1 /*
2 * Copyright (c) 2002-2025 Gargoyle Software Inc.
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 * https://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15 package org.htmlunit.javascript;
16
17 import java.lang.ref.WeakReference;
18
19 import org.htmlunit.Page;
20
21 /**
22 * An action triggered by a script execution but that should be executed first when the script is finished.
23 * Example: when a script sets the source of an (i)frame, the request to the specified page will be first
24 * triggered after the script execution.
25 *
26 * @author Marc Guillemot
27 * @author Ronald Brill
28 */
29 public abstract class PostponedAction {
30
31 private final WeakReference<Page> owningPageRef_; // as weak ref in case it may allow page to be GCed
32 private final String description_;
33
34 /**
35 * C'tor.
36 * @param owningPage the page that initiates this action
37 * @param description information making debugging easier
38 */
39 public PostponedAction(final Page owningPage, final String description) {
40 owningPageRef_ = new WeakReference<>(owningPage);
41 description_ = description;
42 }
43
44 /**
45 * Gets the owning page.
46 * @return the page that initiated this action or {@code null} if it has already been GCed
47 */
48 protected Page getOwningPage() {
49 return owningPageRef_.get();
50 }
51
52 /**
53 * Execute the action.
54 * @throws Exception if it fails
55 */
56 public abstract void execute() throws Exception;
57
58 /**
59 * Indicates if the action still needs to be executed.
60 * @return {@code true} if the action needs to be executed
61 */
62 public boolean isStillAlive() {
63 final Page owningPage = getOwningPage();
64 return owningPage != null
65 && owningPage.getEnclosingWindow() != null
66 && owningPage == owningPage.getEnclosingWindow().getEnclosedPage();
67 }
68
69 @Override
70 public String toString() {
71 if (description_ == null) {
72 return super.toString();
73 }
74
75 return "PostponedAction(" + description_ + ")";
76 }
77 }