/* InputMethod.java -- defines an interface for complex text input
Copyright (C) 2002 Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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package java.awt.im.spi;
import java.awt.AWTEvent;
import java.awt.Rectangle;
import java.util.Locale;
/**
* This interface supports complex text input, often for situations where
* the text is more complex than a keyboard will accomodate. For example,
* this can be used for Chinese, Japanese, and Korean, where multiple
* keystrokes are necessary to compose text. This could also support things
* like phonetic English, or reordering Thai.
*
* <p>These contexts can be loaded by the input method framework, using
* {@link InputContext#selectInputMethod(Locale)}.
*
* @author Eric Blake <ebb9@email.byu.edu>
* @since 1.3
* @status updated to 1.4
*/
public interface InputMethod
{
/**
* Set the input method context, which ties the input method to a client
* component. This is called once automatically when creating the input
* method.
*
* @param context the context for this input method
* @throws NullPointerException if context is null
*/
void setInputMethodContext(InputMethodContext context);
/**
* Sets the input locale. If the input method supports that locale, it
* changes its behavior to be consistent with the locale and returns true.
* Otherwise, it returns false. This is called by
* {@link InputContext#selectInputMethod(Locale)} when the user specifies
* a locale, or when the previously selected input method had a locale.
*
* @param locale the locale to use for input
* @return true if the change is successful
* @throws NullPointerException if locale is null
*/
boolean setLocale(Locale locale);
/**
* Returns the current input locale, or null if none is defined. This is
* called by {@link InputContext#getLocale()}, or before switching input
* methods.
*
* @return the current input locale, or null
*/
Locale getLocale();
/**
* Sets the allowed Unicode subsets that this input method can use. Null
* indicates that all characters are allowed. This is called after creation,
* or when switching to this input method, by
* {@link InputContext#setCharacterSubsets(Character.Subset[])}.
*
* @param subsets the accepted subsets for this input method, or null for all
*/
void setCharacterSubsets(Character.Subset[] subsets);
/**
* Changes the enabled status of this input method. An enabled input method
* accepts incoming events for composition and control purposes, while a
* disabled input method ignores events (except for control purposes). This
* is called by {@link InputContext#setCompositionEnabled(boolean)} or when
* switching from an input method if the previous input method returned
* without exception on {@link #isCompositionEnabled()}.
*
* @param enable whether to enable this input method
* @throws UnsupportedOperationException if enabling/disabling is unsupported
* @see #isCompositionEnabled()
*/
void setCompositionEnabled(boolean enable);
/**
* Find out if this input method is enabled. This is called by
* {@link InputContext#isCompositionEnabled()}, or when switching input
* methods via {@link InputContext#selectInputMethod(Locale)}.
*
* @return true if this input method is enabled
* @throws UnsupportedOperationException if enabling/disabling is unsupported
* @see #setCompositionEnabled(boolean)
*/
boolean isCompositionEnabled();
/**
* Starts a reconversion operation. The input method gets its text from the
* client, 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 InputMethodEvents. This is called
* by {@link InputContext#reconvert()}.
*
* @throws UnsupportedOperationException if reconversion is unsupported
*/
void reconvert();
/**
* Dispatch an event to the input method. If input method support is enabled,
* certain events are dispatched to the input method before the client
* component or event listeners. The input method must either consume the
* event or pass it on to the component. Instances of InputEvent, including
* KeyEvent and MouseEvent, are given to this input method. This method is
* called by {@link InputContext#dispatchEvent(AWTEvent)}.
*
* @param event the event to dispatch
* @throws NullPointerException if event is null
*/
void dispatchEvent(AWTEvent event);
/**
* Notify this input method of changes in the client window. This is called
* when notifications are enabled (see {@link
* InputMethodContext#enableClientWindowNotification(InputMethod, boolean)},
* if {@link #removeNotify(Component)} has not been called. The following
* situations trigger a notification:<ul>
* <li>The client window changes in location, size, visibility,
* iconification, or is closed.</li>
* <li>When enabling client notification (or on the first activation after
* enabling if no client existed at the time).</li>
* <li>When activating a new client after <code>removeNotify</code> was
* called on a previous client.</li>
* </ul>
*
* @param the client window's current bounds, or null
*/
void notifyClientWindowChange(Rectangle bounds);
/**
* Activate this input method for input processing. If the input method
* provides its own windows, it should make them open and visible at this
* time. This method is called when a client component receives a
* FOCUS_GAINED event, or when switching to this input method from another
* one. It is only called when the input method is inactive, assuming that
* new instances begin in an inactive state.
*/
void activate();
/**
* Deactivate this input method, either temporarily or permanently for the
* given client. If the input method provides its own windows, it should
* only close those related to the current composition (such as a lookup
* choice panel), while leaving more persistant windows (like a control
* panel) open to avoid screen flicker. Before control is given to another
* input method, {@link #hideWindows()} will be called on this instance.
* This method is called when a client component receives a
* FOCUS_LOST event, when switching to another input method, or before
* {@link #removeNotify()} when the client is removed.
*
* @param isTemporary true if the focus change is temporary
*/
void deactivate(boolean isTemporary);
/**
* Close or hide all windows opened by this input method. This is called
* before activating a different input method, and before calling
* {@link #dispose()} on this instance. It is only called when the input
* method is inactive.
*/
void hideWindows();
/**
* Notify the input method that a client component has been removed from its
* hierarchy, or that input method support has been disabled. This is
* called by {@link InputContext#removeNotify()}, and only when the input
* method is inactive.
*/
void removeNotify();
/**
* End any input composition currently taking place. Depending on the
* platform and user preferences, this may commit or delete uncommitted text,
* using input method events. 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. This is
* called by {@link InputContext#endComposition()}, when switching to a
* new input method, or by {@link InputContext#selectInputMethod(Locale)}.
*/
void endComposition();
/**
* Disposes the input method and release any resources it is using. In
* particular, the input method should dispose windows and close files. This
* is called by {@link InputContext#dispose()}, when the input method is
* inactive; and nothing will be called on this instance afterwards.
*/
void dispose();
/**
* Returns a control object from this input method, or null. A control object
* provides method to control the behavior of this input method, as well as
* query information about it. The object is implementation dependent, so
* clients must compare the result against known input method control
* object types. This is called by
* {@link InputContext#getInputMethodControlObject()}.
*
* @return the control object, or null
*/
Object getControlObject();
} // interface InputMethod