bundles/org.eclipse.wst.xsl.ui/src/org/eclipse/wst/xsl/ui/internal/contentassist/XSLContentAssistProcessor.java - sourceediting/webtools.sourceediting.xsl - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008 Standards for Technology in Automotive Retail and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     David Carver - STAR - bug 213849 - initial API and implementation
  *     David Carver - STAR - bug 230958 - refactored to fix bug with getting
  *                                        the DOM Document for the current editor
  *
  *******************************************************************************/
 package org.eclipse.wst.xsl.ui.internal.contentassist;

 import java.util.ArrayList;
 import java.util.List;

 import javax.xml.transform.TransformerException;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
 import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegion;
 import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegionList;
 import org.eclipse.wst.sse.ui.internal.contentassist.ContentAssistUtils;
 import org.eclipse.wst.sse.ui.internal.contentassist.CustomCompletionProposal;
 import org.eclipse.wst.xml.core.internal.provisional.document.IDOMAttr;
 import org.eclipse.wst.xml.core.internal.provisional.document.IDOMNode;
 import org.eclipse.wst.xml.core.internal.regions.DOMRegionContext;
 import org.eclipse.wst.xml.ui.internal.contentassist.ContentAssistRequest;
 import org.eclipse.wst.xml.ui.internal.contentassist.XMLContentAssistProcessor;
 import org.eclipse.wst.xml.xpath.core.internal.parser.XPathParser;
 import org.eclipse.wst.xml.xpath.core.util.XSLTXPathHelper;
 import org.eclipse.wst.xml.xpath.ui.internal.contentassist.XPathTemplateCompletionProcessor;
 import org.eclipse.wst.xml.xpath.ui.internal.templates.TemplateContextTypeIdsXPath;
 import org.eclipse.wst.xsl.core.XSLCore;
 import org.eclipse.wst.xsl.core.internal.XSLCorePlugin;
 import org.eclipse.wst.xsl.core.internal.util.StructuredDocumentUtil;
 import org.eclipse.wst.xsl.ui.internal.XSLUIPlugin;
 import org.eclipse.wst.xsl.ui.internal.util.XSLPluginImageHelper;
 import org.eclipse.wst.xsl.ui.internal.util.XSLPluginImages;
 import org.w3c.dom.Element;
 import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;

 /**
  * The XSL Content Assist Processor provides content assistance for various
  * attributes values within the XSL Editor. This includes support for xpaths on
  * select statements as well as on test and match attributes.
  *
  * @author David Carver
  *
  *
  *
  */
 public class XSLContentAssistProcessor extends XMLContentAssistProcessor
 		implements IPropertyChangeListener {

 	private static final String ATTR_SELECT = "select"; //$NON-NLS-1$
 	private static final String ATTR_TEST = "test"; //$NON-NLS-1$
 	private static final String ATTR_MATCH = "match"; //$NON-NLS-1$
 	/**
 	 * Retrieve all global variables in the stylesheet.
 	 */
 	private static final String XPATH_GLOBAL_VARIABLES = "/xsl:stylesheet/xsl:variable"; //$NON-NLS-1$

 	/**
 	 * Retrieve all global parameters in the stylesheet.
 	 */
 	private static final String XPATH_GLOBAL_PARAMS = "/xsl:stylesheet/xsl:param"; //$NON-NLS-1$

 	/**
 	 * Limit selection of variables to those that are in the local scope.
 	 */
 	private static final String XPATH_LOCAL_VARIABLES = "ancestor::xsl:template/descendant::xsl:variable"; //$NON-NLS-1$

 	/**
 	 * Limit selection of params to those that are in the local scope.
 	 */
 	private static final String XPATH_LOCAL_PARAMS = "ancestor::xsl:template/descendant::xsl:param"; //$NON-NLS-1$

 	private XPathTemplateCompletionProcessor fTemplateProcessor = null;
 	private List<String> fTemplateContexts = new ArrayList<String>();
 	private static final byte[] XPATH_LOCK = new byte[0];

 	/**
 	 * The XSL Content Assist Processor handles XSL specific functionality for
 	 * content assistance. It leverages several XPath selection variables to
 	 * help with the selection of elements and template names.
 	 *
 	 */
 	public XSLContentAssistProcessor() {
 		super();
 	}


 	/**
 	 * TODO: Add Javadoc
 	 *
 	 * @param textViewer
 	 * @param documentPosition
 	 * @return
 	 *
 	 * @see org.eclipse.wst.xml.ui.contentassist.AbstractContentAssistProcessor#
 	 * 	computeCompletionProposals(org.eclipse.jface.text.ITextViewer, int)
 	 */
 	@Override
 	public ICompletionProposal[] computeCompletionProposals(
 			ITextViewer textViewer, int documentPosition) {
 		fTemplateContexts.clear();
 		return super.computeCompletionProposals(textViewer, documentPosition);
 	}


 	/**
 	 * Adds Attribute proposals based on the element and the attribute where the
 	 * content proposal was instantiated.
 	 *
 	 * @param contentAssistRequest
 	 * 		Content Assist Request that initiated the proposal request
 	 *
 	 */
 	@Override
 	protected void addAttributeValueProposals(ContentAssistRequest contentAssistRequest) {
 		super.addAttributeValueProposals(contentAssistRequest);

