public final class WebEngine
extends java.lang.Object
WebEngine is a non-visual object capable of managing one Web page
at a time. It loads Web pages, creates their document models, applies
styles as necessary, and runs JavaScript on pages. It provides access
to the document model of the current page, and enables two-way
communication between a Java application and JavaScript code of the page.
The WebEngine class provides two ways to load content into a
WebEngine object:
load(java.lang.String) method. This method uses
the java.net package for network access and protocol handling.
loadContent(java.lang.String, java.lang.String) and
loadContent(java.lang.String) methods.
Loading always happens on a background thread. Methods that initiate
loading return immediately after scheduling a background job. To track
progress and/or cancel a job, use the Worker
instance available from the getLoadWorker() method.
The following example changes the stage title when loading completes successfully:
import javafx.concurrent.Worker.State;
final Stage stage;
webEngine.getLoadWorker().stateProperty().addListener(
new ChangeListener<State>() {
public void changed(ObservableValue ov, State oldState, State newState) {
if (newState == State.SUCCEEDED) {
stage.setTitle(webEngine.getLocation());
}
}
});
webEngine.load("http://javafx.com");
A number of user interface callbacks may be registered with a
WebEngine object. These callbacks are invoked when a script running
on the page requests a user interface operation to be performed, for
example, opens a popup window or changes status text. A WebEngine
object cannot handle such requests internally, so it passes the request to
the corresponding callbacks. If no callback is defined for a specific
operation, the request is silently ignored.
The table below shows JavaScript user interface methods and properties
with their corresponding WebEngine callbacks:
| JavaScript method/property | WebEngine callback |
|---|---|
window.alert() | onAlert
|
window.confirm() | confirmHandler
|
window.open() | createPopupHandler
|
window.open() andwindow.close() | onVisibilityChanged
|
window.prompt() | promptHandler
|
Setting window.status | onStatusChanged
|
Setting any of the following:window.innerWidth, window.innerHeight,window.outerWidth, window.outerHeight,window.screenX, window.screenY,window.screenLeft, window.screenTop
| onResized
|
The following example shows a callback that resizes a browser window:
Stage stage;
webEngine.setOnResized(
new EventHandler<WebEvent<Rectangle2D>>() {
public void handle(WebEvent<Rectangle2D> ev) {
Rectangle2D r = ev.getData();
stage.setWidth(r.getWidth());
stage.setHeight(r.getHeight());
}
});
The WebEngine objects create and manage a Document Object Model
(DOM) for their Web pages. The model can be accessed and modified using
Java DOM Core classes. The getDocument() method provides access
to the root of the model. Additionally DOM Event specification is supported
to define event handlers in Java code.
The following example attaches a Java event listener to an element of a Web page. Clicking on the element causes the application to exit:
EventListener listener = new EventListener() {
public void handleEvent(Event ev) {
Platform.exit();
}
};
Document doc = webEngine.getDocument();
Element el = doc.getElementById("exit-app");
((EventTarget) el).addEventListener("click", listener, false);
It is possible to execute arbitrary JavaScript code in the context of
the current page using the executeScript(java.lang.String) method. For example:
webEngine.executeScript("history.back()");
The execution result is returned to the caller, as described in the next section.
java.lang.Boolean;
and a string becomes a java.lang.String.
A number can be java.lang.Double or a java.lang.Integer,
depending.
The undefined value maps to a specific unique String
object whose value is "undefined".
If the result is a
JavaScript object, it is wrapped as an instance of the
JSObject class.
(As a special case, if the JavaScript object is
a JavaRuntimeObject as discussed in the next section,
then the original Java object is extracted instead.)
The JSObject class is a proxy that provides access to
methods and properties of its underlying JavaScript object.
The most commonly used JSObject methods are
getMember
(to read a named property),
setMember
(to set or define a property),
and call
(to call a function-valued property).
A DOM Node is mapped to an object that both extends
JSObject and implements the appropriate DOM interfaces.
