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Java example source code file (BigBinarySearch.java)
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The BigBinarySearch.java Java example source code
/*
* Copyright (c) 2006, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 5045582
* @summary binarySearch of Collections larger than 1<<30
* @author Martin Buchholz
*/
import java.util.*;
public class BigBinarySearch {
// Allows creation of very "big" collections without using too
// many real resources
static class SparseIntegerList
extends AbstractList<Integer>
implements RandomAccess
{
private Map<Integer,Integer> m = new HashMap();
public Integer get(int i) {
if (i < 0) throw new IndexOutOfBoundsException(""+i);
Integer v = m.get(i);
return (v == null) ? Integer.valueOf(0) : v;
}
public int size() {
return Collections.max(m.keySet()) + 1;
}
public Integer set(int i, Integer v) {
if (i < 0) throw new IndexOutOfBoundsException(""+i);
Integer ret = get(i);
if (v == 0)
m.remove(i);
else
m.put(i, v);
return ret;
}
}
/** Check that binarySearch finds an element where we got it */
private static void checkBinarySearch(List<Integer> l, int i) {
try { equal(i, Collections.binarySearch(l, l.get(i))); }
catch (Throwable t) { unexpected(t); }
}
/** Check that binarySearch finds an element where we got it */
private static void checkBinarySearch(List<Integer> l, int i,
Comparator<Integer> comparator) {
try { equal(i, Collections.binarySearch(l, l.get(i), comparator)); }
catch (Throwable t) { unexpected(t); }
}
private static void realMain(String[] args) throws Throwable {
final int n = (1<<30) + 47;
System.out.println("binarySearch(List<Integer>, Integer)");
List<Integer> big = new SparseIntegerList();
big.set( 0, -44);
big.set( 1, -43);
big.set(n-2, 43);
big.set(n-1, 44);
int[] ints = { 0, 1, n-2, n-1 };
Comparator<Integer> reverse = Collections.reverseOrder();
Comparator<Integer> natural = Collections.reverseOrder(reverse);
for (int i : ints) {
checkBinarySearch(big, i);
checkBinarySearch(big, i, null);
checkBinarySearch(big, i, natural);
}
for (int i : ints)
big.set(i, - big.get(i));
for (int i : ints)
checkBinarySearch(big, i, reverse);
}
//--------------------- Infrastructure ---------------------------
static volatile int passed = 0, failed = 0;
static void pass() {passed++;}
static void fail() {failed++; Thread.dumpStack();}
static void fail(String msg) {System.out.println(msg); fail();}
static void unexpected(Throwable t) {failed++; t.printStackTrace();}
static void check(boolean cond) {if (cond) pass(); else fail();}
static void equal(Object x, Object y) {
if (x == null ? y == null : x.equals(y)) pass();
else fail(x + " not equal to " + y);}
public static void main(String[] args) throws Throwable {
try {realMain(args);} catch (Throwable t) {unexpected(t);}
System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
if (failed > 0) throw new AssertionError("Some tests failed");}
}
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