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Java example source code file (JTextComponent.java)
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The JTextComponent.java Java example source code
/*
* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.swing.text;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.beans.Transient;
import java.util.Collections;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Enumeration;
import java.util.Vector;
import java.util.Map;
import java.util.concurrent.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.print.*;
import java.awt.datatransfer.*;
import java.awt.im.InputContext;
import java.awt.im.InputMethodRequests;
import java.awt.font.TextHitInfo;
import java.awt.font.TextAttribute;
import java.awt.print.Printable;
import java.awt.print.PrinterException;
import javax.print.PrintService;
import javax.print.attribute.PrintRequestAttributeSet;
import java.text.*;
import java.text.AttributedCharacterIterator.Attribute;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.*;
import javax.accessibility.*;
import javax.print.attribute.*;
import sun.awt.AppContext;
import sun.swing.PrintingStatus;
import sun.swing.SwingUtilities2;
import sun.swing.text.TextComponentPrintable;
import sun.swing.SwingAccessor;
/**
* <code>JTextComponent is the base class for swing text
* components. It tries to be compatible with the
* <code>java.awt.TextComponent class
* where it can reasonably do so. Also provided are other services
* for additional flexibility (beyond the pluggable UI and bean
* support).
* You can find information on how to use the functionality
* this class provides in
* <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/generaltext.html">General Rules for Using Text Components,
* a section in <em>The Java Tutorial.
*
* <dl>
* <dt>Caret Changes
* <dd>
* The caret is a pluggable object in swing text components.
* Notification of changes to the caret position and the selection
* are sent to implementations of the <code>CaretListener
* interface that have been registered with the text component.
* The UI will install a default caret unless a customized caret
* has been set. <br>
* By default the caret tracks all the document changes
* performed on the Event Dispatching Thread and updates it's position
* accordingly if an insertion occurs before or at the caret position
* or a removal occurs before the caret position. <code>DefaultCaret
* tries to make itself visible which may lead to scrolling
* of a text component within <code>JScrollPane. The default caret
* behavior can be changed by the {@link DefaultCaret#setUpdatePolicy} method.
* <br>
* <b>Note: Non-editable text components also have a caret though
* it may not be painted.
*
* <dt>Commands
* <dd>
* Text components provide a number of commands that can be used
* to manipulate the component. This is essentially the way that
* the component expresses its capabilities. These are expressed
* in terms of the swing <code>Action interface,
* using the <code>TextAction implementation.
* The set of commands supported by the text component can be
* found with the {@link #getActions} method. These actions
* can be bound to key events, fired from buttons, etc.
*
* <dt>Text Input
* <dd>
* The text components support flexible and internationalized text input, using
* keymaps and the input method framework, while maintaining compatibility with
* the AWT listener model.
* <p>
* A {@link javax.swing.text.Keymap} lets an application bind key
* strokes to actions.
* In order to allow keymaps to be shared across multiple text components, they
* can use actions that extend <code>TextAction.
* <code>TextAction can determine which JTextComponent
* most recently has or had focus and therefore is the subject of
* the action (In the case that the <code>ActionEvent
* sent to the action doesn't contain the target text component as its source).
* <p>
* The <a href="../../../../technotes/guides/imf/spec.html">input method framework
* lets text components interact with input methods, separate software
* components that preprocess events to let users enter thousands of
* different characters using keyboards with far fewer keys.
* <code>JTextComponent is an active client of
* the framework, so it implements the preferred user interface for interacting
* with input methods. As a consequence, some key events do not reach the text
* component because they are handled by an input method, and some text input
* reaches the text component as committed text within an {@link
* java.awt.event.InputMethodEvent} instead of as a key event.
* The complete text input is the combination of the characters in
* <code>keyTyped key events and committed text in input method events.
