DelegatingConnectionErrorHandler.java revision 645501c2ab19a559ce82a1d5a29ced159a4c30fb 
1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5package org.chromium.mojo.bindings;
6
7import org.chromium.mojo.system.MojoException;
8
9import java.util.Collections;
10import java.util.Set;
11import java.util.WeakHashMap;
12
13/**
14 * A {@link ConnectionErrorHandler} that delegate the errors to a list of registered handlers. This
15 * class will use weak pointers to prevent keeping references to any handlers it delegates to.
16 */
17public class DelegatingConnectionErrorHandler implements ConnectionErrorHandler {
18
19    /**
20     * The registered handlers. This uses a {@link WeakHashMap} so that it doesn't prevent the
21     * handler from being garbage collected.
22     */
23    private final Set<ConnectionErrorHandler> mHandlers =
24            Collections.newSetFromMap(new WeakHashMap<ConnectionErrorHandler, Boolean>());
25
26    /**
27     * @see ConnectionErrorHandler#onConnectionError(MojoException)
28     */
29    @Override
30    public void onConnectionError(MojoException e) {
31        for (ConnectionErrorHandler handler : mHandlers) {
32            handler.onConnectionError(e);
33        }
34    }
35
36    /**
37     * Add a handler that will be notified of any error this object receives.
38     */
39    public void addConnectionErrorHandler(ConnectionErrorHandler handler) {
40        mHandlers.add(handler);
41    }
42
43    /**
44     * Remove a previously registered handler.
45     */
46    public void removeConnectionErrorHandler(ConnectionErrorHandler handler) {
47        mHandlers.remove(handler);
48    }
49}
50