To get a JSObject object for a Node just do a cast:
JSObject jdoc = (JSObject) webEngine.getDocument();
In some cases the context provides a specific Java type that guides
the conversion.
For example if setting a Java String field from a JavaScript
expression, then the JavaScript value is converted to a string.
JSObject methods setMember and
call pass Java objects to the JavaScript environment.
This is roughly the inverse of the JavaScript-to-Java mapping
described above:
Java String, Number, or Boolean objects
are converted to the obvious JavaScript values. A JSObject
object is converted to the original wrapped JavaScript object.
Otherwise a JavaRuntimeObject is created. This is
a JavaScript object that acts as a proxy for the Java object,
in that accessing properties of the JavaRuntimeObject
causes the Java field or method with the same name to be accessed.
Note that the Java objects bound using
JSObject.setMember,
JSObject.setSlot, and
JSObject.call
are implemented using weak references. This means that the Java object
can be garbage collected, causing subsequent accesses to the JavaScript
objects to have no effect.
The JSObject.setMember
method is useful to enable upcalls from JavaScript
into Java code, as illustrated by the following example. The Java code
establishes a new JavaScript object named app. This object has one
public member, the method exit.
public class JavaApplication {
public void exit() {
Platform.exit();
}
}
...
JavaApplication javaApp = new JavaApplication();
JSObject window = (JSObject) webEngine.executeScript("window");
window.setMember("app", javaApp);
You can then refer to the object and the method from your HTML page:
<a href="" onclick="app.exit()">Click here to exit application</a>
When a user clicks the link the application is closed.
Note that in the above example, the application holds a reference
to the JavaApplication instance. This is required for the callback
from JavaScript to execute the desired method.
In the following example, the application does not hold a reference to the Java object:
JSObject window = (JSObject) webEngine.executeScript("window");
window.setMember("app", new JavaApplication());
In this case, since the property value is a local object, "new JavaApplication()",
the value may be garbage collected in next GC cycle.
When a user clicks the link, it does not guarantee to execute the callback method exit.
If there are multiple Java methods with the given name, then the engine selects one matching the number of parameters in the call. (Varargs are not handled.) An unspecified one is chosen if there are multiple ones with the correct number of parameters.
You can pick a specific overloaded method by listing the
parameter types in an extended method name
, which has the
form "method_name(param_type1,...,param_typen)". Typically you'd write the JavaScript expression:
receiver["method_name(param_type1,...,param_typeN)"](arg1,...,argN)
WebEngine objects must be created and accessed solely from the
JavaFX Application thread. This rule also applies to any DOM and JavaScript
objects obtained from the WebEngine object.
| Modifier and Type | Class and Description |
|---|---|
private static class |
WebEngine.AccessorImpl |
private class |
WebEngine.DebuggerImpl
The debugger implementation.
|
private class |
WebEngine.DocumentProperty |
private static class |
WebEngine.InspectorClientImpl
The inspector client implementation.
|
private class |
WebEngine.LoadWorker |
private static class |
WebEngine.PageLoadListener
The page load event listener.
|
(package private) class |
WebEngine.Printable |
private static class |
WebEngine.PulseTimer
Drives the
Timer when Timer.Mode.PLATFORM_TICKS is set. |
private static class |
WebEngine.SelfDisposer |
| Modifier and Type | Field and Description |
|---|---|
private ObjectProperty<Callback<java.lang.String,java.lang.Boolean>> |
confirmHandler |
private ObjectProperty<Callback<PopupFeatures,WebEngine>> |
createPopupHandler |
private WebEngine.DebuggerImpl |
debugger |
private WebEngine.SelfDisposer |
disposer |
private WebEngine.DocumentProperty |
document
The final document.
|
private WebHistory |
history |
private static int |
instanceCount
The number of instances of this class.
|
private BooleanProperty |
javaScriptEnabled
Specifies whether JavaScript execution is enabled.
|
private WebEngine.LoadWorker |
loadWorker
The Worker which shows progress of the web engine as it loads pages.
|
private ReadOnlyStringWrapper |
location
The location of the current page.