 		String attributeName = getAttributeName(contentAssistRequest);
 		Element rootElement = contentAssistRequest.getNode().getOwnerDocument().getDocumentElement();

 		if (attributeName != null) {
 			int offset = contentAssistRequest.getReplacementBeginPosition() + 1;

 			addAttributeValueOfProposals(contentAssistRequest, contentAssistRequest.getNode().getNamespaceURI(), rootElement, offset);

 			if (XSLCore.isXSLNamespace((IDOMNode)contentAssistRequest.getNode())) {
 				addSelectAndTestProposals(contentAssistRequest, attributeName, rootElement, offset);
 				addMatchProposals(contentAssistRequest, attributeName,	offset);
 			}
 		}
 	}

 	private void addMatchProposals(ContentAssistRequest contentAssistRequest, String attributeName, int offset) {
 		if (attributeName.equals(ATTR_MATCH)) {
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);
 		}
 	}

 	private void addSelectAndTestProposals(
 			ContentAssistRequest contentAssistRequest, String attributeName, Element rootElement, int offset) {
 		if (attributeName.equals(ATTR_SELECT) || attributeName.equals(ATTR_TEST)) {
 			addGlobalProposals(rootElement, contentAssistRequest, offset);
 			addLocalProposals(contentAssistRequest.getNode(), contentAssistRequest, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);
 		}
 	}

 	private void addAttributeValueOfProposals(
 			ContentAssistRequest contentAssistRequest, String namespace, Element rootElement, int offset) {
 		if (contentAssistRequest.getMatchString().contains("{")) {
 			addGlobalProposals(rootElement, contentAssistRequest, contentAssistRequest.getReplacementBeginPosition());
 			addLocalProposals(contentAssistRequest.getNode(), contentAssistRequest,
 					          contentAssistRequest.getReplacementBeginPosition());
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
 			addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);

 		}
 	}

 	private void addLocalProposals(Node xpathnode,
 			ContentAssistRequest contentAssistRequest, int offset) {
 		addVariablesProposals(XPATH_LOCAL_VARIABLES, xpathnode,
 				contentAssistRequest, offset);
 		addVariablesProposals(XPATH_LOCAL_PARAMS, xpathnode,
 				contentAssistRequest, offset);
 	}

 	private void addGlobalProposals(Node xpathnode,
 			ContentAssistRequest contentAssistRequest, int offset) {
 		addVariablesProposals(XPATH_GLOBAL_VARIABLES, xpathnode,
 				contentAssistRequest, offset);
 		addVariablesProposals(XPATH_GLOBAL_PARAMS, xpathnode,
 				contentAssistRequest, offset);
 	}

 	/**
 	 * Adds Parameter and Variables as proposals. This
 	 * information is selected based on the XPath statement that is sent to it
 	 * and the input Node passed. It uses a custom composer to XSL Variable
 	 * proposal.
 	 *
 	 * @param xpath
 	 * @param xpathnode
 	 * @param contentAssistRequest
 	 * @param offset
 	 */
 	private void addVariablesProposals(String xpath, Node xpathnode,
 			ContentAssistRequest contentAssistRequest, int offset) {
 		synchronized (XPATH_LOCK) {
 			try {
 				NodeList nodes = XSLTXPathHelper.selectNodeList(xpathnode, xpath);
 				int startLength = getCursorPosition() - offset;

 				if (hasNodes(nodes)) {
 					for (int nodecnt = 0; nodecnt < nodes.getLength(); nodecnt++) {
 						Node node = nodes.item(nodecnt);
 						String variableName = "$" + node.getAttributes().getNamedItem("name").getNodeValue(); //$NON-NLS-1$ //$NON-NLS-2$

 						CustomCompletionProposal proposal = new CustomCompletionProposal(
 								variableName, offset, 0, startLength + variableName.length(),
 								XSLPluginImageHelper.getInstance().getImage(XSLPluginImages.IMG_VARIABLES),
 								variableName, null, null, 0);
 						contentAssistRequest.addProposal(proposal);
 					}
 				}

 			} catch (TransformerException ex) {
 				XSLUIPlugin.log(ex);
 			}
 		}
 	}

 	/**
 	 * Checks to make sure that the NodeList has data
 	 * @param nodes A NodeList object
 	 * @return True if has data, false if empty
 	 */
 	private boolean hasNodes(NodeList nodes) {
 		return nodes != null && nodes.getLength() > 0;
 	}

 	/**
 	 * Get the cursor position within the Text Viewer
 	 * @return An int value containing the cursor position
 	 */
 	private int getCursorPosition() {
 		return fTextViewer.getTextWidget().getCaretOffset();
 	}

 	/**
 	 * Adds XPath related templates to the list of proposals
 	 *
 	 * @param contentAssistRequest
 	 * @param context
 	 * @param startOffset
 	 */
 	private void addTemplates(ContentAssistRequest contentAssistRequest,
 			String context, int startOffset) {
 		if (contentAssistRequest == null) {
 			return;
 		}

