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	/*
	* Copyright (c) 1995, 2014, 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 java.awt;

	import java.awt.peer.LabelPeer;
	import java.io.IOException;
	import java.io.ObjectInputStream;
	import javax.accessibility.*;

	/**
	* A <code>Label</code> object is a component for placing text in a
	* container. A label displays a single line of read-only text.
	* The text can be changed by the application, but a user cannot edit it
	* directly.
	* <p>
	* For example, the code . . .
	*
	* <hr><blockquote><pre>
	* setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
	* add(new Label("Hi There!"));
	* add(new Label("Another Label"));
	* </pre></blockquote><hr>
	* <p>
	* produces the following labels:
	* <p>
	* <img src="doc-files/Label-1.gif" alt="Two labels: 'Hi There!' and 'Another label'"
	* style="float:center; margin: 7px 10px;">
	*
	* @author Sami Shaio
	* @since JDK1.0
	*/
	public class Label extends Component implements Accessible {

	static {
	/* ensure that the necessary native libraries are loaded */
	Toolkit.loadLibraries();
	if (!GraphicsEnvironment.isHeadless()) {
	initIDs();
	}
	}

	/**
	* Indicates that the label should be left justified.
	*/
	public static final int LEFT = 0;

	/**
	* Indicates that the label should be centered.
	*/
	public static final int CENTER = 1;

	/**
	* Indicates that the label should be right justified.
	* @since JDK1.0t.
	*/
	public static final int RIGHT = 2;

	/**
	* The text of this label.
	* This text can be modified by the program
	* but never by the user.
	*
	* @serial
	* @see #getText()
	* @see #setText(String)
	*/
	String text;

	/**
	* The label's alignment. The default alignment is set
	* to be left justified.
	*
	* @serial
	* @see #getAlignment()
	* @see #setAlignment(int)
	*/
	int alignment = LEFT;

	private static final String base = "label";
	private static int nameCounter = 0;

	/*
	* JDK 1.1 serialVersionUID
	*/
	private static final long serialVersionUID = 3094126758329070636L;

	/**
	* Constructs an empty label.
	* The text of the label is the empty string <code>""</code>.
	* @exception HeadlessException if GraphicsEnvironment.isHeadless()
	* returns true.
	* @see java.awt.GraphicsEnvironment#isHeadless
	*/
	public Label() throws HeadlessException {
	this("", LEFT);
	}

	/**
	* Constructs a new label with the specified string of text,
	* left justified.
	* @param text the string that the label presents.
	* A <code>null</code> value
	* will be accepted without causing a NullPointerException
	* to be thrown.
	* @exception HeadlessException if GraphicsEnvironment.isHeadless()
	* returns true.
	* @see java.awt.GraphicsEnvironment#isHeadless
	*/
	public Label(String text) throws HeadlessException {
	this(text, LEFT);
	}

	/**
	* Constructs a new label that presents the specified string of
	* text with the specified alignment.
	* Possible values for <code>alignment</code> are <code>Label.LEFT</code>,
	* <code>Label.RIGHT</code>, and <code>Label.CENTER</code>.
	* @param text the string that the label presents.
	* A <code>null</code> value
	* will be accepted without causing a NullPointerException
	* to be thrown.
	* @param alignment the alignment value.
	* @exception HeadlessException if GraphicsEnvironment.isHeadless()
	* returns true.
	* @see java.awt.GraphicsEnvironment#isHeadless
	*/
	public Label(String text, int alignment) throws HeadlessException {
	GraphicsEnvironment.checkHeadless();
	this.text = text;
	setAlignment(alignment);
	}

	/**
	* Read a label from an object input stream.
	* @exception HeadlessException if
	* <code>GraphicsEnvironment.isHeadless()</code> returns
	* <code>true</code>
	* @serial
	* @since 1.4
	* @see java.awt.GraphicsEnvironment#isHeadless
	*/
	private void readObject(ObjectInputStream s)
	throws ClassNotFoundException, IOException, HeadlessException {
	GraphicsEnvironment.checkHeadless();
	s.defaultReadObject();
	}

	/**
	* Construct a name for this component. Called by getName() when the
	* name is <code>null</code>.
	*/
	String constructComponentName() {
	synchronized (Label.class) {
	return base + nameCounter++;
	}
	}

	/**
	* Creates the peer for this label. The peer allows us to
	* modify the appearance of the label without changing its
	* functionality.
	*/
	public void addNotify() {
	synchronized (getTreeLock()) {
	if (peer == null)
	peer = getToolkit().createLabel(this);
	super.addNotify();
	}
	}