|
private static java.util.logging.Logger |
logger |
private ObjectProperty<EventHandler<WebEvent<java.lang.String>>> |
onAlert |
private ObjectProperty<EventHandler<WebErrorEvent>> |
onError
The event handler called when an error occurs.
|
private ObjectProperty<EventHandler<WebEvent<Rectangle2D>>> |
onResized |
private ObjectProperty<EventHandler<WebEvent<java.lang.String>>> |
onStatusChanged |
private ObjectProperty<EventHandler<WebEvent<java.lang.Boolean>>> |
onVisibilityChanged |
private WebPage |
page
The object that provides interaction with the native webkit core.
|
private ObjectProperty<Callback<PromptData,java.lang.String>> |
promptHandler |
private ReadOnlyStringWrapper |
title
The page title.
|
private StringProperty |
userAgent
Specifies user agent ID string.
|
private ObjectProperty<java.io.File> |
userDataDirectory
Specifies the directory to be used by this
WebEngine
to store local user data. |
private boolean |
userDataDirectoryApplied |
private StringProperty |
userStyleSheetLocation
Location of the user stylesheet as a string URL.
|
private ObjectProperty<WebView> |
view
The node associated with this engine.
|
| Modifier | Constructor and Description |
|---|---|
|
WebEngine()
Creates a new engine.
|
|
WebEngine(java.lang.String url)
Creates a new engine and loads a Web page into it.
|
private |
WebEngine(java.lang.String url,
boolean callLoad) |
| Modifier and Type | Method and Description |
|---|---|
private void |
applyUserDataDirectory() |
(package private) static void |
checkThread() |
ObjectProperty<Callback<java.lang.String,java.lang.Boolean>> |
confirmHandlerProperty()
JavaScript
confirm handler property. |
private static void |
createDirectories(java.io.File directory) |
ObjectProperty<Callback<PopupFeatures,WebEngine>> |
createPopupHandlerProperty()
JavaScript popup handler property.
|
private static java.io.File |
defaultUserDataDirectory() |
(package private) void |
dispose() |
ReadOnlyObjectProperty<org.w3c.dom.Document> |
documentProperty()
Document object for the current Web page.
|
java.lang.Object |
executeScript(java.lang.String script)
Executes a script in the context of the current page.
|
private void |
fireError(EventType<WebErrorEvent> eventType,
java.lang.String message,
java.lang.Throwable exception) |
Callback<java.lang.String,java.lang.Boolean> |
getConfirmHandler()
Returns the JavaScript
confirm handler. |
Callback<PopupFeatures,WebEngine> |
getCreatePopupHandler()
Returns the JavaScript popup handler.
|
org.w3c.dom.Document |
getDocument()
Returns the document object for the current Web page.
|
WebHistory |
getHistory()
Returns the session history object.
|
Worker<java.lang.Void> |
getLoadWorker()
Returns a
Worker object that can be used to
track loading progress. |
java.lang.String |
getLocation()
Returns URL of the current Web page.
|
private long |
getMainFrame() |
EventHandler<WebEvent<java.lang.String>> |
getOnAlert()
Returns the JavaScript
alert handler. |
EventHandler<WebErrorEvent> |
getOnError() |
EventHandler<WebEvent<Rectangle2D>> |
getOnResized()
Returns the JavaScript window resize handler.
|
EventHandler<WebEvent<java.lang.String>> |
getOnStatusChanged()
Returns the JavaScript status handler.
|
EventHandler<WebEvent<java.lang.Boolean>> |
getOnVisibilityChanged()
Returns the JavaScript window visibility handler.
|
(package private) WebPage |
getPage() |
Callback<PromptData,java.lang.String> |
getPromptHandler()
Returns the JavaScript
prompt handler. |
java.lang.String |
getTitle()
Returns title of the current Web page.
|
java.lang.String |
getUserAgent() |
java.io.File |
getUserDataDirectory() |
java.lang.String |
getUserStyleSheetLocation() |
Debugger |
impl_getDebugger()
Deprecated.
