content: /*******************************************************************************
   * Copyright (c) 2000, 2011 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.wst.jsdt.internal.ui.text.java;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  import org.eclipse.core.runtime.IProgressMonitor;
  import org.eclipse.jface.dialogs.ErrorDialog;
  import org.eclipse.jface.dialogs.MessageDialog;
  import org.eclipse.jface.text.ITextViewer;
  import org.eclipse.jface.text.contentassist.ICompletionProposal;
  import org.eclipse.jface.text.contentassist.IContextInformation;
  import org.eclipse.jface.text.contentassist.IContextInformationExtension;
  import org.eclipse.swt.graphics.Image;
  import org.eclipse.swt.graphics.Point;
  import org.eclipse.swt.widgets.Shell;
  import org.eclipse.wst.jsdt.core.CompletionProposal;
  import org.eclipse.wst.jsdt.core.IJavaScriptUnit;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.ui.PreferenceConstants;
  import org.eclipse.wst.jsdt.ui.text.java.CompletionProposalCollector;
  import org.eclipse.wst.jsdt.ui.text.java.ContentAssistInvocationContext;
  import org.eclipse.wst.jsdt.ui.text.java.IJavaCompletionProposalComputer;
  import org.eclipse.wst.jsdt.ui.text.java.JavaContentAssistInvocationContext;
  
  /**
   * Computes Java completion proposals and context infos.
   * 
   * 
   */
  public class JavaCompletionProposalComputer implements IJavaCompletionProposalComputer {
  
  	private static final class ContextInformationWrapper implements IContextInformation, IContextInformationExtension {
  
  		private final IContextInformation fContextInformation;
  		private int fPosition;
  
  		public ContextInformationWrapper(IContextInformation contextInformation) {
  			fContextInformation= contextInformation;
  		}
  
  		/*
  		 * @see IContextInformation#getContextDisplayString()
  		 */
  		public String getContextDisplayString() {
  			return fContextInformation.getContextDisplayString();
  		}
  
  			/*
  		 * @see IContextInformation#getImage()
  		 */
  		public Image getImage() {
  			return fContextInformation.getImage();
  		}
  
  		/*
  		 * @see IContextInformation#getInformationDisplayString()
  		 */
  		public String getInformationDisplayString() {
  			return fContextInformation.getInformationDisplayString();
  		}
  
  		/*
  		 * @see IContextInformationExtension#getContextInformationPosition()
  		 */
  		public int getContextInformationPosition() {
  			return fPosition;
  		}
  
  		public void setContextInformationPosition(int position) {
  			fPosition= position;
  		}
  
  		/*
  		 * @see org.eclipse.jface.text.contentassist.IContextInformation#equals(java.lang.Object)
  		 */
  		public boolean equals(Object object) {
  			if (object instanceof ContextInformationWrapper)
  				return fContextInformation.equals(((ContextInformationWrapper) object).fContextInformation);
  			else
  				return fContextInformation.equals(object);
  		}
  	}
  	
  	private String fErrorMessage;
  	
  	public JavaCompletionProposalComputer() {
  	}
  
  	protected int guessContextInformationPosition(ContentAssistInvocationContext context) {
  		return context.getInvocationOffset();
  	}
  
  	private List addContextInformations(JavaContentAssistInvocationContext context, int offset, IProgressMonitor monitor) {
  		List proposals= internalComputeCompletionProposals(offset, context, monitor);
  		List result= new ArrayList(proposals.size());
  
  		for (Iterator it= proposals.iterator(); it.hasNext();) {
  			ICompletionProposal proposal= (ICompletionProposal) it.next();
  			IContextInformation contextInformation= proposal.getContextInformation();
  			if (contextInformation != null) {
  				ContextInformationWrapper wrapper= new ContextInformationWrapper(contextInformation);
  				wrapper.setContextInformationPosition(offset);
  				result.add(wrapper);
  			}
  		}
  		return result;
  	}
  
  	/*
  	 * @see org.eclipse.jface.text.contentassist.ICompletionProposalComputer#computeContextInformation(org.eclipse.jface.text.contentassist.TextContentAssistInvocationContext, org.eclipse.core.runtime.IProgressMonitor)
  	 */
  	public List computeContextInformation(ContentAssistInvocationContext context, IProgressMonitor monitor) {
  		if (context instanceof JavaContentAssistInvocationContext) {
  			JavaContentAssistInvocationContext javaContext= (JavaContentAssistInvocationContext) context;
  			
  			int contextInformationPosition= guessContextInformationPosition(javaContext);
  			List result= addContextInformations(javaContext, contextInformationPosition, monitor);
  			return result;
  		}
  		return Collections.EMPTY_LIST;
  	}
  
