foreach.java

是一款用JAVA 编写的编译器 具有很强的编译功能

/*
 * Copyright 2003 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

/*
 * @test
 * @bug 4855355
 * @summary implement "foreach" loops as specified in JSR 201
 * @author gafter
 *
 * @compile -source 1.5 Foreach.java
 * @run main Foreach
 */

import java.util.Iterator;

public class Foreach implements Iterable<Integer> {

    public Iterator<Integer> iterator() {
	return new Iterator<Integer>() {
	    int next = 1;
	    public boolean hasNext() {
		return next <= (1 << 12);
	    }
	    public void remove() {
		throw new UnsupportedOperationException();
	    }
	    public Integer next() {
		try {
		    return new Integer(next);
		} finally {
		    next <<= 1;
		}
	    }
	};
    }

    public static void main(String[] args) {
	int sum;

	sum = 0;
	int[] a = new int[12];
	for (int i=0; i<12; i++) a[i] = 1<<i;
	for (int i : a) {
	    if (i > 400) break;
	    if (i == 16) continue;
	    sum += i;
	}
	if (sum != 495)
	    throw new AssertionError("cogito ergo " + sum);

	sum = 0;
	Iterable<Integer> x = new Foreach();
	for (Integer j : x)
	    sum += j.intValue();
	if (sum != 8191)
	    throw new AssertionError("cogito ergo " + sum);

	System.out.println("success!");
    }
}