org.eclipse.jface.text/src/org/eclipse/jface/text/templates/TemplateCompletionProcessor.java - platform/eclipse.platform.text - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2015 IBM Corporation 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:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jface.text.templates;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;

 import org.eclipse.swt.graphics.Image;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IRegion;
 import org.eclipse.jface.text.ITextSelection;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.Region;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
 import org.eclipse.jface.text.contentassist.IContextInformation;
 import org.eclipse.jface.text.contentassist.IContextInformationValidator;


 /**
  * A completion processor that computes template proposals. Subclasses need to
  * provide implementations for {@link #getTemplates(String)},
  * {@link #getContextType(ITextViewer, IRegion)} and {@link #getImage(Template)}.
  *
  * @since 3.0
  */
 public abstract class TemplateCompletionProcessor implements IContentAssistProcessor {

 	private static final class ProposalComparator implements Comparator<ICompletionProposal> {
 		@Override
 		public int compare(ICompletionProposal o1, ICompletionProposal o2) {
 			int r1= o1 instanceof TemplateProposal ? ((TemplateProposal) o1).getRelevance() : 0;
 			int r2= o2 instanceof TemplateProposal ? ((TemplateProposal) o2).getRelevance() : 0;
 			return r2 - r1;
 		}
 	}

 	private static final Comparator<ICompletionProposal> fgProposalComparator= new ProposalComparator();

 	@Override
 	public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {

 		ITextSelection selection= (ITextSelection) viewer.getSelectionProvider().getSelection();

 		// adjust offset to end of normalized selection
 		if (selection.getOffset() == offset)
 			offset= selection.getOffset() + selection.getLength();

 		String prefix= extractPrefix(viewer, offset);
 		Region region= new Region(offset - prefix.length(), prefix.length());
 		TemplateContext context= createContext(viewer, region);
 		if (context == null)
 			return new ICompletionProposal[0];

 		context.setVariable("selection", selection.getText()); // name of the selection variables {line, word}_selection //$NON-NLS-1$

 		Template[] templates= getTemplates(context.getContextType().getId());

 		List<ICompletionProposal> matches= new ArrayList<>();
 		for (int i= 0; i < templates.length; i++) {
 			Template template= templates[i];
 			try {
 				context.getContextType().validate(template.getPattern());
 			} catch (TemplateException e) {
 				continue;
 			}
 			if (template.matches(prefix, context.getContextType().getId()))
 				matches.add(createProposal(template, context, (IRegion) region, getRelevance(template, prefix)));
 		}

 		Collections.sort(matches, fgProposalComparator);

 		return matches.toArray(new ICompletionProposal[matches.size()]);
 	}

 	/**
 	 * Creates a new proposal.
 	 * <p>
 	 * Forwards to {@link #createProposal(Template, TemplateContext, IRegion, int)}.
 	 * Do neither call nor override.
 	 * </p>
 	 *
 	 * @param template the template to be applied by the proposal
 	 * @param context the context for the proposal
 	 * @param region the region the proposal applies to
 	 * @param relevance the relevance of the proposal
 	 * @return a new <code>ICompletionProposal</code> for
 	 *         <code>template</code>
 	 * @deprecated use the version specifying <code>IRegion</code> as third parameter
 	 * @since 3.1
 	 */
 	@Deprecated
 	protected ICompletionProposal createProposal(Template template, TemplateContext context, Region region, int relevance) {
 		return createProposal(template, context, (IRegion) region, relevance);
 	}

 	/**
 	 * Creates a new proposal.
 	 * <p>
 	 * The default implementation returns an instance of
 	 * {@link TemplateProposal}. Subclasses may replace this method to provide
 	 * their own implementations.
 	 * </p>
 	 *
 	 * @param template the template to be applied by the proposal
 	 * @param context the context for the proposal
 	 * @param region the region the proposal applies to
 	 * @param relevance the relevance of the proposal
 	 * @return a new <code>ICompletionProposal</code> for
 	 *         <code>template</code>
 	 */
 	protected ICompletionProposal createProposal(Template template, TemplateContext context, IRegion region, int relevance) {
 		return new TemplateProposal(template, context, region, getImage(template), relevance);
 	}

 	/**
 	 * Returns the templates valid for the context type specified by <code>contextTypeId</code>.
 	 *
 	 * @param contextTypeId the context type id
 	 * @return the templates valid for this context type id
 	 */
 	protected abstract Template[] getTemplates(String contextTypeId);

 	/**
 	 * Creates a concrete template context for the given region in the document. This involves finding out which
 	 * context type is valid at the given location, and then creating a context of this type. The default implementation
 	 * returns a <code>DocumentTemplateContext</code> for the context type at the given location.
 	 *
 	 * @param viewer the viewer for which the context is created
 	 * @param region the region into <code>document</code> for which the context is created
 	 * @return a template context that can handle template insertion at the given location, or <code>null</code>
 	 */
 	protected TemplateContext createContext(ITextViewer viewer, IRegion region) {
 		TemplateContextType contextType= getContextType(viewer, region);
 		if (contextType != null) {
 			IDocument document= viewer.getDocument();
 			return new DocumentTemplateContext(contextType, document, region.getOffset(), region.getLength());
 		}
 		return null;
 	}

