001: /*
002: * This file is part of the Echo Web Application Framework (hereinafter "Echo").
003: * Copyright (C) 2002-2005 NextApp, Inc.
004: *
005: * Version: MPL 1.1/GPL 2.0/LGPL 2.1
006: *
007: * The contents of this file are subject to the Mozilla Public License Version
008: * 1.1 (the "License"); you may not use this file except in compliance with
009: * the License. You may obtain a copy of the License at
010: * http://www.mozilla.org/MPL/
011: *
012: * Software distributed under the License is distributed on an "AS IS" basis,
013: * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
014: * for the specific language governing rights and limitations under the
015: * License.
016: *
017: * Alternatively, the contents of this file may be used under the terms of
018: * either the GNU General Public License Version 2 or later (the "GPL"), or
019: * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
020: * in which case the provisions of the GPL or the LGPL are applicable instead
021: * of those above. If you wish to allow use of your version of this file only
022: * under the terms of either the GPL or the LGPL, and not to allow others to
023: * use your version of this file under the terms of the MPL, indicate your
024: * decision by deleting the provisions above and replace them with the notice
025: * and other provisions required by the GPL or the LGPL. If you do not delete
026: * the provisions above, a recipient may use your version of this file under
027: * the terms of any one of the MPL, the GPL or the LGPL.
028: */
029:
030: package nextapp.echo2.app.button;
031:
032: import java.io.Serializable;
033: import java.util.HashSet;
034: import java.util.Iterator;
035: import java.util.Set;
036:
037: import nextapp.echo2.app.ApplicationInstance;
038: import nextapp.echo2.app.RenderIdSupport;
039: import nextapp.echo2.app.RadioButton;
040:
041: /**
042: * A collection of radio buttons which allows the selection of only one
043: * radio button at a time.
044: */
045: public class ButtonGroup implements RenderIdSupport, Serializable {
046:
047: private static final RadioButton[] EMPTY = new RadioButton[0];
048:
049: private String id = ApplicationInstance.generateSystemId();
050: private Set buttons;
051:
052: /**
053: * Adds a <code>RadioButton</code> to the group.
054: * Applications should use <code>RadioButton.setGroup()</code> to add
055: * buttons from a group rather than invoking this method.
056: *
057: * @param radioButton the <code>RadioButton</code> to add
058: * @see RadioButton#setGroup(ButtonGroup)
059: */
060: public void addButton(RadioButton radioButton) {
061: if (buttons == null) {
062: buttons = new HashSet();
063: }
064: buttons.add(radioButton);
065: updateSelection(radioButton);
066: }
067:
068: /**
069: * Returns all <code>RadioButton</code>s in the group.
070: *
071: * @return the <code>RadioButton</code>
072: */
073: public RadioButton[] getButtons() {
074: if (buttons == null) {
075: return EMPTY;
076: } else {
077: return (RadioButton[]) buttons
078: .toArray(new RadioButton[buttons.size()]);
079: }
080: }
081:
082: /**
083: * @see nextapp.echo2.app.RenderIdSupport#getRenderId()
084: */
085: public String getRenderId() {
086: return id;
087: }
088:
089: /**
090: * Removes a <code>RadioButton</code> from the group.
091: * Applications should use <code>RadioButton.setGroup()</code> to remove
092: * buttons from a group rather than invoking this method.
093: *
094: * @param radioButton the <code>RadioButton</code> to remove
095: * @see RadioButton#setGroup(ButtonGroup)
096: */
097: public void removeButton(RadioButton radioButton) {
098: if (buttons != null) {
099: buttons.remove(radioButton);
100: }
101: }
102:
103: /**
104: * Notifies the <code>ButtonGroup</code> that a <code>RadioButton</code>
105: * within its domain may have changed state.
106: *
107: * @param changedButton the changed <code>RadioButton</code>
108: */
109: public void updateSelection(RadioButton changedButton) {
110: if (buttons == null || !changedButton.isSelected()) {
111: return;
112: }
113: Iterator buttonIt = buttons.iterator();
114: while (buttonIt.hasNext()) {
115: RadioButton button = (RadioButton) buttonIt.next();
116: if (!button.equals(changedButton)) {
117: button.setSelected(false);
118: }
119: }
120: }
121: }
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