proposal/mutant/src/java/common/org/apache/ant/common/antlib/Converter.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 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.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    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.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.ant.common.antlib;

import org.apache.ant.common.util.ExecutionException;

/**
 * Convert between a string and a data type
 *
 * @author <a href="mailto:conor@apache.org">Conor MacNeill</a>
 * @created 19 January 2002
 */
public interface Converter {
    /**
     * Convert a string from the value given to an instance of the given
     * type.
     *
     * @param value The value to be converted
     * @param type the desired type of the converted object
     * @return the value of the converted object
     * @exception ExecutionException if the conversion cannot be made
     */
    Object convert(String value, Class type) throws ExecutionException;

    /**
     * Initialise the converter. The converter may use the AntContext to
     * request services from the Ant core.
     *
     * @param context the Converter's AntContext
     */
    void init(AntContext context);

    /**
     * Get the list of classes this converter is able to convert to.
     *
     * @return an array of Class objects representing the classes this
     *      converter handles.
     */
    Class[] getTypes();


    /**
     * This method allows a converter to indicate whether it can create 
     * the given type which is a sub-type of one of the converter's main
     * types indicated in getTypes. Most converters can return false here.
     *
     * @param subType the sub-type
     * @return true if this converter can convert a string representation to 
     *              the given subclass of one of its main class
     */
    boolean canConvertSubType(Class subType);
}