 	/**
 	 * Returns the context type that can handle template insertion at the given region
 	 * in the viewer's document.
 	 *
 	 * @param viewer the text viewer
 	 * @param region the region into the document displayed by viewer
 	 * @return the context type that can handle template expansion for the given location, or <code>null</code> if none exists
 	 */
 	protected abstract TemplateContextType getContextType(ITextViewer viewer, IRegion region);

 	/**
 	 * Returns the relevance of a template given a prefix. The default
 	 * implementation returns a number greater than zero if the template name
 	 * starts with the prefix, and zero otherwise.
 	 *
 	 * @param template the template to compute the relevance for
 	 * @param prefix the prefix after which content assist was requested
 	 * @return the relevance of <code>template</code>
 	 * @see #extractPrefix(ITextViewer, int)
 	 */
 	protected int getRelevance(Template template, String prefix) {
 		if (template.getName().startsWith(prefix))
 			return 90;
 		return 0;
 	}

 	/**
 	 * Heuristically extracts the prefix used for determining template relevance
 	 * from the viewer's document. The default implementation returns the String from
 	 * offset backwards that forms a java identifier.
 	 *
 	 * @param viewer the viewer
 	 * @param offset offset into document
 	 * @return the prefix to consider
 	 * @see #getRelevance(Template, String)
 	 */
 	protected String extractPrefix(ITextViewer viewer, int offset) {
 		int i= offset;
 		IDocument document= viewer.getDocument();
 		if (i > document.getLength())
 			return ""; //$NON-NLS-1$

 		try {
 			while (i > 0) {
 				char ch= document.getChar(i - 1);
 				if (!Character.isJavaIdentifierPart(ch))
 					break;
 				i--;
 			}

 			return document.get(i, offset - i);
 		} catch (BadLocationException e) {
 			return ""; //$NON-NLS-1$
 		}
 	}

 	/**
 	 * Returns the image to be used for the proposal for <code>template</code>.
 	 *
 	 * @param template the template for which an image should be returned
 	 * @return the image for <code>template</code>
 	 */
 	protected abstract Image getImage(Template template);

 	@Override
 	public IContextInformation[] computeContextInformation(ITextViewer viewer, int documentOffset) {
 		return null;
 	}

 	@Override
 	public char[] getCompletionProposalAutoActivationCharacters() {
 		return null;
 	}

 	@Override
 	public char[] getContextInformationAutoActivationCharacters() {
 		return null;
 	}

 	@Override
 	public String getErrorMessage() {
 		return null;
 	}

 	@Override
 	public IContextInformationValidator getContextInformationValidator() {
 		return null;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2015 IBM Corporation 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:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jface.text.templates;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.List;

	import org.eclipse.swt.graphics.Image;

	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.IRegion;
	import org.eclipse.jface.text.ITextSelection;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.Region;
	import org.eclipse.jface.text.contentassist.ICompletionProposal;
	import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
	import org.eclipse.jface.text.contentassist.IContextInformation;
	import org.eclipse.jface.text.contentassist.IContextInformationValidator;


	/**
	* A completion processor that computes template proposals. Subclasses need to
	* provide implementations for {@link #getTemplates(String)},
	* {@link #getContextType(ITextViewer, IRegion)} and {@link #getImage(Template)}.
	*
	* @since 3.0
	*/
	public abstract class TemplateCompletionProcessor implements IContentAssistProcessor {

	private static final class ProposalComparator implements Comparator<ICompletionProposal> {
	@Override
	public int compare(ICompletionProposal o1, ICompletionProposal o2) {
	int r1= o1 instanceof TemplateProposal ? ((TemplateProposal) o1).getRelevance() : 0;
	int r2= o2 instanceof TemplateProposal ? ((TemplateProposal) o2).getRelevance() : 0;
	return r2 - r1;
	}
	}

	private static final Comparator<ICompletionProposal> fgProposalComparator= new ProposalComparator();

	@Override
	public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {

	ITextSelection selection= (ITextSelection) viewer.getSelectionProvider().getSelection();

	// adjust offset to end of normalized selection
	if (selection.getOffset() == offset)
	offset= selection.getOffset() + selection.getLength();

	String prefix= extractPrefix(viewer, offset);
	Region region= new Region(offset - prefix.length(), prefix.length());
	TemplateContext context= createContext(viewer, region);
	if (context == null)
	return new ICompletionProposal[0];

	context.setVariable("selection", selection.getText()); // name of the selection variables {line, word}_selection //$NON-NLS-1$

	Template[] templates= getTemplates(context.getContextType().getId());

	List<ICompletionProposal> matches= new ArrayList<>();
	for (int i= 0; i < templates.length; i++) {
	Template template= templates[i];
	try {
	context.getContextType().validate(template.getPattern());
	} catch (TemplateException e) {
	continue;
	}
	if (template.matches(prefix, context.getContextType().getId()))
	matches.add(createProposal(template, context, (IRegion) region, getRelevance(template, prefix)));
	}

