UrlInterceptRegistry.java revision 9066cfe9886ac131c34d59ed0e2d287b0e3c0087 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.webkit;
18
19import android.webkit.CacheManager.CacheResult;
20import android.webkit.UrlInterceptHandler;
21
22import java.util.Iterator;
23import java.util.LinkedList;
24import java.util.Map;
25
26public final class UrlInterceptRegistry {
27
28    private final static String LOGTAG = "intercept";
29
30    private static boolean mDisabled = false;
31
32    private static LinkedList mHandlerList;
33
34    private static synchronized LinkedList getHandlers() {
35        if(mHandlerList == null)
36            mHandlerList = new LinkedList<UrlInterceptHandler>();
37        return mHandlerList;
38    }
39
40    /**
41     * set the flag to control whether url intercept is enabled or disabled
42     *
43     * @param disabled true to disable the cache
44     */
45    public static synchronized void setUrlInterceptDisabled(boolean disabled) {
46        mDisabled = disabled;
47    }
48
49    /**
50     * get the state of the url intercept, enabled or disabled
51     *
52     * @return return if it is disabled
53     */
54    public static synchronized boolean urlInterceptDisabled() {
55        return mDisabled;
56    }
57
58    /**
59     * Register a new UrlInterceptHandler. This handler will be called
60     * before any that were previously registered.
61     *
62     * @param handler The new UrlInterceptHandler object
63     * @return true if the handler was not previously registered.
64     */
65    public static synchronized boolean registerHandler(
66            UrlInterceptHandler handler) {
67        if (!getHandlers().contains(handler)) {
68            getHandlers().addFirst(handler);
69            return true;
70        } else {
71            return false;
72        }
73    }
74
75    /**
76     * Unregister a previously registered UrlInterceptHandler.
77     *
78     * @param handler A previously registered UrlInterceptHandler.
79     * @return true if the handler was found and removed from the list.
80     */
81    public static synchronized boolean unregisterHandler(
82            UrlInterceptHandler handler) {
83        return getHandlers().remove(handler);
84    }
85
86    /**
87     * Given an url, returns the CacheResult of the first
88     * UrlInterceptHandler interested, or null if none are.
89     *
90     * @return A CacheResult containing surrogate content.
91     */
92    public static synchronized CacheResult getSurrogate(
93            String url, Map<String, String> headers) {
94        if (urlInterceptDisabled())
95            return null;
96        Iterator iter = getHandlers().listIterator();
97        while (iter.hasNext()) {
98            UrlInterceptHandler handler = (UrlInterceptHandler) iter.next();
99            CacheResult result = handler.service(url, headers);
100            if (result != null) {
101                return result;
102            }
103        }
104        return null;
105    }
106}
107