  	/*
  	 * @see org.eclipse.jface.text.contentassist.ICompletionProposalComputer#computeCompletionProposals(org.eclipse.jface.text.contentassist.TextContentAssistInvocationContext, org.eclipse.core.runtime.IProgressMonitor)
  	 */
  	public List computeCompletionProposals(ContentAssistInvocationContext context, IProgressMonitor monitor) {
  		if (context instanceof JavaContentAssistInvocationContext) {
  			JavaContentAssistInvocationContext javaContext= (JavaContentAssistInvocationContext) context;
  			return internalComputeCompletionProposals(context.getInvocationOffset(), javaContext, monitor);
  		}
  		return Collections.EMPTY_LIST;
  	}
  
  	private List internalComputeCompletionProposals(int offset, JavaContentAssistInvocationContext context, IProgressMonitor monitor) {
  		IJavaScriptUnit unit= context.getCompilationUnit();
  		if (unit == null)
  			return Collections.EMPTY_LIST;
  		
  		ITextViewer viewer= context.getViewer();
  		
  		CompletionProposalCollector collector= createCollector(context);
  		collector.setInvocationContext(context);
  		
  		// Allow completions for unresolved types - since 3.3
  		collector.setAllowsRequiredProposals(CompletionProposal.FIELD_REF, CompletionProposal.TYPE_REF, true);
  		collector.setAllowsRequiredProposals(CompletionProposal.FIELD_REF, CompletionProposal.TYPE_IMPORT, true);
  		collector.setAllowsRequiredProposals(CompletionProposal.FIELD_REF, CompletionProposal.FIELD_IMPORT, true);
  		
  		collector.setAllowsRequiredProposals(CompletionProposal.METHOD_REF, CompletionProposal.TYPE_REF, true);
  		collector.setAllowsRequiredProposals(CompletionProposal.METHOD_REF, CompletionProposal.TYPE_IMPORT, true);
  		collector.setAllowsRequiredProposals(CompletionProposal.METHOD_REF, CompletionProposal.METHOD_IMPORT, true);
  
  		collector.setAllowsRequiredProposals(CompletionProposal.CONSTRUCTOR_INVOCATION, CompletionProposal.TYPE_REF, true);
  		
  		// Set the favorite list to propose static members - since 3.3 
  		collector.setFavoriteReferences(getFavoriteStaticMembers());
  
  		try {
  			Point selection= viewer.getSelectedRange();
  			if (selection.y > 0)
  				collector.setReplacementLength(selection.y);
  			
  				unit.codeComplete(offset, collector);
  		} catch (JavaScriptModelException x) {
  			Shell shell= viewer.getTextWidget().getShell();
  			if (x.isDoesNotExist() && !unit.getJavaScriptProject().isOnIncludepath(unit))
  				MessageDialog.openInformation(shell, JavaTextMessages.CompletionProcessor_error_notOnBuildPath_title, JavaTextMessages.CompletionProcessor_error_notOnBuildPath_message);
  			else
  				ErrorDialog.openError(shell, JavaTextMessages.CompletionProcessor_error_accessing_title, JavaTextMessages.CompletionProcessor_error_accessing_message, x.getStatus());
  		}
  
  		ICompletionProposal[] javaProposals= collector.getJavaCompletionProposals();
  		int contextInformationOffset= guessContextInformationPosition(context);
  		if (contextInformationOffset != offset) {
  			for (int i= 0; i < javaProposals.length; i++) {
  				if (javaProposals[i] instanceof JavaMethodCompletionProposal) {
  					JavaMethodCompletionProposal jmcp= (JavaMethodCompletionProposal) javaProposals[i];
  					jmcp.setContextInformationPosition(contextInformationOffset);
  				}
  			}
  		}
  		
  		List proposals= new ArrayList(Arrays.asList(javaProposals));
  		if (proposals.size() == 0) {
  			String error= collector.getErrorMessage();
  			if (error.length() > 0)
  				fErrorMessage= error;
  		}
  		return proposals;
  	}
  
  	/**
  	 * Returns the array with favorite static members.
  	 * 
  	 * @return the <code>String</code> array with with favorite static members
  	 * @see org.eclipse.wst.jsdt.core.CompletionRequestor#setFavoriteReferences(String[])
  	 * 
  	 */
  	private String[] getFavoriteStaticMembers() {
  		String serializedFavorites= PreferenceConstants.getPreferenceStore().getString(PreferenceConstants.CODEASSIST_FAVORITE_STATIC_MEMBERS);
  		if (serializedFavorites != null && serializedFavorites.length() > 0)
  			return serializedFavorites.split(";"); //$NON-NLS-1$
  		return new String[0];
  	}
  
  	/**
  	 * Creates the collector used to get proposals from core.
  	 */
  	protected CompletionProposalCollector createCollector(JavaContentAssistInvocationContext context) {
  		CompletionProposalCollector collector = new CompletionProposalCollector(context.getCompilationUnit());
  		collector.setInvocationContext(context);
  		return collector;
  	}
  
  	/*
  	 * @see org.eclipse.jface.text.contentassist.ICompletionProposalComputer#getErrorMessage()
  	 */
  	public String getErrorMessage() {
  		return fErrorMessage;
  	}
  
  	/*
  	 * @see org.eclipse.wst.jsdt.ui.text.java.IJavaCompletionProposalComputer#sessionStarted()
  	 */
  	public void sessionStarted() {
  	}
  
  	/*
  	 * @see org.eclipse.wst.jsdt.ui.text.java.IJavaCompletionProposalComputer#sessionEnded()
  	 */
  	public void sessionEnded() {
  		fErrorMessage= null;
  	}
  }
  