	Collections.sort(matches, fgProposalComparator);

	return matches.toArray(new ICompletionProposal[matches.size()]);
	}

	/**
	* Creates a new proposal.
	* <p>
	* Forwards to {@link #createProposal(Template, TemplateContext, IRegion, int)}.
	* Do neither call nor override.
	* </p>
	*
	* @param template the template to be applied by the proposal
	* @param context the context for the proposal
	* @param region the region the proposal applies to
	* @param relevance the relevance of the proposal
	* @return a new <code>ICompletionProposal</code> for
	* <code>template</code>
	* @deprecated use the version specifying <code>IRegion</code> as third parameter
	* @since 3.1
	*/
	@Deprecated
	protected ICompletionProposal createProposal(Template template, TemplateContext context, Region region, int relevance) {
	return createProposal(template, context, (IRegion) region, relevance);
	}

	/**
	* Creates a new proposal.
	* <p>
	* The default implementation returns an instance of
	* {@link TemplateProposal}. Subclasses may replace this method to provide
	* their own implementations.
	* </p>
	*
	* @param template the template to be applied by the proposal
	* @param context the context for the proposal
	* @param region the region the proposal applies to
	* @param relevance the relevance of the proposal
	* @return a new <code>ICompletionProposal</code> for
	* <code>template</code>
	*/
	protected ICompletionProposal createProposal(Template template, TemplateContext context, IRegion region, int relevance) {
	return new TemplateProposal(template, context, region, getImage(template), relevance);
	}

	/**
	* Returns the templates valid for the context type specified by <code>contextTypeId</code>.
	*
	* @param contextTypeId the context type id
	* @return the templates valid for this context type id
	*/
	protected abstract Template[] getTemplates(String contextTypeId);

	/**
	* Creates a concrete template context for the given region in the document. This involves finding out which
	* context type is valid at the given location, and then creating a context of this type. The default implementation
	* returns a <code>DocumentTemplateContext</code> for the context type at the given location.
	*
	* @param viewer the viewer for which the context is created
	* @param region the region into <code>document</code> for which the context is created
	* @return a template context that can handle template insertion at the given location, or <code>null</code>
	*/
	protected TemplateContext createContext(ITextViewer viewer, IRegion region) {
	TemplateContextType contextType= getContextType(viewer, region);
	if (contextType != null) {
	IDocument document= viewer.getDocument();
	return new DocumentTemplateContext(contextType, document, region.getOffset(), region.getLength());
	}
	return null;
	}

	/**
	* Returns the context type that can handle template insertion at the given region
	* in the viewer's document.
	*
	* @param viewer the text viewer
	* @param region the region into the document displayed by viewer
	* @return the context type that can handle template expansion for the given location, or <code>null</code> if none exists
	*/
	protected abstract TemplateContextType getContextType(ITextViewer viewer, IRegion region);

	/**
	* Returns the relevance of a template given a prefix. The default
	* implementation returns a number greater than zero if the template name
	* starts with the prefix, and zero otherwise.
	*
	* @param template the template to compute the relevance for
	* @param prefix the prefix after which content assist was requested
	* @return the relevance of <code>template</code>
	* @see #extractPrefix(ITextViewer, int)
	*/
	protected int getRelevance(Template template, String prefix) {
	if (template.getName().startsWith(prefix))
	return 90;
	return 0;
	}

	/**
	* Heuristically extracts the prefix used for determining template relevance
	* from the viewer's document. The default implementation returns the String from
	* offset backwards that forms a java identifier.
	*
	* @param viewer the viewer
	* @param offset offset into document
	* @return the prefix to consider
	* @see #getRelevance(Template, String)
	*/
	protected String extractPrefix(ITextViewer viewer, int offset) {
	int i= offset;
	IDocument document= viewer.getDocument();
	if (i > document.getLength())
	return ""; //$NON-NLS-1$

	try {
	while (i > 0) {
	char ch= document.getChar(i - 1);
	if (!Character.isJavaIdentifierPart(ch))
	break;
	i--;
	}

	return document.get(i, offset - i);
	} catch (BadLocationException e) {
	return ""; //$NON-NLS-1$
	}
	}

	/**
	* Returns the image to be used for the proposal for <code>template</code>.
	*
	* @param template the template for which an image should be returned
	* @return the image for <code>template</code>
	*/
	protected abstract Image getImage(Template template);

	@Override
	public IContextInformation[] computeContextInformation(ITextViewer viewer, int documentOffset) {
	return null;
	}

	@Override
	public char[] getCompletionProposalAutoActivationCharacters() {
	return null;
	}

	@Override
	public char[] getContextInformationAutoActivationCharacters() {
	return null;
	}

	@Override
	public String getErrorMessage() {
	return null;
	}

	@Override
	public IContextInformationValidator getContextInformationValidator() {
	return null;
	}
	}