 		// if already adding template proposals for a certain context type, do
 		// not add again
 		if (!fTemplateContexts.contains(context)) {
 			fTemplateContexts.add(context);
 			boolean useProposalList = !contentAssistRequest.shouldSeparate();

 			if (getTemplateCompletionProcessor() != null) {
 				getTemplateCompletionProcessor().setContextType(context);
 				ICompletionProposal[] proposals = getTemplateCompletionProcessor()
 						.computeCompletionProposals(fTextViewer, startOffset);
 				for (int i = 0; i < proposals.length; ++i) {
 					if (useProposalList) {
 						contentAssistRequest.addProposal(proposals[i]);
 					} else {
 						contentAssistRequest.addMacro(proposals[i]);
 					}
 				}
 			}
 		}
 	}

 	private XPathTemplateCompletionProcessor getTemplateCompletionProcessor() {
 		if (fTemplateProcessor == null) {
 			fTemplateProcessor = new XPathTemplateCompletionProcessor();
 		}
 		return fTemplateProcessor;
 	}

 	/**
 	 * Gets the attribute name that the content assist was triggered on.
 	 *
 	 * @param contentAssistRequest
 	 * @return
 	 */
 	private String getAttributeName(ContentAssistRequest contentAssistRequest) {
 		IStructuredDocumentRegion open = ((IDOMNode)contentAssistRequest.getNode()).getFirstStructuredDocumentRegion();
 		ITextRegionList openRegions = open.getRegions();
 		int i = openRegions.indexOf(contentAssistRequest.getRegion());
 		if (i >= 0) {

 			ITextRegion nameRegion = null;
 			while (i >= 0) {
 				nameRegion = openRegions.get(i--);
 				if (nameRegion.getType() == DOMRegionContext.XML_TAG_ATTRIBUTE_NAME) {
 					break;
 				}
 			}

 			// String attributeName = nameRegion.getText();
 			return open.getText(nameRegion);
 		}
 		return null;
 	}

 	/**
 	 * Get the Match String.  This is typically the string-before the current
 	 * offset position.   For a standard XML Region this is calculated from the
 	 * beginning of the region (i.e. element, attribute, attribute value, etc.
 	 * For XSL, an additional check has to be made to determine if we are parsing
 	 * within an XPath region and where we are in the XPath region, as different
 	 * content assistance can be made available depending on where we are at.  This
 	 * primarily affects TEST, and SELECT attributes.
 	 * @param parent
 	 * @param aRegion
 	 * @param offset
 	 * @return
 	 */
 	@Override
 	protected String getMatchString(IStructuredDocumentRegion parent, ITextRegion aRegion, int offset) {
 		String emptyString = "";

 		if (isMatchStringEmpty(parent, aRegion, offset)) {
 			return emptyString; //$NON-NLS-1$
 		}

 		IDOMNode currentNode = (IDOMNode) ContentAssistUtils.getNodeAt(super.fTextViewer, offset);

 		IDOMAttr attributeNode = isXPathRegion(currentNode, aRegion, offset);
 		if (attributeNode != null) {
 			String temp = extractXPathMatchString(attributeNode, aRegion, offset);
 			return temp;
 		}


 		if (hasXMLMatchString(parent, aRegion, offset)) {
 			return extractXMLMatchString(parent, aRegion, offset);
 		}
 		// This is here for saftey reasons.
 		return emptyString;
 	}

 	protected String extractXPathMatchString(IDOMAttr node, ITextRegion aRegion, int offset) {
 		if (node.getValue().length() == 0)	return "";

 		int nodeOffset = node.getValueRegionStartOffset();
 		int column = offset - node.getValueRegionStartOffset();
 		XPathParser parser = new XPathParser(node.getValue());
 		int tokenStart = parser.getTokenStartOffset(1, column);

 		if (tokenStart == column) {
 			return "";
 		}

 		return node.getValue().substring(tokenStart - 1, column - 1);
 	}

 	protected IDOMAttr isXPathRegion(IDOMNode currentNode, ITextRegion aRegion, int offset) {
 		if (XSLCore.isXSLNamespace(currentNode)) {
 			return getXPathNode(currentNode, aRegion);
 		}

 		return null;
 	}

 	protected IDOMAttr getXPathNode(Node node, ITextRegion aRegion) {
 		if (node.hasAttributes()) {
 			if (hasAttributeAtTextRegion(ATTR_SELECT, node.getAttributes(), aRegion)) {
 				return this.getAttributeAtTextRegion(ATTR_SELECT, node.getAttributes(), aRegion);
 			}

 			if (hasAttributeAtTextRegion(ATTR_TEST, node.getAttributes(), aRegion)) {
 				return this.getAttributeAtTextRegion(ATTR_TEST, node.getAttributes(), aRegion);
 			}

 		}
 		return null;
 	}

 	protected boolean hasAttributeAtTextRegion(String attrName, NamedNodeMap nodeMap, ITextRegion aRegion) {
 		IDOMAttr attrNode = (IDOMAttr) nodeMap.getNamedItem(attrName);
 		return attrNode != null && attrNode.getValueRegion().getStart() == aRegion.getStart();
 	}

 	protected IDOMAttr getAttributeAtTextRegion(String attrName, NamedNodeMap nodeMap, ITextRegion aRegion) {
 		IDOMAttr node = (IDOMAttr) nodeMap.getNamedItem(attrName);
 		if (node != null && node.getValueRegion().getStart() == aRegion.getStart()) {
 			return node;
 		}
 		return null;
 	}