This is an internal API that can be changed or
removed in the future.
|
boolean |
isJavaScriptEnabled() |
BooleanProperty |
javaScriptEnabledProperty() |
void |
load(java.lang.String url)
Loads a Web page into this engine.
|
void |
loadContent(java.lang.String content)
Loads the given HTML content directly.
|
void |
loadContent(java.lang.String content,
java.lang.String contentType)
Loads the given content directly.
|
ReadOnlyStringProperty |
locationProperty()
URL of the current Web page.
|
ObjectProperty<EventHandler<WebEvent<java.lang.String>>> |
onAlertProperty()
JavaScript
alert handler property. |
ObjectProperty<EventHandler<WebErrorEvent>> |
onErrorProperty() |
ObjectProperty<EventHandler<WebEvent<Rectangle2D>>> |
onResizedProperty()
JavaScript window resize handler property.
|
ObjectProperty<EventHandler<WebEvent<java.lang.String>>> |
onStatusChangedProperty()
JavaScript status handler property.
|
ObjectProperty<EventHandler<WebEvent<java.lang.Boolean>>> |
onVisibilityChangedProperty()
JavaScript window visibility handler property.
|
void |
print(PrinterJob job)
Prints the current Web page using the given printer job.
|
private static boolean |
printStatusOK(PrinterJob job) |
ObjectProperty<Callback<PromptData,java.lang.String>> |
promptHandlerProperty()
JavaScript
prompt handler property. |
private byte[] |
readFully(java.io.BufferedInputStream in) |
void |
reload()
Reloads the current page, whether loaded from URL or directly from a String in
one of the
loadContent methods. |
void |
setConfirmHandler(Callback<java.lang.String,java.lang.Boolean> handler)
Sets the JavaScript
confirm handler. |
void |
setCreatePopupHandler(Callback<PopupFeatures,WebEngine> handler)
Sets the JavaScript popup handler.
|
void |
setJavaScriptEnabled(boolean value) |
void |
setOnAlert(EventHandler<WebEvent<java.lang.String>> handler)
Sets the JavaScript
alert handler. |
void |
setOnError(EventHandler<WebErrorEvent> handler) |
void |
setOnResized(EventHandler<WebEvent<Rectangle2D>> handler)
Sets the JavaScript window resize handler.
|
void |
setOnStatusChanged(EventHandler<WebEvent<java.lang.String>> handler)
Sets the JavaScript status handler.
|
void |
setOnVisibilityChanged(EventHandler<WebEvent<java.lang.Boolean>> handler)
Sets the JavaScript window visibility handler.
|
void |
setPromptHandler(Callback<PromptData,java.lang.String> handler)
Sets the JavaScript
prompt handler. |
void |
setUserAgent(java.lang.String value) |
void |
setUserDataDirectory(java.io.File value) |
void |
setUserStyleSheetLocation(java.lang.String value) |
(package private) void |
setView(WebView view) |
private void |
stop() |
ReadOnlyStringProperty |
titleProperty()
Title of the current Web page.
|
private void |
updateLocation(java.lang.String value) |
private void |
updateTitle() |
StringProperty |
userAgentProperty() |
ObjectProperty<java.io.File> |
userDataDirectoryProperty() |
StringProperty |
userStyleSheetLocationProperty() |
private static final java.util.logging.Logger logger
private static int instanceCount
private final ObjectProperty<WebView> view
private final WebEngine.LoadWorker loadWorker
private final WebPage page
private final WebEngine.SelfDisposer disposer
private final WebEngine.DebuggerImpl debugger
private boolean userDataDirectoryApplied
private final WebEngine.DocumentProperty document
private final ReadOnlyStringWrapper location
private final ReadOnlyStringWrapper title
private BooleanProperty javaScriptEnabled
private StringProperty userStyleSheetLocation
This should be a local URL, i.e. either 'data:',
'file:', or 'jar:'. Remote URLs are not allowed
for security reasons.
private final ObjectProperty<java.io.File> userDataDirectory
WebEngine
to store local user data.
