformer.setOutputProperty(OutputKeys.INDENT, "yes"); //$NON-NLS-1$
            transformer.setOutputProperty(OutputKeys.METHOD, "xml"); //$NON-NLS-1$
            transformer.transform(source, result);            
        }
        catch (TransformerConfigurationException e) {
            throw (IOException) (new IOException().initCause(e));
        }
        catch (TransformerException e) {
            throw (IOException) (new IOException().initCause(e));
        }
	}
}