Merge "TokenWatcher: fix bug in repeated calls to acquire()." am: dfe472ec am: c214d506

package android.os;

import android.util.Log;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.WeakHashMap;

import java.util.Set;

import android.util.Log;

import java.util.WeakHashMap;

/**

 * Helper class that helps you use IBinder objects as reference counted

 * tokens.  IBinders make good tokens because we find out when they are

 * removed

 * A TokenWatcher watches a collection of {@link IBinder}s. IBinders are added

 * to the collection by calling {@link #acquire}, and removed by calling {@link

 * #release}. IBinders are also implicitly removed when they become weakly

 * reachable. Each IBinder may be added at most once.

 *

 * The {@link #acquired} method is invoked by posting to the specified handler

 * whenever the size of the watched collection becomes nonzero.  The {@link

 * #released} method is invoked on the specified handler whenever the size of

 * the watched collection becomes zero.

 */

public abstract class TokenWatcher

{

     * the current count is 0, the acquired method is called on the given

     * handler.

     *

     * @param token An IBinder object.  If this token has already been acquired,

     *              no action is taken.

     * Note that the same {@code token} can only be acquired once. If this

     * {@code token} has already been acquired, no action is taken. The first

     * subsequent call to {@link #release} will release this {@code token}

     * immediately.

     *

     * @param token An IBinder object.

     * @param tag   A string used by the {@link #dump} method for debugging,

     *              to see who has references.

     */

    public void acquire(IBinder token, String tag)

    {

        synchronized (mTokens) {

            if (mTokens.containsKey(token)) {

                return;

            }

            // explicitly checked to avoid bogus sendNotification calls because

            // of the WeakHashMap and the GC

            int oldSize = mTokens.size();