Union.java

/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.io;

/**
 * <p> Equivalent to <code>C/C++ union</code>; this class works in the same
 *     way as {@link Struct} (sub-class) except that all members are mapped
 *     to the same location in memory.</p>
 * <p> Here is an example of C union:
 * [code]
 * union Number {
 *     int   asInt;
 *     float asFloat;
 *     char  asString[12];
 * };[/code]</p>
 * <p> And its Java equivalent:
 * [code]
 * public class Number extends Union {
 *     Signed32   asInt    = new Signed32();
 *     Float32    asFloat  = new Float32();
 *     Utf8String asString = new Utf8String(12);
 * }[/code]</p>
 *  <p> As for any {@link Struct}, fields are directly accessible:
 *  [code]
 *  Number num = new Number();
 *  num.asInt.set(23);
 *  num.asString.set("23"); // Null terminated (C compatible)
 *  float f = num.asFloat.get();[/code]</p>
 * 
 * @author  <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
 * @version 1.0, October 4, 2004
 */
public abstract class Union extends Struct {

    /**
     * Default constructor.
     */
    public Union() {}

    /**
     * Returns <code>true</code>.
     * 
     * @return <code>true</code>
     */
    public final boolean isUnion() {
        return true;
    }
}