JavaScriptCompletionProcessor.java

/*******************************************************************************
 * Copyright (c) 2005, 2007 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
 *
 
 *******************************************************************************/
package org.eclipse.dltk.javascript.internal.ui.text.completion;

import org.eclipse.dltk.javascript.core.JavaScriptNature;
import org.eclipse.dltk.ui.text.completion.ScriptCompletionProcessor;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.jface.text.contentassist.ContentAssistant;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.ui.IEditorPart;

/**
 * JavaScript completion processor
 */
public class JavaScriptCompletionProcessor extends ScriptCompletionProcessor {

	public JavaScriptCompletionProcessor(IEditorPart editor,
			ContentAssistant assistant, String partition) {
		super(editor, assistant, partition);
	}

	@Override
	protected String getNatureId() {
		return JavaScriptNature.NATURE_ID;
	}

	@Override
	protected IContextInformationValidator createContextInformationValidator() {
		return new JavaScriptParameterListValidator();
	}

	protected static class JavaScriptParameterListValidator extends
			ScriptParameterListValidator {

		protected int installOffset;
		private IContextInformation info;
		private ITextViewer viewer;

		@Override
		public boolean isContextInformationValid(int offset) {
			if (offset < installOffset)
				return false;
			try {
				String txt = viewer.getDocument().get(installOffset,
						offset - installOffset);
				int counter = 0;
				int inBracket = 0;
				while (counter < txt.length()) {
					char ch = txt.charAt(counter++);
					switch (ch) {
					case '(':
						inBracket++;
						continue;
					case ')':
						inBracket--;
					}
				}
				return inBracket >= 0;
			} catch (BadLocationException e) {
				e.printStackTrace();
			}
			return false;
		}

		@Override
		public void install(IContextInformation info, ITextViewer viewer,
				int offset) {
			this.info = info;
			this.viewer = viewer;
			installOffset = offset;
		}

		@Override
		public boolean updatePresentation(int documentPosition,
				TextPresentation presentation) {
			try {
				if (documentPosition < installOffset)
					return false;
				String text = viewer.getDocument().get(installOffset,
						documentPosition - installOffset);
				int count = 0;
				for (int i = 0; i < text.length(); i++) {
					if (text.charAt(i) == ',')
						count++;
				}
				StyleRange styleRange = presentation.getFirstStyleRange();
				if (styleRange == null) {
					styleRange = new StyleRange();
					styleRange.fontStyle = SWT.BOLD;
					presentation.addStyleRange(styleRange);
				}

				String informationDisplayString = info
						.getInformationDisplayString();
				int index = 0;
				while (count > 0 && index != -1) {
					index = informationDisplayString.indexOf(',', index);
					if (index != -1) {
						count--;
						index++;
					}
				}
				if (index != -1) {
					styleRange.start = index;
					index = informationDisplayString.indexOf(',', index + 1);
					if (index == -1)
						styleRange.length = informationDisplayString.length()
								- styleRange.start;
					else
						styleRange.length = index - styleRange.start;
					return true;
				}

			} catch (BadLocationException e) {
				e.printStackTrace();
			}
			return false;
		}
	}
}