plugins/sqltools/org.eclipse.datatools.sqltools.sqleditor/src/org/eclipse/datatools/sqltools/sqleditor/internal/sql/SQLCompletionProcessor.java

/*******************************************************************************
 * Copyright (c) 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Eclipse Public License 2.0
 * which is available at
 * https://www.eclipse.org/legal/epl-2.0/
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.datatools.sqltools.sqleditor.internal.sql;

import java.util.Arrays;
import java.util.Comparator;

import org.eclipse.datatools.sqltools.editor.contentassist.ISQLDBProposalsService;
import org.eclipse.datatools.sqltools.sqleditor.internal.PreferenceConstants;
import org.eclipse.datatools.sqltools.sqleditor.internal.SQLEditorPlugin;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.jface.text.contentassist.ContextInformation;
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.IContextInformationPresenter;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.swt.graphics.Point;

/**
 * This class implements a content assist processor for SQL code.
 * <p>
 * This processor should be registered with a content assistant in order to get
 * involved in the assisting process.
 * 
 * @author Hetty Dougherty
 *  
 */
public class SQLCompletionProcessor implements IContentAssistProcessor {

    protected IContextInformationValidator fValidator = new SQLValidator();

    private ISQLCompletionEngine fParserCompletionEngine;
	private Comparator fComparator               = new SQLCompletionProposalComparator();
    private ISQLDBProposalsService fDBProposalsService;

    public SQLCompletionProcessor() {
        super();


        fParserCompletionEngine = new SQLParserCompletionEngine();
        fComparator = new SQLCompletionProposalComparator();
        fDBProposalsService = null;
    }

    /**
     * Tells this processor to order the proposals alphabetically.
     * 
     * @param order <code>true</code> if proposals should be ordered.
     */
    public void orderProposalsAlphabetically( boolean order ) {
        fComparator = order ? new SQLCompletionProposalComparator() : null;
    }

    /**
     * Returns a list of proposed content completions based on the specified
     * location within the document that corresponds to the current cursor
     * position within the text-editor control.
     * 
     * @param viewer the viewer whose document is used to compute the proposals
     * @param documentPosition a location within the document
     * @return an array of content-assist proposals
     */
    public ICompletionProposal[] computeCompletionProposals( ITextViewer viewer, int documentOffset ) {
        ICompletionProposal[] result = null;
        
        try {
            IDocument doc = viewer.getDocument();
            ITypedRegion partition = null;

            if (documentOffset > 0) {
                if (doc.getChar( documentOffset - 1 ) == ';')
                    partition = viewer.getDocument().getPartition( documentOffset );
                else
                    // for incomplete statement.
                    partition = viewer.getDocument().getPartition( documentOffset - 1 );
            }
            else
                partition = viewer.getDocument().getPartition( documentOffset );

            Point selection = viewer.getSelectedRange();
            result = fParserCompletionEngine.computeProposals( doc, partition, documentOffset, selection );
            
        }
        catch (BadLocationException x) {
        }
        ;
        
        if (result != null)
            result = order( result );        
        
        return result;
    }

    public IContextInformation[] computeContextInformation(ITextViewer viewer,
	    int documentOffset) {
	IContextInformation[] result = null;

	try {
	    IDocument doc = viewer.getDocument();
	    ITypedRegion partition = null;

	    if (documentOffset > 0) {
		if (doc.getChar(documentOffset - 1) == ';') {
		    partition = viewer.getDocument().getPartition(
			    documentOffset);
		} else {
		    // for incomplete statement.
		    partition = viewer.getDocument().getPartition(
			    documentOffset - 1);
		}
	    } else {
		partition = viewer.getDocument().getPartition(documentOffset);
	    }

	    Point selection = viewer.getSelectedRange();
	    result = fParserCompletionEngine.computeContextInformation(doc,
		    partition, documentOffset, selection);
	} catch (BadLocationException x) {
	}
	return result;
    }

    /**
         * Returns a string of characters which when pressed should
         * automatically display content-assist proposals.
         * 
         * @see IContentAssistProcessor.getCompletionProposalAutoActivationCharacters()
         * 
         * @return string of characters
         */
    public char[] getCompletionProposalAutoActivationCharacters() {
        // activation/trigger to invoke content assist
        IPreferenceStore store = SQLEditorPlugin.getDefault().getPreferenceStore();
        String autoChars = store.getString(PreferenceConstants.AUTO_ACTIVATION_TRIGGER);
        return autoChars.toCharArray() ;
    }

    /**
     * Returns a string of characters which when pressed should automatically
     * display a content-assist tip.
     * 
     * @return string of characters
     */
    public char[] getContextInformationAutoActivationCharacters() {
        return new char[] { '#' };
    }

    /**
     * Returns a delegate used to determine when a displayed tip should be
     * dismissed.
     * 
     * @return a tip closer
     */
    public IContextInformationValidator getContextInformationValidator() {
        return fValidator;
    }

    /**
     * Gets the DBProposalsService.
     * 
     * @return the DBProposalsService
     */
    public ISQLDBProposalsService getDBProposalService() {
        return fDBProposalsService;
    }

    /**
     * Returns the reason why the content-assist processor was unable to produce
     * any proposals or tips.
     * 
     * @return an error message or null if no error occurred
     */
    public String getErrorMessage() {
        return null;
    }

    /**
     * Sets the <code>ISQLDBProposalsService</code> to use to generate DB object
     * proposals (tables, columns) for content assist.
     * 
     * @param dbProposalsService the <code>ISQLDBProposalsService</code> object to use
     */
    public void setDBProposalsService( ISQLDBProposalsService dbProposalsService ) {
        fDBProposalsService = dbProposalsService;
        ((SQLParserCompletionEngine) fParserCompletionEngine).setDBProposalsService( fDBProposalsService );
    }

    /**
     * Orders the given proposals.
     * 
     * @params ICompletionProposal[] List of proposals to be ordered
     */
    private ICompletionProposal[] order( ICompletionProposal[] proposals ) {
        if (fComparator != null)
            Arrays.sort( proposals, fComparator );
        return proposals;
    }

}