Java example source code file (LWTextComponentPeer.java)

This example Java source code file (LWTextComponentPeer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, dimension, documentevent, documentlistener, event, fontmetrics, gui, inputmethodevent, inputmethodlistener, inputmethodrequests, insets, lwcomponentpeer, lwtextcomponentpeer, override, platformcomponent, string, swing, text, textevent

The LWTextComponentPeer.java Java example source code

/*
 * Copyright (c) 2011, 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 sun.lwawt;

import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Insets;
import java.awt.SystemColor;
import java.awt.TextComponent;
import java.awt.event.TextEvent;
import java.awt.event.InputMethodListener;
import java.awt.event.InputMethodEvent;
import java.awt.im.InputMethodRequests;
import java.awt.peer.TextComponentPeer;
import sun.awt.AWTAccessor;

import javax.swing.JComponent;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;

/**
 * Lightweight implementation of {@link TextComponentPeer}. Provides useful
 * methods for {@link LWTextAreaPeer} and {@link LWTextFieldPeer}
 */
abstract class LWTextComponentPeer<T extends TextComponent, D extends JComponent>
        extends LWComponentPeer<T, D>
        implements DocumentListener, TextComponentPeer, InputMethodListener {

    private volatile boolean firstChangeSkipped;

    LWTextComponentPeer(final T target,
                        final PlatformComponent platformComponent) {
        super(target, platformComponent);
        if (!getTarget().isBackgroundSet()) {
            getTarget().setBackground(SystemColor.text);
        }
    }

    @Override
    void initializeImpl() {
        super.initializeImpl();
        synchronized (getDelegateLock()) {
            // This listener should be added before setText().
            getTextComponent().getDocument().addDocumentListener(this);
        }
        setEditable(getTarget().isEditable());
        setText(getTarget().getText());
        setCaretPosition(getTarget().getCaretPosition());
        getTarget().addInputMethodListener(this);
        final int start = getTarget().getSelectionStart();
        final int end = getTarget().getSelectionEnd();
        if (end > start) {
            // Should be called after setText() and setCaretPosition()
            select(start, end);
        }
        firstChangeSkipped = true;
    }

    @Override
    protected final void disposeImpl() {
        synchronized (getDelegateLock()) {
            // visible caret has a timer thread which must be stopped
            getTextComponent().getCaret().setVisible(false);
        }
        super.disposeImpl();
    }

    /**
     * This method should be called under getDelegateLock().
     */
    abstract JTextComponent getTextComponent();

    public Dimension getMinimumSize(final int rows, final int columns) {
        final Insets insets;
        synchronized (getDelegateLock()) {
            insets = getTextComponent().getInsets();
        }
        final int borderHeight = insets.top + insets.bottom;
        final int borderWidth = insets.left + insets.right;
        final FontMetrics fm = getFontMetrics(getFont());
        return new Dimension(fm.charWidth(WIDE_CHAR) * columns + borderWidth,
                             fm.getHeight() * rows + borderHeight);
    }

    @Override
    public final void setEditable(final boolean editable) {
        synchronized (getDelegateLock()) {
            getTextComponent().setEditable(editable);
        }
    }

    @Override
    public final String getText() {
        synchronized (getDelegateLock()) {
            return getTextComponent().getText();
        }
    }

    @Override
    public final void setText(final String text) {
        synchronized (getDelegateLock()) {
            // JTextArea.setText() posts two different events (remove & insert).
            // Since we make no differences between text events,
            // the document listener has to be disabled while
            // JTextArea.setText() is called.
            final Document document = getTextComponent().getDocument();
            document.removeDocumentListener(this);
            getTextComponent().setText(text);
            revalidate();
            if (firstChangeSkipped) {
                postEvent(new TextEvent(getTarget(),
                                        TextEvent.TEXT_VALUE_CHANGED));
            }
            document.addDocumentListener(this);
        }
        repaintPeer();
    }

    @Override
    public final int getSelectionStart() {
        synchronized (getDelegateLock()) {
            return getTextComponent().getSelectionStart();
        }
    }

    @Override
    public final int getSelectionEnd() {
        synchronized (getDelegateLock()) {
            return getTextComponent().getSelectionEnd();
        }
    }

    @Override
    public final void select(final int selStart, final int selEnd) {
        synchronized (getDelegateLock()) {
            getTextComponent().select(selStart, selEnd);
        }
        repaintPeer();
    }

    @Override
    public final void setCaretPosition(final int pos) {
        synchronized (getDelegateLock()) {
            getTextComponent().setCaretPosition(pos);
        }
        repaintPeer();
    }

    @Override
    public final int getCaretPosition() {
        synchronized (getDelegateLock()) {
            return getTextComponent().getCaretPosition();
        }
    }

    @Override
    public final InputMethodRequests getInputMethodRequests() {
        synchronized (getDelegateLock()) {
            return getTextComponent().getInputMethodRequests();
        }
    }

    //TODO IN XAWT we just return true..
    @Override
    public final boolean isFocusable() {
        return getTarget().isFocusable();
    }

    protected final void revalidate() {
        synchronized (getDelegateLock()) {
            getTextComponent().invalidate();
            getDelegate().validate();
        }
    }

    protected final void postTextEvent() {
        postEvent(new TextEvent(getTarget(), TextEvent.TEXT_VALUE_CHANGED));
        synchronized (getDelegateLock()) {
            revalidate();
        }
    }

    @Override
    public final void changedUpdate(final DocumentEvent e) {
        postTextEvent();
    }

    @Override
    public final void insertUpdate(final DocumentEvent e) {
        postTextEvent();
    }

    @Override
    public final void removeUpdate(final DocumentEvent e) {
        postTextEvent();
    }

    @Override
    public void inputMethodTextChanged(final InputMethodEvent event) {
        synchronized (getDelegateLock()) {
            AWTAccessor.getComponentAccessor().processEvent(getTextComponent(), event);
        }
    }

    @Override
    public void caretPositionChanged(final InputMethodEvent event) {
        synchronized (getDelegateLock()) {
            AWTAccessor.getComponentAccessor().processEvent(getTextComponent(), event);
        }
    }
}