/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.ref.WeakReference;
/**
* Some finalizer tests.
*
* This only works if System.runFinalization() causes finalizers to run
* immediately or very soon.
*/
public class Main {
private static void snooze(int ms) {
try {
Thread.sleep(ms);
} catch (InterruptedException ie) {
System.out.println("Snooze: " + ie.getMessage());
}
}
public static WeakReference makeRef() {
/*
* Make ft in another thread, so there is no danger of
* a conservative reference leaking onto the main thread's
* stack.
*/
final WeakReference[] wimp = new WeakReference[1];
Thread t = new Thread() {
public void run() {
FinalizerTest ft = new FinalizerTest("wahoo");
wimp[0] = new WeakReference(ft);
ft = null;
}
};
t.start();
try {
t.join();
} catch (InterruptedException ie) {
throw new RuntimeException(ie);
}
return wimp[0];
}
public static String wimpString(final WeakReference wimp) {
/*
* Do the work in another thread, so there is no danger of a
* conservative reference to ft leaking onto the main thread's
* stack.
*/
final String[] s = new String[1];
Thread t = new Thread() {
public void run() {
Object ref = wimp.get();
if (ref != null) {
s[0] = ref.toString();
}
}
};
t.start();
try {
t.join();
} catch (InterruptedException ie) {
throw new RuntimeException(ie);
}
return s[0];
}
public static void main(String[] args) {
WeakReference wimp = makeRef();
System.out.println("wimp: " + wimpString(wimp));
/* this will try to collect and finalize ft */
System.out.println("gc");
System.gc();
System.out.println("wimp: " + wimpString(wimp));
System.out.println("finalize");
System.runFinalization();
System.out.println("wimp: " + wimpString(wimp));
System.out.println("sleep");
snooze(1000);
System.out.println("reborn: " + FinalizerTest.mReborn);
System.out.println("wimp: " + wimpString(wimp));
System.out.println("reset reborn");
System.gc();
FinalizerTest.mReborn = FinalizerTest.mNothing;
System.out.println("gc + finalize");
System.gc();
System.runFinalization();
System.out.println("sleep");
snooze(1000);
System.out.println("reborn: " + FinalizerTest.mReborn);
System.out.println("wimp: " + wimpString(wimp));
}
}