/*******************************************************************************
* Copyright (c) 2007, 2009 David Green 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 Green - initial API and implementation
*******************************************************************************/
package org.eclipse.mylyn.internal.wikitext.ui.editor.assist;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.ICompletionProposalExtension4;
import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.mylyn.wikitext.parser.outline.OutlineItem;
import org.eclipse.mylyn.wikitext.parser.outline.OutlineItem.Visitor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
/**
* A content assist implementation that provides proposals for completing document-internal anchor names.
*
* @author David Green
*/
public class AnchorCompletionProcessor implements IContentAssistProcessor {
private static final CompletionProposalComparator PROPOSAL_COMPARATOR = new CompletionProposalComparator();
private static class CompletionProposal implements ICompletionProposal, ICompletionProposalExtension4 {
private final String proposalText;
private final int offset;
private final int replacementLength;
private int relevance;
public CompletionProposal(int offset, String proposalText, int replacementLength) {
this.offset = offset;
this.proposalText = proposalText;
this.replacementLength = replacementLength;
}
public void apply(IDocument document) {
try {
document.replace(offset, replacementLength, proposalText);
} catch (BadLocationException x) {
// ignore
}
}
public String getAdditionalProposalInfo() {
return null;
}
public IContextInformation getContextInformation() {
return null;
}
public String getDisplayString() {
return proposalText;
}
public Image getImage() {
return null;
}
public Point getSelection(IDocument document) {
return new Point(offset + proposalText.length(), 0);
}
public boolean isAutoInsertable() {
return true;
}
public int getRelevance() {
return relevance;
}
public void setRelevance(int relevance) {
this.relevance = relevance;
}
}
private static class CompletionProposalComparator implements Comparator<CompletionProposal> {
public int compare(CompletionProposal o1, CompletionProposal o2) {
if (o1 == o2) {
return 0;
}
if (o1.getRelevance() > o2.getRelevance()) {
return -1;
}
if (o2.getRelevance() > o1.getRelevance()) {
return 1;
}
return o1.proposalText.compareTo(o2.proposalText);
}
}
private OutlineItem outline;
public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {
if (outline == null) {
return null;
}
ITextSelection selection = (ITextSelection) viewer.getSelectionProvider().getSelection();
// adjust offset to end of normalized selection
if (selection.getOffset() == offset) {
offset = selection.getOffset() + selection.getLength();
}
final String prefix = extractPrefix(viewer, offset);
if (prefix == null) {
return null;
}
final List<CompletionProposal> suggestions = new ArrayList<>(20);
final int prefixOffset = offset - prefix.length();
outline.accept(new Visitor() {
public boolean visit(OutlineItem item) {
if (item != outline) {
String id = item.getId();
if (id != null && id.length() > 0) {
suggestions.add(createProposal(prefix, prefixOffset, id));
}
}
return true;
}
});
if (suggestions.isEmpty()) {
return null;
}
Collections.sort(suggestions, PROPOSAL_COMPARATOR);
return suggestions.toArray(new ICompletionProposal[suggestions.size()]);
}
private CompletionProposal createProposal(String prefix, int offset, String id) {
CompletionProposal proposal = new CompletionProposal(offset, id, prefix.length());
if (id.startsWith(prefix)) {
proposal.setRelevance(90);
} else {
proposal.setRelevance(0);
}
return proposal;
}
/**
* get a prefix, but only if it is preceded by a '#' character
*
* @return the prefix (which may be the empty string) that is prefixed by '#', otherwise null
*/
protected String extractPrefix(ITextViewer viewer, int offset) {
int i = offset;
IDocument document = viewer.getDocument();
if (i > document.getLength()) {
return null;
}
try {
while (i > 0) {
char ch = document.getChar(i - 1);
if (!Character.isJavaIdentifierPart(ch)) {
break;
}
i--;
}
if (i == 0 || document.getChar(i - 1) != '#') {
return null;
}
return document.get(i, offset - i);
} catch (BadLocationException e) {
return null;
}
}
public IContextInformation[] computeContextInformation(ITextViewer viewer, int offset) {
return null;
}
public char[] getCompletionProposalAutoActivationCharacters() {
return null;
}
public char[] getContextInformationAutoActivationCharacters() {
return null;
}
public IContextInformationValidator getContextInformationValidator() {
return null;
}
public String getErrorMessage() {
return null;
}
public OutlineItem getOutline() {
return outline;
}
public void setOutline(OutlineItem outline) {
this.outline = outline;
}
}