If the value of this property is not null,
the WebEngine will attempt to store local user data
in the respective directory.
If the value of this property is null,
the WebEngine will attempt to store local user data
in an automatically selected system-dependent user- and
application-specific directory.
When a WebEngine is about to start loading a web
page or executing a script for the first time, it checks whether
it can actually use the directory specified by this property.
If the check fails for some reason, the WebEngine invokes
the WebEngine.onError event handler,
if any, with a WebErrorEvent describing the reason.
If the invoked event handler modifies the userDataDirectory
property, the WebEngine retries with the new value as soon
as the handler returns. If the handler does not modify the
userDataDirectory property (which is the default),
the WebEngine continues without local user data.
Once the WebEngine has started loading a web page or
executing a script, changes made to this property have no effect
on where the WebEngine stores or will store local user
data.
Currently, the directory specified by this property is used
only to store the data that backs the window.localStorage
objects. In the future, more types of data can be added.
private StringProperty userAgent
User-Agent HTTP header.private final ObjectProperty<EventHandler<WebEvent<java.lang.String>>> onAlert
private final ObjectProperty<EventHandler<WebEvent<java.lang.String>>> onStatusChanged
private final ObjectProperty<EventHandler<WebEvent<Rectangle2D>>> onResized
private final ObjectProperty<EventHandler<WebEvent<java.lang.Boolean>>> onVisibilityChanged
private final ObjectProperty<Callback<PopupFeatures,WebEngine>> createPopupHandler
private final ObjectProperty<Callback<java.lang.String,java.lang.Boolean>> confirmHandler
private final ObjectProperty<Callback<PromptData,java.lang.String>> promptHandler
private final ObjectProperty<EventHandler<WebErrorEvent>> onError
private final WebHistory history
public WebEngine()
public WebEngine(java.lang.String url)
private WebEngine(java.lang.String url,
boolean callLoad)
public final Worker<java.lang.Void> getLoadWorker()
Worker object that can be used to
track loading progress.public final org.w3c.dom.Document getDocument()
null.public final ReadOnlyObjectProperty<org.w3c.dom.Document> documentProperty()
null
if the Web page failed to load.public final java.lang.String getLocation()
public final ReadOnlyStringProperty locationProperty()
private void updateLocation(java.lang.String value)
public final java.lang.String getTitle()
null.public final ReadOnlyStringProperty titleProperty()
null.private void updateTitle()
public final void setJavaScriptEnabled(boolean value)
public final boolean isJavaScriptEnabled()
public final BooleanProperty javaScriptEnabledProperty()
public final void setUserStyleSheetLocation(java.lang.String value)
public final java.lang.String getUserStyleSheetLocation()
private byte[] readFully(java.io.BufferedInputStream in)
throws java.io.IOException
java.io.IOExceptionpublic final StringProperty userStyleSheetLocationProperty()
public final java.io.File getUserDataDirectory()
public final void setUserDataDirectory(java.io.File value)
public final ObjectProperty<java.io.File> userDataDirectoryProperty()
public final void setUserAgent(java.lang.String value)
public final java.lang.String getUserAgent()
public final StringProperty userAgentProperty()
public final EventHandler<WebEvent<java.lang.String>> getOnAlert()
alert handler.public final void setOnAlert(EventHandler<WebEvent<java.lang.String>> handler)
alert handler.onAlertProperty(),
getOnAlert()public final ObjectProperty<EventHandler<WebEvent<java.lang.String>>> onAlertProperty()
alert handler property. This handler is invoked
when a script running on the Web page calls the alert function.public final EventHandler<WebEvent<java.lang.String>> getOnStatusChanged()
public final void setOnStatusChanged(EventHandler<WebEvent<java.lang.String>> handler)
onStatusChangedProperty(),
getOnStatusChanged()public final ObjectProperty<EventHandler<WebEvent<java.lang.String>>> onStatusChangedProperty()
window.status property.public final EventHandler<WebEvent<Rectangle2D>> getOnResized()
public final void setOnResized(EventHandler<WebEvent<Rectangle2D>> handler)
onResizedProperty(),
getOnResized()public final ObjectProperty<EventHandler<WebEvent<Rectangle2D>>> onResizedProperty()
window object.public final EventHandler<WebEvent<java.lang.Boolean>> getOnVisibilityChanged()
public final void setOnVisibilityChanged(EventHandler<WebEvent<java.lang.Boolean>> handler)
public final ObjectProperty<EventHandler<WebEvent<java.lang.Boolean>>> onVisibilityChangedProperty()
window object.public final Callback<PopupFeatures,WebEngine> getCreatePopupHandler()
public final void setCreatePopupHandler(Callback<PopupFeatures,WebEngine> handler)
public final ObjectProperty<Callback<PopupFeatures,WebEngine>> createPopupHandlerProperty()
To satisfy this request a handler may create a new WebEngine,
attach a visibility handler and optionally a resize handler, and return
the newly created engine. To block the popup, a handler should return
null.