 	/**
 	 * An XML Match string is extracted starting from the beginning of the
 	 * region to the current offset.
 	 * @param parent
 	 * @param aRegion
 	 * @param offset
 	 * @return
 	 */
 	protected String extractXMLMatchString(IStructuredDocumentRegion parent,
 			ITextRegion aRegion, int offset) {
 		return parent.getText(aRegion).substring(0, offset - parent.getStartOffset(aRegion));
 	}

 	protected boolean hasXMLMatchString(IStructuredDocumentRegion parent,
 			ITextRegion aRegion, int offset) {
 		return regionHasData(parent, aRegion) && isOffsetAfterStart(parent, aRegion, offset);
 	}

 	protected boolean isOffsetAfterStart(IStructuredDocumentRegion parent,
 			ITextRegion aRegion, int offset) {
 		return parent.getStartOffset(aRegion) < offset;
 	}

 	protected boolean regionHasData(IStructuredDocumentRegion parent,
 			ITextRegion aRegion) {
 		return parent.getText(aRegion).length() > 0;
 	}

 	protected boolean isXMLContentRegion(String regionType) {
 		return regionType == DOMRegionContext.XML_CONTENT;
 	}

 	protected boolean isOffsetAfterEndOffset(IStructuredDocumentRegion parent,
 			ITextRegion aRegion, int offset) {
 		return offset > getRegionEndOffset(parent, aRegion);
 	}

 	protected int getRegionEndOffset(IStructuredDocumentRegion parent,
 			ITextRegion aRegion) {
 		return parent.getStartOffset(aRegion) + aRegion.getTextLength();
 	}

 	protected boolean isXMLTagOpen(String regionType) {
 		return regionType == DOMRegionContext.XML_TAG_OPEN;
 	}

 	protected boolean isAttributeEqualsRegion(String regionType) {
 		return regionType == DOMRegionContext.XML_TAG_ATTRIBUTE_EQUALS;
 	}

 	protected boolean isMatchStringEmpty(IStructuredDocumentRegion parent, ITextRegion aRegion, int offset) {
 		return isRegionNull(aRegion) ||
 		       isCloseRegion(aRegion) ||
 		       isAttributeEqualsRegion(aRegion.getType()) ||
 		       isXMLTagOpen(aRegion.getType()) ||
 		       isOffsetAfterEndOffset(parent, aRegion, offset) ||
 		       isXMLContentRegion(aRegion.getType());
 	}

 	protected boolean isRegionNull(ITextRegion aRegion) {
 		return aRegion == null;
 	}

 	@Override
 	protected ContentAssistRequest computeAttributeValueProposals(int documentPosition, String matchString, ITextRegion completionRegion, IDOMNode nodeAtOffset, IDOMNode node) {
 		ContentAssistRequest contentAssistRequest = null;
 		IStructuredDocumentRegion sdRegion = getStructuredDocumentRegion(documentPosition);
 		if ((documentPosition > sdRegion.getStartOffset(completionRegion) + completionRegion.getTextLength()) && (sdRegion.getStartOffset(completionRegion) + completionRegion.getTextLength() != sdRegion.getStartOffset(completionRegion) + completionRegion.getLength())) {
 			// setup to add a new attribute at the documentPosition
 			IDOMNode actualNode = (IDOMNode) node.getModel().getIndexedRegion(sdRegion.getStartOffset(completionRegion));
 			contentAssistRequest = newContentAssistRequest(actualNode, actualNode, sdRegion, completionRegion, documentPosition, 0, matchString);
 			addAttributeNameProposals(contentAssistRequest);
 			if ((actualNode.getFirstStructuredDocumentRegion() != null) && !actualNode.getFirstStructuredDocumentRegion().isEnded()) {
 				addTagCloseProposals(contentAssistRequest);
 			}
 		}
 		else {
 			// setup to replace the existing value
 			if (!nodeAtOffset.getFirstStructuredDocumentRegion().isEnded() && (documentPosition < sdRegion.getStartOffset(completionRegion))) {
 				// if the IStructuredDocumentRegion isn't closed and the
 				// cursor is in front of the value, add
 				contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, documentPosition, 0, matchString);
 				addAttributeNameProposals(contentAssistRequest);
 			}
 			else {
 				IDOMAttr xpathNode = this.isXPathRegion(nodeAtOffset, completionRegion, documentPosition);
 				if (xpathNode != null) {
 					// This needs to setup the content assistance correctly. Here is what needs to happen:
 					// 1. Adjust the matchString (This should have been calculated earlier)
 					// 2. Get the current tokens offset position..this will be the starting offset.
 					// 3. Get the replacement length...this is the difference between the token offset and the next token or end of the string
 					XPathParser parser = new XPathParser(xpathNode.getValue());
 					int startOffset = xpathNode.getValueRegionStartOffset() + parser.getTokenStartOffset(1, documentPosition - xpathNode.getValueRegionStartOffset()) - 1;
 					int replacementLength = documentPosition - startOffset;
 					contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, startOffset, replacementLength, matchString);
 				} else {
 					contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, sdRegion.getStartOffset(completionRegion), completionRegion.getTextLength(), matchString);
 				}

