/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000 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"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * 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.core.types;

import org.apache.ant.core.execution.*;

/**
 * Helper class for attributes that can only take one of a fixed list
 * of values.
 *
 * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a> 
 */
public abstract class EnumeratedAttribute {

    /** The value of this attribute. */
    private String value;

    /**
     * This is the only method a subclass needs to implement.
     *
     * @return an array holding all possible values of the enumeration.
     */
    public abstract String[] getValues();

    /**
     * Set the value of the enumeration.
     *
     * Invoked by {@link org.apache.ant.core.execution.IntrospectionHelper IntrospectionHelper}.
     *
     * @param value the value of the enumeration
     *
     * @throws ExecutionException if the value is not value
     */
    public final void setValue(String value) throws ExecutionException {
        if (!containsValue(value)) {
            throw new ExecutionException(value + " is not a legal value for this attribute");
        }
        this.value = value;
    }

    /**
     * Is this value included in the enumeration?
     */
    public final boolean containsValue(String value) {
        String[] values = getValues();
        if (values == null || value == null) {
            return false;
        }
        
        for (int i = 0; i < values.length; i++) {
            if (value.equals(values[i])) {
                return true;
            }
        }
        return false;
    }

    /**
     * Retrieves the value.
     */
    public final String getValue() {
        return value;
    }
}