/*
* @(#)Label.java 1.42 06/10/10
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package java.awt;
import sun.awt.peer.LabelPeer;
import sun.awt.PeerBasedToolkit;
/**
* 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 . . .
* <p>
* <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 label:
* <p>
* <img src="images-awt/Label-1.gif"
* ALIGN=center HSPACE=10 VSPACE=7>
*
* @version 1.31, 07/01/98
* @author Sami Shaio
* @since JDK1.0
*/
public class Label extends Component {
/**
* Indicates that the label should be left justified.
* @since JDK1.0
*/
public static final int LEFT = 0;
/**
* Indicates that the label should be centered.
* @since JDK1.0
*/
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.
*/
String text;
/**
* The label's alignment. The default alignment is set
* to be left justified.
*/
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.
* @since JDK1.0
*/
public Label() {
this("", LEFT);
}
/**
* Constructs a new label with the specified string of text,
* left justified.
* @param text the string that the label presents.
* @since JDK1.0
*/
public Label(String text) {
this(text, LEFT);
}
/**
* Constructs a new label that presents the specified string of
* text with the specified alignment.
* <p>
* 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.
* @param alignment the alignment value.
* @since JDK1.0
*/
public Label(String text, int alignment) {
this.text = text;
setAlignment(alignment);
}
/**
* Construct a name for this component. Called by getName() when the
* name is null.
*/
String constructComponentName() {
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 = ((PeerBasedToolkit) 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
* @since JDK1.0
*/
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
* @since JDK1.0
*/
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.
* @see java.awt.Label#setText
* @since JDK1.0
*/
public String getText() {
return text;
}
/**
* Sets the text for this label to the specified text.
* @param text the text that this label presents.
* @see java.awt.Label#getText
* @since JDK1.0
*/
public synchronized void setText(String text) {
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);
}
}
}
/**
* Returns the parameter string representing the state of this
* label. This string is useful for debugging.
* @return the parameter string of this label.
* @since JDK1.0
*/
protected String paramString() {
String str = ",align=";
switch (alignment) {
case LEFT:
str += "left";
break;
case CENTER:
str += "center";
break;
case RIGHT:
str += "right";
break;
}
return super.paramString() + str + ",text=" + text;
}
}