 				addAttributeValueProposals(contentAssistRequest);
 			}
 		}
 		return contentAssistRequest;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2008 Standards for Technology in Automotive Retail and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* David Carver - STAR - bug 213849 - initial API and implementation
	* David Carver - STAR - bug 230958 - refactored to fix bug with getting
	* the DOM Document for the current editor
	*
	*******************************************************************************/
	package org.eclipse.wst.xsl.ui.internal.contentassist;

	import java.util.ArrayList;
	import java.util.List;

	import javax.xml.transform.TransformerException;

	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.contentassist.ICompletionProposal;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
	import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegion;
	import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegionList;
	import org.eclipse.wst.sse.ui.internal.contentassist.ContentAssistUtils;
	import org.eclipse.wst.sse.ui.internal.contentassist.CustomCompletionProposal;
	import org.eclipse.wst.xml.core.internal.provisional.document.IDOMAttr;
	import org.eclipse.wst.xml.core.internal.provisional.document.IDOMNode;
	import org.eclipse.wst.xml.core.internal.regions.DOMRegionContext;
	import org.eclipse.wst.xml.ui.internal.contentassist.ContentAssistRequest;
	import org.eclipse.wst.xml.ui.internal.contentassist.XMLContentAssistProcessor;
	import org.eclipse.wst.xml.xpath.core.internal.parser.XPathParser;
	import org.eclipse.wst.xml.xpath.core.util.XSLTXPathHelper;
	import org.eclipse.wst.xml.xpath.ui.internal.contentassist.XPathTemplateCompletionProcessor;
	import org.eclipse.wst.xml.xpath.ui.internal.templates.TemplateContextTypeIdsXPath;
	import org.eclipse.wst.xsl.core.XSLCore;
	import org.eclipse.wst.xsl.core.internal.XSLCorePlugin;
	import org.eclipse.wst.xsl.core.internal.util.StructuredDocumentUtil;
	import org.eclipse.wst.xsl.ui.internal.XSLUIPlugin;
	import org.eclipse.wst.xsl.ui.internal.util.XSLPluginImageHelper;
	import org.eclipse.wst.xsl.ui.internal.util.XSLPluginImages;
	import org.w3c.dom.Element;
	import org.w3c.dom.NamedNodeMap;
	import org.w3c.dom.Node;
	import org.w3c.dom.NodeList;

	/**
	* The XSL Content Assist Processor provides content assistance for various
	* attributes values within the XSL Editor. This includes support for xpaths on
	* select statements as well as on test and match attributes.
	*
	* @author David Carver
	*
	*
	*
	*/
	public class XSLContentAssistProcessor extends XMLContentAssistProcessor
	implements IPropertyChangeListener {

	private static final String ATTR_SELECT = "select"; //$NON-NLS-1$
	private static final String ATTR_TEST = "test"; //$NON-NLS-1$
	private static final String ATTR_MATCH = "match"; //$NON-NLS-1$
	/**
	* Retrieve all global variables in the stylesheet.
	*/
	private static final String XPATH_GLOBAL_VARIABLES = "/xsl:stylesheet/xsl:variable"; //$NON-NLS-1$

	/**
	* Retrieve all global parameters in the stylesheet.
	*/
	private static final String XPATH_GLOBAL_PARAMS = "/xsl:stylesheet/xsl:param"; //$NON-NLS-1$

	/**
	* Limit selection of variables to those that are in the local scope.
	*/
	private static final String XPATH_LOCAL_VARIABLES = "ancestor::xsl:template/descendant::xsl:variable"; //$NON-NLS-1$

	/**
	* Limit selection of params to those that are in the local scope.
	*/
	private static final String XPATH_LOCAL_PARAMS = "ancestor::xsl:template/descendant::xsl:param"; //$NON-NLS-1$

	private XPathTemplateCompletionProcessor fTemplateProcessor = null;
	private List<String> fTemplateContexts = new ArrayList<String>();
	private static final byte[] XPATH_LOCK = new byte[0];

	/**
	* The XSL Content Assist Processor handles XSL specific functionality for
	* content assistance. It leverages several XPath selection variables to
	* help with the selection of elements and template names.
	*
	*/
	public XSLContentAssistProcessor() {
	super();
	}



	/**
	* TODO: Add Javadoc
	*
	* @param textViewer
	* @param documentPosition
	* @return
	*
	* @see org.eclipse.wst.xml.ui.contentassist.AbstractContentAssistProcessor#
	* computeCompletionProposals(org.eclipse.jface.text.ITextViewer, int)
	*/
	@Override
	public ICompletionProposal[] computeCompletionProposals(
	ITextViewer textViewer, int documentPosition) {
	fTemplateContexts.clear();
	return super.computeCompletionProposals(textViewer, documentPosition);
	}