* <p>
* The AWT listener model lets applications attach event listeners to
* components in order to bind events to actions. Swing encourages the
* use of keymaps instead of listeners, but maintains compatibility
* with listeners by giving the listeners a chance to steal an event
* by consuming it.
* <p>
* Keyboard event and input method events are handled in the following stages,
* with each stage capable of consuming the event:
*
* <table border=1 summary="Stages of keyboard and input method event handling">
* <tr>
* <th id="stage">Stage
* <th id="ke">KeyEvent
* <th id="ime">InputMethodEvent |
* <tr>
*
* <p>
* The model is defined by the {@link Document} interface.
* This is intended to provide a flexible text storage mechanism
* that tracks change during edits and can be extended to more sophisticated
* models. The model interfaces are meant to capture the capabilities of
* expression given by SGML, a system used to express a wide variety of
* content.
* Each modification to the document causes notification of the
* details of the change to be sent to all observers in the form of a
* {@link DocumentEvent} which allows the views to stay up to date with the model.
* This event is sent to observers that have implemented the
* {@link DocumentListener}
* interface and registered interest with the model being observed.
*
* <dt>Location Information
* <dd>
* The capability of determining the location of text in
* the view is provided. There are two methods, {@link #modelToView}
* and {@link #viewToModel} for determining this information.
*
* <dt>Undo/Redo support
* <dd>
* Support for an edit history mechanism is provided to allow
* undo/redo operations. The text component does not itself
* provide the history buffer by default, but does provide
* the <code>UndoableEdit records that can be used in conjunction
* with a history buffer to provide the undo/redo support.
* The support is provided by the Document model, which allows
* one to attach UndoableEditListener implementations.
*
* <dt>Thread Safety
* <dd>
* The swing text components provide some support of thread
* safe operations. Because of the high level of configurability
* of the text components, it is possible to circumvent the
* protection provided. The protection primarily comes from
* the model, so the documentation of <code>AbstractDocument
* describes the assumptions of the protection provided.
* The methods that are safe to call asynchronously are marked
* with comments.
*
* <dt>Newlines
* <dd>
* For a discussion on how newlines are handled, see
* <a href="DefaultEditorKit.html">DefaultEditorKit.
*
*
* <dt>Printing support
* <dd>
* Several {@link #print print} methods are provided for basic
* document printing. If more advanced printing is needed, use the
* {@link #getPrintable} method.
* </dl>
*
* <p>
* <strong>Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans™
* has been added to the <code>java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*
* @beaninfo
* attribute: isContainer false
*
* @author Timothy Prinzing
* @author Igor Kushnirskiy (printing support)
* @see Document
* @see DocumentEvent
* @see DocumentListener
* @see Caret
* @see CaretEvent
* @see CaretListener
* @see TextUI
* @see View
* @see ViewFactory
*/
public abstract class JTextComponent extends JComponent implements Scrollable, Accessible
{
/**
* Creates a new <code>JTextComponent.
* Listeners for caret events are established, and the pluggable
* UI installed. The component is marked as editable. No layout manager
* is used, because layout is managed by the view subsystem of text.
* The document model is set to <code>null.
*/
public JTextComponent() {
super();
// enable InputMethodEvent for on-the-spot pre-editing
enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.INPUT_METHOD_EVENT_MASK);
caretEvent = new MutableCaretEvent(this);
addMouseListener(caretEvent);
addFocusListener(caretEvent);
setEditable(true);
setDragEnabled(false);
setLayout(null); // layout is managed by View hierarchy
updateUI();
}
/**
* Fetches the user-interface factory for this text-oriented editor.
*
* @return the factory
*/
public TextUI getUI() { return (TextUI)ui; }
/**
* Sets the user-interface factory for this text-oriented editor.
*
* @param ui the factory
*/
public void setUI(TextUI ui) {
super.setUI(ui);
}
/**
* Reloads the pluggable UI. The key used to fetch the
* new interface is <code>getUIClassID(). The type of
* the UI is <code>TextUI. 
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