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Java > Open Source Codes > org > eclipse > jface > text > rules > IPredicateRule


1 /*******************************************************************************
2  * Copyright (c) 2000, 2006 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11
12 package org.eclipse.jface.text.rules;
13
14 /**
15  * Defines the interface for a rule used in the scanning of text for the purpose of
16  * document partitioning or text styling. A predicate rule can only return one single
17  * token after having successfully detected content. This token is called success token.
18  * Also, it also returns a token indicating that this rule has not been successful.
19  *
20  * @see ICharacterScanner
21  * @since 2.0
22  */
23 public interface IPredicateRule extends IRule {
24
25     /**
26      * Returns the success token of this predicate rule.
27      *
28      * @return the success token of this rule
29      */
30     IToken getSuccessToken();
31
32     /**
33      * Evaluates the rule by examining the characters available from
34      * the provided character scanner. The token returned by this rule
35      * returns <code>true</code> when calling <code>isUndefined</code>,
36      * if the text that the rule investigated does not match the rule's requirements. Otherwise,
37      * this method returns this rule's success token. If this rules relies on a text pattern
38      * comprising a opening and a closing character sequence this method can also be called
39      * when the scanner is positioned already between the opening and the closing sequence.
40      * In this case, <code>resume</code> must be set to <code>true</code>.
41      *
42      * @param scanner the character scanner to be used by this rule
43      * @param resume indicates that the rule starts working between the opening and the closing character sequence
44      * @return the token computed by the rule
45      */
46     IToken evaluate(ICharacterScanner scanner, boolean resume);
47 }
48
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