	/**
	* Adds Attribute proposals based on the element and the attribute where the
	* content proposal was instantiated.
	*
	* @param contentAssistRequest
	* Content Assist Request that initiated the proposal request
	*
	*/
	@Override
	protected void addAttributeValueProposals(ContentAssistRequest contentAssistRequest) {
	super.addAttributeValueProposals(contentAssistRequest);

	String attributeName = getAttributeName(contentAssistRequest);
	Element rootElement = contentAssistRequest.getNode().getOwnerDocument().getDocumentElement();

	if (attributeName != null) {
	int offset = contentAssistRequest.getReplacementBeginPosition() + 1;

	addAttributeValueOfProposals(contentAssistRequest, contentAssistRequest.getNode().getNamespaceURI(), rootElement, offset);

	if (XSLCore.isXSLNamespace((IDOMNode)contentAssistRequest.getNode())) {
	addSelectAndTestProposals(contentAssistRequest, attributeName, rootElement, offset);
	addMatchProposals(contentAssistRequest, attributeName, offset);
	}
	}
	}

	private void addMatchProposals(ContentAssistRequest contentAssistRequest, String attributeName, int offset) {
	if (attributeName.equals(ATTR_MATCH)) {
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);
	}
	}

	private void addSelectAndTestProposals(
	ContentAssistRequest contentAssistRequest, String attributeName, Element rootElement, int offset) {
	if (attributeName.equals(ATTR_SELECT) \|\| attributeName.equals(ATTR_TEST)) {
	addGlobalProposals(rootElement, contentAssistRequest, offset);
	addLocalProposals(contentAssistRequest.getNode(), contentAssistRequest, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);
	}
	}

	private void addAttributeValueOfProposals(
	ContentAssistRequest contentAssistRequest, String namespace, Element rootElement, int offset) {
	if (contentAssistRequest.getMatchString().contains("{")) {
	addGlobalProposals(rootElement, contentAssistRequest, contentAssistRequest.getReplacementBeginPosition());
	addLocalProposals(contentAssistRequest.getNode(), contentAssistRequest,
	contentAssistRequest.getReplacementBeginPosition());
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.AXIS, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.XPATH, offset);
	addTemplates(contentAssistRequest, TemplateContextTypeIdsXPath.CUSTOM, offset);

	}
	}

	private void addLocalProposals(Node xpathnode,
	ContentAssistRequest contentAssistRequest, int offset) {
	addVariablesProposals(XPATH_LOCAL_VARIABLES, xpathnode,
	contentAssistRequest, offset);
	addVariablesProposals(XPATH_LOCAL_PARAMS, xpathnode,
	contentAssistRequest, offset);
	}

	private void addGlobalProposals(Node xpathnode,
	ContentAssistRequest contentAssistRequest, int offset) {
	addVariablesProposals(XPATH_GLOBAL_VARIABLES, xpathnode,
	contentAssistRequest, offset);
	addVariablesProposals(XPATH_GLOBAL_PARAMS, xpathnode,
	contentAssistRequest, offset);
	}

	/**
	* Adds Parameter and Variables as proposals. This
	* information is selected based on the XPath statement that is sent to it
	* and the input Node passed. It uses a custom composer to XSL Variable
	* proposal.
	*
	* @param xpath
	* @param xpathnode
	* @param contentAssistRequest
	* @param offset
	*/
	private void addVariablesProposals(String xpath, Node xpathnode,
	ContentAssistRequest contentAssistRequest, int offset) {
	synchronized (XPATH_LOCK) {
	try {
	NodeList nodes = XSLTXPathHelper.selectNodeList(xpathnode, xpath);
	int startLength = getCursorPosition() - offset;

	if (hasNodes(nodes)) {
	for (int nodecnt = 0; nodecnt < nodes.getLength(); nodecnt++) {
	Node node = nodes.item(nodecnt);
	String variableName = "$" + node.getAttributes().getNamedItem("name").getNodeValue(); //$NON-NLS-1$ //$NON-NLS-2$

	CustomCompletionProposal proposal = new CustomCompletionProposal(
	variableName, offset, 0, startLength + variableName.length(),
	XSLPluginImageHelper.getInstance().getImage(XSLPluginImages.IMG_VARIABLES),
	variableName, null, null, 0);
	contentAssistRequest.addProposal(proposal);
	}
	}

	} catch (TransformerException ex) {
	XSLUIPlugin.log(ex);
	}
	}
	}

	/**
	* Checks to make sure that the NodeList has data
	* @param nodes A NodeList object
	* @return True if has data, false if empty
	*/
	private boolean hasNodes(NodeList nodes) {
	return nodes != null && nodes.getLength() > 0;
	}

	/**
	* Get the cursor position within the Text Viewer
	* @return An int value containing the cursor position
	*/
	private int getCursorPosition() {
	return fTextViewer.getTextWidget().getCaretOffset();
	}

	/**
	* Adds XPath related templates to the list of proposals
	*
	* @param contentAssistRequest
	* @param context
	* @param startOffset
	*/
	private void addTemplates(ContentAssistRequest contentAssistRequest,
	String context, int startOffset) {
	if (contentAssistRequest == null) {
	return;
	}