	/**
	* Gets the current alignment of this label. Possible values are
	* <code>Label.LEFT</code>, <code>Label.RIGHT</code>, and
	* <code>Label.CENTER</code>.
	* @see java.awt.Label#setAlignment
	*/
	public int getAlignment() {
	return alignment;
	}

	/**
	* Sets the alignment for this label to the specified alignment.
	* Possible values are <code>Label.LEFT</code>,
	* <code>Label.RIGHT</code>, and <code>Label.CENTER</code>.
	* @param alignment the alignment to be set.
	* @exception IllegalArgumentException if an improper value for
	* <code>alignment</code> is given.
	* @see java.awt.Label#getAlignment
	*/
	public synchronized void setAlignment(int alignment) {
	switch (alignment) {
	case LEFT:
	case CENTER:
	case RIGHT:
	this.alignment = alignment;
	LabelPeer peer = (LabelPeer)this.peer;
	if (peer != null) {
	peer.setAlignment(alignment);
	}
	return;
	}
	throw new IllegalArgumentException("improper alignment: " + alignment);
	}

	/**
	* Gets the text of this label.
	* @return the text of this label, or <code>null</code> if
	* the text has been set to <code>null</code>.
	* @see java.awt.Label#setText
	*/
	public String getText() {
	return text;
	}

	/**
	* Sets the text for this label to the specified text.
	* @param text the text that this label displays. If
	* <code>text</code> is <code>null</code>, it is
	* treated for display purposes like an empty
	* string <code>""</code>.
	* @see java.awt.Label#getText
	*/
	public void setText(String text) {
	boolean testvalid = false;
	synchronized (this) {
	if (text != this.text && (this.text == null \|\|
	!this.text.equals(text))) {
	this.text = text;
	LabelPeer peer = (LabelPeer)this.peer;
	if (peer != null) {
	peer.setText(text);
	}
	testvalid = true;
	}
	}

	// This could change the preferred size of the Component.
	if (testvalid) {
	invalidateIfValid();
	}
	}

	/**
	* Returns a string representing the state of this <code>Label</code>.
	* This method is intended to be used only for debugging purposes, and the
	* content and format of the returned string may vary between
	* implementations. The returned string may be empty but may not be
	* <code>null</code>.
	*
	* @return the parameter string of this label
	*/
	protected String paramString() {
	String align = "";
	switch (alignment) {
	case LEFT: align = "left"; break;
	case CENTER: align = "center"; break;
	case RIGHT: align = "right"; break;
	}
	return super.paramString() + ",align=" + align + ",text=" + text;
	}

	/**
	* Initialize JNI field and method IDs
	*/
	private static native void initIDs();


	/////////////////
	// Accessibility support
	////////////////


	/**
	* Gets the AccessibleContext associated with this Label.
	* For labels, the AccessibleContext takes the form of an
	* AccessibleAWTLabel.
	* A new AccessibleAWTLabel instance is created if necessary.
	*
	* @return an AccessibleAWTLabel that serves as the
	* AccessibleContext of this Label
	* @since 1.3
	*/
	public AccessibleContext getAccessibleContext() {
	if (accessibleContext == null) {
	accessibleContext = new AccessibleAWTLabel();
	}
	return accessibleContext;
	}

	/**
	* This class implements accessibility support for the
	* <code>Label</code> class. It provides an implementation of the
	* Java Accessibility API appropriate to label user-interface elements.
	* @since 1.3
	*/
	protected class AccessibleAWTLabel extends AccessibleAWTComponent
	{
	/*
	* JDK 1.3 serialVersionUID
	*/
	private static final long serialVersionUID = -3568967560160480438L;

	public AccessibleAWTLabel() {
	super();
	}

	/**
	* Get the accessible name of this object.
	*
	* @return the localized name of the object -- can be null if this
	* object does not have a name
	* @see AccessibleContext#setAccessibleName
	*/
	public String getAccessibleName() {
	if (accessibleName != null) {
	return accessibleName;
	} else {
	if (getText() == null) {
	return super.getAccessibleName();
	} else {
	return getText();
	}
	}
	}

	/**
	* Get the role of this object.
	*
	* @return an instance of AccessibleRole describing the role of the object
	* @see AccessibleRole
	*/
	public AccessibleRole getAccessibleRole() {
	return AccessibleRole.LABEL;
	}

	} // inner class AccessibleAWTLabel

	}

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