java.awt.im
Class InputContext
public
class
InputContext
extends Object
Provides a context for controlling input methods and keyboard layouts.
This class provides the communication layer between the client component,
and the various locale-dependent text entry input methods that can be used
for the client. By default, there is one instance per Window, shared among
all components, but this limits text entry to one component at a time.
Thus, text components can create their own instance to allow text entry
in multiple components at a time.
By using the interfaces of {@link java.awt.im.spi}, you can install
extensions which allow additional input methods. Some of these may use
platform native input methods, or keyboard layouts provided by the platform.
Input methods are unavailable if none have been installed and the platform
has no underlying native input methods. Extensions are installed as jar
files, usually accessed in the default extension location or specified by
the -extdir VM flag. The jar must contain a file named
"META_INF/services/java.awt.im.spi.InputMethodDescriptor" which lists,
one entry per line in UTF-8 encoding, each class in the jar that implements
java.awt.im.spi.InputMethodDescriptor.
Since: 1.2
See Also: getInputContext Component
UNKNOWN: updated to 1.4, but unverified
| Method Summary |
|---|
| void | dispatchEvent(AWTEvent event)
Dispatches an event to the current input method. |
| void | dispose()
Disposes of the input context and release the resources used by it.
|
| void | endComposition()
Ends any input composition that may currently be going on in this
context. |
| Object | getInputMethodControlObject()
Returns a control object from the current input method, or null. |
| static InputContext | getInstance()
Returns a new InputContext.
|
| Locale | getLocale()
Returns the current locale of the current input method or keyboard
layout. |
| boolean | isCompositionEnabled()
Find out if the current input method is enabled.
|
| void | reconvert()
Starts a reconversion operation in the current input method. |
| void | removeNotify(Component client)
Notifies the input context that a client component has been removed from
its containment hierarchy, or that input method support has been disabled
for the component. |
| boolean | selectInputMethod(Locale locale)
Attempts to select an input method or keyboard layout which supports the
given locale. |
| void | setCharacterSubsets(Character.Subset[] subsets)
Sets the subsets of Unicode characters allowed to be input by the current
input method, as well as subsequent input methods. |
| void | setCompositionEnabled(boolean enable)
Changes the enabled status of the current input method. |
protected InputContext()
Construct an InputContext. This is protected, so clients must use
{@link #getInstance()} instead.
public void dispatchEvent(
AWTEvent event)
Dispatches an event to the current input method. This is called
automatically by AWT. If no input method is available, then the event
will never be consumed.
Parameters: event the event to dispatch
Throws: NullPointerException if event is null
public void dispose()
Disposes of the input context and release the resources used by it.
Called automatically by AWT for the default input context of each
Window. If no input methods are available, then this method has no
effect.
public void endComposition()
Ends any input composition that may currently be going on in this
context. Depending on the platform and possibly user preferences, this
may commit or delete uncommitted text. Any changes to the text are
communicated to the active component using an input method event. If no
input methods are available, then this method has no effect. This may
be called for a variety of reasons, such as when the user moves the
insertion point in the client text outside the range of the composed text,
or when text is saved to file.
public
Object getInputMethodControlObject()
Returns a control object from the current input method, or null. A
control object provides implementation-dependent methods that control
the behavior of the input method or obtain information from the input
method. Clients have to compare the result against known input method
control object types. If no input methods are available or the current
input method does not provide an input method control object, then null
is returned.
Returns: the control object, or null
Returns a new InputContext.
Returns: a new instance, initialized to the default locale if available
Returns the current locale of the current input method or keyboard
layout. Returns null if the input context does not have a current input
method or keyboard layout or if the current input method's
{@link InputMethod#getLocale()} method returns null. Not all host
operating systems provide API to determine the locale of the currently
selected native input method or keyboard layout. For host operating
systems that don't provide such API, getLocale assumes that the current
locale of all native input methods or keyboard layouts provided by the
host operating system is the system's default locale.
Returns: the locale of the current input method, or null
Since: 1.3
public boolean isCompositionEnabled()
Find out if the current input method is enabled.
Returns: true if the current input method is enabled
Throws: UnsupportedOperationException if there is no current input method,
or the input method does not support enabling
Since: 1.3
See Also: InputContext
public void reconvert()
Starts a reconversion operation in the current input method. The input
method gets the text to reconvert from the client component, using
{@link InputMethodRequests#getSelectedText(Attribute[])}. Then the
composed and committed text produced by the operation is sent back to
the client using a sequence of InputMethodRequests.
Throws: UnsupportedOperationException if there is no current input method,
or the input method does not support reconversion
Since: 1.3
Notifies the input context that a client component has been removed from
its containment hierarchy, or that input method support has been disabled
for the component. This method is usually called from the client
component's {@link Component#removeNotify()} method. Potentially pending
input from input methods for this component is discarded. If no input
methods are available, then this method has no effect.
Parameters: client the client component
Throws: NullPointerException if client is null
public boolean selectInputMethod(
Locale locale)
Attempts to select an input method or keyboard layout which supports the
given locale. This returns true if a locale is available and was selected.
The following steps are taken in choosing an input method:
- If the currently selected input method or keyboard layout supports
the requested locale, it remains selected.
- If there is no input method or keyboard layout available that
supports the requested locale, the current input method or keyboard
layout remains selected.
- If the user has previously selected an input method or keyboard
layout for the requested locale from the user interface, then the most
recently selected such input method or keyboard layout is reselected.
- Otherwise, an input method or keyboard layout that supports the
requested locale is selected in an implementation dependent way. This
implementation chooses the first input method which supports the requested
locale based on the InputMethodDescriptors loaded from the extensions
installed on the CLASSPATH.
Before switching away from an input method, any currently uncommitted
text is committed. Not all host operating systems provide API to
determine the locale of the currently selected native input method or
keyboard layout, and to select a native input method or keyboard layout
by locale. For host operating systems that don't provide such API,
selectInputMethod assumes that native input methods or keyboard layouts
provided by the host operating system support only the system's default
locale.
An example of where this may be called is in a multi-language document,
when moving the insertion point between sections of different locale, so
that the user may use the input method appropriate to that section of the
document.
Parameters: locale the desired new locale
Returns: true if the new locale is active
Throws: NullPointerException if locale is null
Sets the subsets of Unicode characters allowed to be input by the current
input method, as well as subsequent input methods. The value of null
implies all characters are legal. Applications should not rely on this
behavior, since native host input methods may not allow restrictions.
If no current input method is available, this has no immediate effect.
Parameters: subsets the set of Unicode subsets to accept, or null
public void setCompositionEnabled(boolean enable)
Changes the enabled status of the current input method. An input method
that is enabled for composition interprets incoming events for both
composition and control purposes, while a disabled input method only
interprets control commands (including commands to enable itself).
Parameters: enable whether to enable the input method
Throws: UnsupportedOperationException if there is no current input method,
or the input method does not support enabling
Since: 1.3
See Also: isCompositionEnabled