	// if already adding template proposals for a certain context type, do
	// not add again
	if (!fTemplateContexts.contains(context)) {
	fTemplateContexts.add(context);
	boolean useProposalList = !contentAssistRequest.shouldSeparate();

	if (getTemplateCompletionProcessor() != null) {
	getTemplateCompletionProcessor().setContextType(context);
	ICompletionProposal[] proposals = getTemplateCompletionProcessor()
	.computeCompletionProposals(fTextViewer, startOffset);
	for (int i = 0; i < proposals.length; ++i) {
	if (useProposalList) {
	contentAssistRequest.addProposal(proposals[i]);
	} else {
	contentAssistRequest.addMacro(proposals[i]);
	}
	}
	}
	}
	}

	private XPathTemplateCompletionProcessor getTemplateCompletionProcessor() {
	if (fTemplateProcessor == null) {
	fTemplateProcessor = new XPathTemplateCompletionProcessor();
	}
	return fTemplateProcessor;
	}

	/**
	* Gets the attribute name that the content assist was triggered on.
	*
	* @param contentAssistRequest
	* @return
	*/
	private String getAttributeName(ContentAssistRequest contentAssistRequest) {
	IStructuredDocumentRegion open = ((IDOMNode)contentAssistRequest.getNode()).getFirstStructuredDocumentRegion();
	ITextRegionList openRegions = open.getRegions();
	int i = openRegions.indexOf(contentAssistRequest.getRegion());
	if (i >= 0) {

	ITextRegion nameRegion = null;
	while (i >= 0) {
	nameRegion = openRegions.get(i--);
	if (nameRegion.getType() == DOMRegionContext.XML_TAG_ATTRIBUTE_NAME) {
	break;
	}
	}

	// String attributeName = nameRegion.getText();
	return open.getText(nameRegion);
	}
	return null;
	}

	/**
	* Get the Match String. This is typically the string-before the current
	* offset position. For a standard XML Region this is calculated from the
	* beginning of the region (i.e. element, attribute, attribute value, etc.
	* For XSL, an additional check has to be made to determine if we are parsing
	* within an XPath region and where we are in the XPath region, as different
	* content assistance can be made available depending on where we are at. This
	* primarily affects TEST, and SELECT attributes.
	* @param parent
	* @param aRegion
	* @param offset
	* @return
	*/
	@Override
	protected String getMatchString(IStructuredDocumentRegion parent, ITextRegion aRegion, int offset) {
	String emptyString = "";

	if (isMatchStringEmpty(parent, aRegion, offset)) {
	return emptyString; //$NON-NLS-1$
	}

	IDOMNode currentNode = (IDOMNode) ContentAssistUtils.getNodeAt(super.fTextViewer, offset);

	IDOMAttr attributeNode = isXPathRegion(currentNode, aRegion, offset);
	if (attributeNode != null) {
	String temp = extractXPathMatchString(attributeNode, aRegion, offset);
	return temp;
	}


	if (hasXMLMatchString(parent, aRegion, offset)) {
	return extractXMLMatchString(parent, aRegion, offset);
	}
	// This is here for saftey reasons.
	return emptyString;
	}

	protected String extractXPathMatchString(IDOMAttr node, ITextRegion aRegion, int offset) {
	if (node.getValue().length() == 0) return "";

	int nodeOffset = node.getValueRegionStartOffset();
	int column = offset - node.getValueRegionStartOffset();
	XPathParser parser = new XPathParser(node.getValue());
	int tokenStart = parser.getTokenStartOffset(1, column);

	if (tokenStart == column) {
	return "";
	}

	return node.getValue().substring(tokenStart - 1, column - 1);
	}

	protected IDOMAttr isXPathRegion(IDOMNode currentNode, ITextRegion aRegion, int offset) {
	if (XSLCore.isXSLNamespace(currentNode)) {
	return getXPathNode(currentNode, aRegion);
	}

	return null;
	}

	protected IDOMAttr getXPathNode(Node node, ITextRegion aRegion) {
	if (node.hasAttributes()) {
	if (hasAttributeAtTextRegion(ATTR_SELECT, node.getAttributes(), aRegion)) {
	return this.getAttributeAtTextRegion(ATTR_SELECT, node.getAttributes(), aRegion);
	}

	if (hasAttributeAtTextRegion(ATTR_TEST, node.getAttributes(), aRegion)) {
	return this.getAttributeAtTextRegion(ATTR_TEST, node.getAttributes(), aRegion);
	}

	}
	return null;
	}

	protected boolean hasAttributeAtTextRegion(String attrName, NamedNodeMap nodeMap, ITextRegion aRegion) {
	IDOMAttr attrNode = (IDOMAttr) nodeMap.getNamedItem(attrName);
	return attrNode != null && attrNode.getValueRegion().getStart() == aRegion.getStart();
	}

	protected IDOMAttr getAttributeAtTextRegion(String attrName, NamedNodeMap nodeMap, ITextRegion aRegion) {
	IDOMAttr node = (IDOMAttr) nodeMap.getNamedItem(attrName);
	if (node != null && node.getValueRegion().getStart() == aRegion.getStart()) {
	return node;
	}
	return null;
	}


