/*******************************************************************************
 * Copyright (c) 2000, 2008 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.text.information.IInformationProvider;

import dwt.dwthelper.utils;

import dwtx.jface.text.IRegion;
import dwtx.jface.text.ITextViewer;


/**
 * Provides information related to the content of a text viewer.
 * <p>
 * In order to provide backward compatibility for clients of <code>IInformationProvider</code>, extension
 * interfaces are used to provide a means of evolution. The following extension interfaces exist:
 * <ul>
 * <li>{@link IInformationProviderExtension} since version 2.1 introducing
 *      the ability to provide the element for a given subject</li>
 * <li>{@link IInformationProviderExtension2} since version 3.0 introducing
 *      the ability to provide its own information control creator</li>
 * </ul>
 * </p>
 * <p>
 * Clients may implement this interface.
 * </p>
 *
 * @see dwtx.jface.text.information.IInformationProviderExtension
 * @see dwtx.jface.text.information.IInformationProviderExtension2
 * @see dwtx.jface.text.information.IInformationPresenter
 * @see dwtx.jface.text.ITextViewer
 * @since 2.0
 */
public interface IInformationProvider {

    /**
     * Returns the region of the text viewer's document close to the given
     * offset that contains a subject about which information can be provided.<p>
     * For example, if information can be provided on a per code block basis,
     * the offset should be used to find the enclosing code block and the source
     * range of the block should be returned.
     *
     * @param textViewer the text viewer in which information has been requested
     * @param offset the offset at which information has been requested
     * @return the region of the text viewer's document containing the information subject
     */
    IRegion getSubject(ITextViewer textViewer, int offset);

    /**
     * Returns the information about the given subject or <code>null</code> if
     * no information is available. It depends on the concrete configuration in which
     * format the information is to be provided. For example, information presented
     * in an information control displaying HTML, should be provided in HTML.
     *
     * @param textViewer the viewer in whose document the subject is contained
     * @param subject the text region constituting the information subject
     * @return the information about the subject
     * @see IInformationPresenter
     * @deprecated As of 2.1, replaced by {@link IInformationProviderExtension#getInformation2(ITextViewer, IRegion)}
     */
    String getInformation(ITextViewer textViewer, IRegion subject);
}