IContextInformationValidator.java

/*******************************************************************************
 * Copyright (c) 2000, 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 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.jface.text.contentassist;

import org.eclipse.jface.text.ITextViewer;


/**
 * A context information validator is used to determine if
 * a displayed context information is still valid or should
 * be dismissed.
 * <p>
 * The interface can be implemented by clients.
 * </p>
 *
 * @see IContextInformationPresenter
 */
public interface IContextInformationValidator {

	/**
	 * Installs this validator for the given context information.
	 *
	 * @param info the context information which this validator should check
	 * @param viewer the text viewer on which the information is presented
	 * @param offset the document offset for which the information has been computed
	 */
	void install(IContextInformation info, ITextViewer viewer, int offset);

	/**
	 * Returns whether the information this validator is installed on is still valid
	 * at the given document position.
	 *
	 * @param offset the current offset within the document
	 * @return <code>true</code> if the information also valid at the given document position
	 */
	boolean isContextInformationValid(int offset);
}