	/**
	* An XML Match string is extracted starting from the beginning of the
	* region to the current offset.
	* @param parent
	* @param aRegion
	* @param offset
	* @return
	*/
	protected String extractXMLMatchString(IStructuredDocumentRegion parent,
	ITextRegion aRegion, int offset) {
	return parent.getText(aRegion).substring(0, offset - parent.getStartOffset(aRegion));
	}

	protected boolean hasXMLMatchString(IStructuredDocumentRegion parent,
	ITextRegion aRegion, int offset) {
	return regionHasData(parent, aRegion) && isOffsetAfterStart(parent, aRegion, offset);
	}

	protected boolean isOffsetAfterStart(IStructuredDocumentRegion parent,
	ITextRegion aRegion, int offset) {
	return parent.getStartOffset(aRegion) < offset;
	}

	protected boolean regionHasData(IStructuredDocumentRegion parent,
	ITextRegion aRegion) {
	return parent.getText(aRegion).length() > 0;
	}

	protected boolean isXMLContentRegion(String regionType) {
	return regionType == DOMRegionContext.XML_CONTENT;
	}

	protected boolean isOffsetAfterEndOffset(IStructuredDocumentRegion parent,
	ITextRegion aRegion, int offset) {
	return offset > getRegionEndOffset(parent, aRegion);
	}

	protected int getRegionEndOffset(IStructuredDocumentRegion parent,
	ITextRegion aRegion) {
	return parent.getStartOffset(aRegion) + aRegion.getTextLength();
	}

	protected boolean isXMLTagOpen(String regionType) {
	return regionType == DOMRegionContext.XML_TAG_OPEN;
	}

	protected boolean isAttributeEqualsRegion(String regionType) {
	return regionType == DOMRegionContext.XML_TAG_ATTRIBUTE_EQUALS;
	}

	protected boolean isMatchStringEmpty(IStructuredDocumentRegion parent, ITextRegion aRegion, int offset) {
	return isRegionNull(aRegion) \|\|
	isCloseRegion(aRegion) \|\|
	isAttributeEqualsRegion(aRegion.getType()) \|\|
	isXMLTagOpen(aRegion.getType()) \|\|
	isOffsetAfterEndOffset(parent, aRegion, offset) \|\|
	isXMLContentRegion(aRegion.getType());
	}

	protected boolean isRegionNull(ITextRegion aRegion) {
	return aRegion == null;
	}

	@Override
	protected ContentAssistRequest computeAttributeValueProposals(int documentPosition, String matchString, ITextRegion completionRegion, IDOMNode nodeAtOffset, IDOMNode node) {
	ContentAssistRequest contentAssistRequest = null;
	IStructuredDocumentRegion sdRegion = getStructuredDocumentRegion(documentPosition);
	if ((documentPosition > sdRegion.getStartOffset(completionRegion) + completionRegion.getTextLength()) && (sdRegion.getStartOffset(completionRegion) + completionRegion.getTextLength() != sdRegion.getStartOffset(completionRegion) + completionRegion.getLength())) {
	// setup to add a new attribute at the documentPosition
	IDOMNode actualNode = (IDOMNode) node.getModel().getIndexedRegion(sdRegion.getStartOffset(completionRegion));
	contentAssistRequest = newContentAssistRequest(actualNode, actualNode, sdRegion, completionRegion, documentPosition, 0, matchString);
	addAttributeNameProposals(contentAssistRequest);
	if ((actualNode.getFirstStructuredDocumentRegion() != null) && !actualNode.getFirstStructuredDocumentRegion().isEnded()) {
	addTagCloseProposals(contentAssistRequest);
	}
	}
	else {
	// setup to replace the existing value
	if (!nodeAtOffset.getFirstStructuredDocumentRegion().isEnded() && (documentPosition < sdRegion.getStartOffset(completionRegion))) {
	// if the IStructuredDocumentRegion isn't closed and the
	// cursor is in front of the value, add
	contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, documentPosition, 0, matchString);
	addAttributeNameProposals(contentAssistRequest);
	}
	else {
	IDOMAttr xpathNode = this.isXPathRegion(nodeAtOffset, completionRegion, documentPosition);
	if (xpathNode != null) {
	// This needs to setup the content assistance correctly. Here is what needs to happen:
	// 1. Adjust the matchString (This should have been calculated earlier)
	// 2. Get the current tokens offset position..this will be the starting offset.
	// 3. Get the replacement length...this is the difference between the token offset and the next token or end of the string
	XPathParser parser = new XPathParser(xpathNode.getValue());
	int startOffset = xpathNode.getValueRegionStartOffset() + parser.getTokenStartOffset(1, documentPosition - xpathNode.getValueRegionStartOffset()) - 1;
	int replacementLength = documentPosition - startOffset;
	contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, startOffset, replacementLength, matchString);
	} else {
	contentAssistRequest = newContentAssistRequest(nodeAtOffset, node, sdRegion, completionRegion, sdRegion.getStartOffset(completionRegion), completionRegion.getTextLength(), matchString);
	}

	addAttributeValueProposals(contentAssistRequest);
	}
	}
	return contentAssistRequest;
	}

	}