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Diffstat (limited to 'libjava/classpath/java/awt/im/InputContext.java')
| -rw-r--r-- | libjava/classpath/java/awt/im/InputContext.java | 434 |
1 files changed, 434 insertions, 0 deletions
diff --git a/libjava/classpath/java/awt/im/InputContext.java b/libjava/classpath/java/awt/im/InputContext.java new file mode 100644 index 00000000000..e289677fe9c --- /dev/null +++ b/libjava/classpath/java/awt/im/InputContext.java @@ -0,0 +1,434 @@ +/* InputContext.java -- provides the context for text input + Copyright (C) 2002, 2003, 2004, 2005 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 +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.awt.im; + +import gnu.java.util.EmptyEnumeration; + +import java.awt.AWTEvent; +import java.awt.AWTException; +import java.awt.Component; +import java.awt.im.spi.InputMethod; +import java.awt.im.spi.InputMethodDescriptor; +import java.io.BufferedReader; +import java.io.IOException; +import java.io.InputStreamReader; +import java.net.URL; +import java.util.ArrayList; +import java.util.Enumeration; +import java.util.HashMap; +import java.util.Locale; + +/** + * 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. + * + * <p>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. + * + * @author Eric Blake (ebb9@email.byu.edu) + * @see Component#getInputContext() + * @see Component#enableInputMethods(boolean) + * @since 1.2 + * @status updated to 1.4, but unverified + */ +public class InputContext +{ + /** + * The list of installed input method descriptors. + */ + private static final ArrayList descriptors = new ArrayList(); + static + { + Enumeration e; + try + { + e = ClassLoader.getSystemResources + ("META_INF/services/java.awt.im.spi.InputMethodDescriptor"); + } + catch (IOException ex) + { + // XXX Should we do something else? + e = EmptyEnumeration.getInstance(); + } + while (e.hasMoreElements()) + { + URL url = (URL) e.nextElement(); + BufferedReader in; + String line; + try + { + in = new BufferedReader + (new InputStreamReader(url.openConnection().getInputStream(), + "UTF-8")); + line = in.readLine().trim(); + } + catch (IOException ignored) + { + continue; + } + outer: + while (line != null) + { + try + { + if (line.charAt(0) != '#') + { + Class c = Class.forName(line); + descriptors.add((InputMethodDescriptor) c.newInstance()); + } + line = in.readLine().trim(); + } + catch (IOException ex) + { + continue outer; + } + catch (Exception ignored) + { + } + } + } + } + + /** The current input method; null if no input methods are installed. */ + private InputMethod im; + + /** Map of locales to the most recently selected input method. */ + private final HashMap recent = new HashMap(); + + /** The list of acceptable character subsets. */ + private Character.Subset[] subsets; + + /** + * Construct an InputContext. This is protected, so clients must use + * {@link #getInstance()} instead. + */ + protected InputContext() + { + } + + /** + * Returns a new InputContext. + * + * @return a new instance, initialized to the default locale if available + */ + public static InputContext getInstance() + { + InputContext ic = new InputContext(); + ic.selectInputMethod(Locale.getDefault()); + return ic; + } + + /** + * 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:<ul> + * <li>If the currently selected input method or keyboard layout supports + * the requested locale, it remains selected.</li> + * <li>If there is no input method or keyboard layout available that + * supports the requested locale, the current input method or keyboard + * layout remains selected.</li> + * <li>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.</li> + * <li>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.</li> + * </ul> + * + * <p>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. + * + * <p>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. + * + * @param locale the desired new locale + * @return true if the new locale is active + * @throws NullPointerException if locale is null + */ + public boolean selectInputMethod(Locale locale) + { + if (im != null && im.setLocale(locale)) + { + recent.put(locale, im); + return true; + } + InputMethod next = (InputMethod) recent.get(locale); + outer: + if (next != null) + for (int i = 0, limit = descriptors.size(); i < limit; i++) + { + InputMethodDescriptor d = (InputMethodDescriptor) descriptors.get(i); + Locale[] list; + try + { + list = d.getAvailableLocales(); + } + catch (AWTException ignored) + { + continue; + } + for (int j = list.length; --j >= 0; ) + if (locale.equals(list[j])) + { + try + { + next = d.createInputMethod(); + recent.put(locale, next); + } + catch (Exception ignored) + { + continue; + } + } + } + if (next == null) + return false; + // XXX I'm not sure if this does all the necessary steps in the switch. + if (im != null) + { + try + { + next.setCompositionEnabled(im.isCompositionEnabled()); + } + catch (UnsupportedOperationException ignored) + { + } + im.endComposition(); + im.deactivate(false); + im.hideWindows(); + } + im = next; + im.setLocale(locale); + im.setCharacterSubsets(subsets); + return true; + } + + /** + * 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. + * + * @return the locale of the current input method, or null + * @since 1.3 + */ + public Locale getLocale() + { + return im == null ? null : im.getLocale(); + } + + /** + * 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. + * + * @param subsets the set of Unicode subsets to accept, or null + */ + public void setCharacterSubsets(Character.Subset[] subsets) + { + this.subsets = subsets; + if (im != null) + im.setCharacterSubsets(subsets); + } + + /** + * 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). + * + * @param enable whether to enable the input method + * @throws UnsupportedOperationException if there is no current input method, + * or the input method does not support enabling + * @see #isCompositionEnabled() + * @since 1.3 + */ + public void setCompositionEnabled(boolean enable) + { + if (im == null) + throw new UnsupportedOperationException(); + im.setCompositionEnabled(enable); + } + + /** + * Find out if the current input method is enabled. + * + * @return 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 + * @see #setCompositionEnabled(boolean) + * @since 1.3 + */ + public boolean isCompositionEnabled() + { + if (im == null) + throw new UnsupportedOperationException(); + return im.isCompositionEnabled(); + } + + /** + * Starts a reconversion operation in the current input method. The input + * method gets theh 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 + */ + public void reconvert() + { + if (im == null) + throw new UnsupportedOperationException(); + im.reconvert(); + } + + /** + * 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. + * + * @param event the event to dispatch + * @throws NullPointerException if event is null + */ + public void dispatchEvent(AWTEvent event) + { + if (im != null) + im.dispatchEvent(event); + } + + /** + * 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. + * + * @param client the client component + * @throws NullPointerException if client is null + */ + public void removeNotify(Component client) + { + // XXX What to do with client information? + if (im != null) + { + im.deactivate(false); + im.removeNotify(); + } + } + + /** + * 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 void endComposition() + { + if (im != null) + im.endComposition(); + } + + /** + * 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 dispose() + { + if (im != null) + { + im.deactivate(false); + im.dispose(); + } + } + + /** + * 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. + * + * @return the control object, or null + */ + public Object getInputMethodControlObject() + { + return im == null ? null : im.getControlObject(); + } +} // class InputContext |