src/main/org/apache/tools/ant/types/selectors/modifiedselector/Algorithm.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
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 *    the documentation and/or other materials provided with the
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 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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 * 4. The names "Ant" and "Apache Software
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
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 */

package org.apache.tools.ant.types.selectors.modifiedselector;


import java.io.File;


/**
 * The <i>Algorithm</i> defines how a value for a file is computed.
 * It must be sure that multiple calls for the same file results in the
 * same value.
 * The implementing class should implement a useful toString() method.
 *
 * @author Jan Mat\u00e8rne
 * @version 2003-09-13
 * @since  Ant 1.6
 */
public interface Algorithm {

    /**
     * Checks its prerequisites.
     * @return <i>true</i> if all is ok, otherwise <i>false</i>.
     */
    boolean isValid();

    /**
     * Get the value for a file.
     * @param file    File object for which the value should be evaluated.
     * @return        The value for that file
     */
    String getValue(File file);
}