/*******************************************************************************
* Copyright (c) 2000, 2006 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.che.jface.text.rules;
/**
* Defines the interface for a rule used in the scanning of text for the purpose of
* document partitioning or text styling. A predicate rule can only return one single
* token after having successfully detected content. This token is called success token.
* Also, it also returns a token indicating that this rule has not been successful.
*
* @see ICharacterScanner
* @since 2.0
*/
public interface IPredicateRule extends IRule {
/**
* Returns the success token of this predicate rule.
*
* @return the success token of this rule
*/
IToken getSuccessToken();
/**
* Evaluates the rule by examining the characters available from
* the provided character scanner. The token returned by this rule
* returns <code>true</code> when calling <code>isUndefined</code>,
* if the text that the rule investigated does not match the rule's requirements. Otherwise,
* this method returns this rule's success token. If this rules relies on a text pattern
* comprising a opening and a closing character sequence this method can also be called
* when the scanner is positioned already between the opening and the closing sequence.
* In this case, <code>resume</code> must be set to <code>true</code>.
*
* @param scanner the character scanner to be used by this rule
* @param resume indicates that the rule starts working between the opening and the closing character sequence
* @return the token computed by the rule
*/
IToken evaluate(ICharacterScanner scanner, boolean resume);
}