By default, a popup handler is installed that opens popups in this
WebEngine.
PopupFeaturespublic final Callback<java.lang.String,java.lang.Boolean> getConfirmHandler()
confirm handler.public final void setConfirmHandler(Callback<java.lang.String,java.lang.Boolean> handler)
confirm handler.confirmHandlerProperty(),
getConfirmHandler()public final ObjectProperty<Callback<java.lang.String,java.lang.Boolean>> confirmHandlerProperty()
confirm handler property. This handler is invoked
when a script running on the Web page calls the confirm function.
An implementation may display a dialog box with Yes and No options, and return the user's choice.
public final Callback<PromptData,java.lang.String> getPromptHandler()
prompt handler.public final void setPromptHandler(Callback<PromptData,java.lang.String> handler)
prompt handler.promptHandlerProperty(),
getPromptHandler(),
PromptDatapublic final ObjectProperty<Callback<PromptData,java.lang.String>> promptHandlerProperty()
prompt handler property. This handler is invoked
when a script running on the Web page calls the prompt function.
An implementation may display a dialog box with an text field, and return the user's input.
PromptDatapublic final EventHandler<WebErrorEvent> getOnError()
public final void setOnError(EventHandler<WebErrorEvent> handler)
public final ObjectProperty<EventHandler<WebErrorEvent>> onErrorProperty()
public void load(java.lang.String url)
url - URL of the web page to loadpublic void loadContent(java.lang.String content)
load(String), this method is asynchronous.public void loadContent(java.lang.String content,
java.lang.String contentType)
load(String), this method is asynchronous. This method also allows you to
specify the content type of the string being loaded, and so may optionally support
other types besides just HTML.public void reload()
loadContent methods.public WebHistory getHistory()
public java.lang.Object executeScript(java.lang.String script)
java.lang.Integer
java.lang.Double
java.lang.String
java.lang.Boolean
null to null
netscape.javascript.JSObject
netscape.javascript.JSObject, that also implement
org.w3c.dom.Node
JavaRuntimeObject
which is used to wrap a Java object as a JavaScript value - in this
case we just extract the original Java value.
private long getMainFrame()
WebPage getPage()
void setView(WebView view)
private void stop()
private void applyUserDataDirectory()
private static java.io.File defaultUserDataDirectory()
private static void createDirectories(java.io.File directory)
throws java.io.IOException
java.io.IOExceptionprivate void fireError(EventType<WebErrorEvent> eventType, java.lang.String message, java.lang.Throwable exception)
void dispose()
static void checkThread()
@Deprecated public Debugger impl_getDebugger()
All methods of the debugger must be called on the JavaFX Application Thread. The message callback object registered with the debugger is always called on the JavaFX Application Thread.
null.private static final boolean printStatusOK(PrinterJob job)
public void print(PrinterJob job)
This method does not modify the state of the job, nor does it call
PrinterJob.endJob(), so the job may be safely reused afterwards.
job - printer job used for printing