/* * Janino - An embedded Java[TM] compiler * * Copyright (c) 2001-2010, Arno Unkrig * 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 name of the author may not be used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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. */ package org.codehaus.janino.util.enumerator; import java.util.Collections; import java.util.HashMap; import java.util.Map; /** * A class that represents an enumerated value. Its main features are its {@link #toString()} and * {@link #fromString(String, Class)} method, which map names to values and vice versa. *
* To use this class, derive from it and define one or more
* public static final
fields, as follows:
*
* public final class Suit extends Enumerator { * * // Exactly N instances of "Suit" exist to represent the N possible values. * public static final Suit CLUBS = new Suit("clubs"); * public static final Suit DIAMONDS = new Suit("diamonds"); * public static final Suit HEARTS = new Suit("hearts"); * public static final Suit SPADES = new Suit("spades"); * * // Optional, if you want to use EumeratorSet arithmetics. * public static final EnumeratorSet NONE = new EnumeratorSet(Suit.class ).setName("none"); * public static final EnumeratorSet ALL = new EnumeratorSet(Suit.class, true).setName("all"); * * // These MUST be declared exactly like this: * private Suit(String name) { super(name); } * public static Suit fromString(String name) throws EnumeratorFormatException { * return (Suit) Enumerator.fromString(name, Suit.class); * } * } ** * @see Effective Java, Item 21 */ @SuppressWarnings({ "rawtypes", "unchecked" }) public abstract class Enumerator { private final String name; private static final Map
* The given string is converted into a value by looking at all instances of the given type * created so far. *
* Derived classes should invoke this method as follows:
* public class Suit extends Enumerator { * ... * public static Suit fromString(String name) throws EnumeratorFormatException { * return (Suit) Enumerator.fromString(name, Suit.class); * } * }* * @throws EnumeratorFormatException if the string cannot be identified */ protected static final Enumerator fromString(String name, Class enumeratorClass) throws EnumeratorFormatException { Enumerator value = (Enumerator) Enumerator.getInstances(enumeratorClass).get(name); if (value == null) throw new EnumeratorFormatException(name); return value; } /** Returns the
name
passed to {@link #Enumerator(String)}. */
@Override public String
toString() { return this.name; }
}