/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.search.ui;

/**
 * Computes a score that is used by the search dialog
 * to find the best fitting page for a selection when opened.
 * The score has no upper limit but must be at least
 * <code>LOWEST</code>. Higher values means the page is better
 * suited for the given selection input.
 * <p>
 * For example, a Java-specific search page score computer could test
 * if the page is a Java search page and returns high scores
 * for Java elements as selection input.
 *
 * Intended to be implemented.
 * </p>
 */
public interface ISearchPageScoreComputer {

	/**
	 * Invalid score value indicating a score is unknown or undecided.
	 */
	public static final int UNKNOWN= -1;

	/**
	 * Lowest possible valid score.
	 */
	public static final int LOWEST= 0;

	/**
	 * Computes and returns a score indicating how good the page with the given
	 * id can handle the given input element.
	 * The search page id appears as the <code>id</code> attribute of the
	 * <code>&lt;page&gt;</code> element contributed to the
	 * search pages extension point (<code>"org.eclipse.search.searchPages"</code>).
	 *
	 * @param	pageId	the string id of the page for which the score is computed
	 * @param	input		the object based on which the page should open
	 * @return	a score higher or equal to <code>LOWEST</code>, or
	 *		<code>UNKNOWN</code> if this computer cannot decide
	 */
	public int computeScore(String pageId, Object input);
}
