conient/datacomponents/UsersDataComponent.java

//---PACKAGE DECLARATION---
package uk.ac.ukc.iscream.conient.datacomponents;

//---IMPORTS---
import javax.swing.JLabel;
import java.awt.GridLayout;
import java.util.Date;
import java.util.StringTokenizer;
import javax.swing.JComboBox;
import java.text.DateFormat;
import javax.swing.SwingUtilities;

/**
 * This component displays the users currently logged
 * onto a system.  Currently it does this simply by 
 * putting them all in a JCombobox.
 *
 * @author  $Author: tdb1 $
 * @version $Id: UsersDataComponent.java,v 1.8 2001/01/29 14:00:51 tdb1 Exp $
 */
public class UsersDataComponent extends VisibleDataComponent {

//---FINAL ATTRIBUTES---

//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Creates the component with a friendly name to be 
     * used as label, but as we're a very basic
     * extension of StringDataComponent, we just construct
     * that.
     *
     * @param name the friendly name
     * @param attribute the data attribute we look after
     */
    public UsersDataComponent(String name, String attribute) {
        _name = name;
        _attribute = attribute;
        _label = new JLabel(name + ": ");
        _label.setHorizontalAlignment(JLabel.RIGHT);
        setLayout(new GridLayout(1, 2));
        _item.addItem("-uninitialised-");
        add(_label);
        add(_item);
    }

//---PUBLIC METHODS---
    
    /**
     * This run method updates any Swing components
     * The setValue() method adds this component
     * to the Swing Event Dispatching Queue to
     * run this method.
     */
    public void run() {
            _item.removeAllItems();
            if (_cache.equals(" ")) {
                _item.addItem("no users logged on");
        } else {
            StringTokenizer st = new StringTokenizer(_cache);
            while(st.hasMoreTokens()) {
                _item.addItem(st.nextToken());
            }
        }
    }

    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return _name + "(" + _attribute + ")";
    }

//---PRIVATE METHODS---

//---ACCESSOR/MUTATOR METHODS---
     
    /**
     * This takes the String value of the parameter that this component
     * is monitoring direct from the packet, it then performs all
     * approriate conversions and adds this class to the Swing Event
     * Dispatching queue.
     *
     * @param value the value for this data component
     * @throws DataFormatException if there was a problem converting the data for display
     */
    public void setValue(String value) throws DataFormatException {
        try {
            if (!_cache.equals(value)) {
                _cache = value;
                SwingUtilities.invokeLater(this);
            }
        } catch (Exception e) {
            throw new DataFormatException(value + " is an invalid data type for " + toString());
        }
    }        

//---ATTRIBUTES---

    /**
     * The friendly name of this component
     */
    private String _name;
    
    /**
     * The attribute that this component is concerned with
     */
    private String _attribute;
    
    /**
     * Remebers what the last value was, so we
     * only update if we have to.
     */ 
    String _cache = "";

    /**
     * The friendly label for this component
     */
    protected JLabel _label;
    
    /**
     * Just a JComboBox to display the users in
     */
    protected JComboBox _item = new JComboBox();

//---STATIC ATTRIBUTES---

}
Revision:	1.9
Committed:	Tue Jan 30 03:23:01 2001 UTC (23 years, 3 months ago) by ajm
Branch:	MAIN
Changes since 1.8:	+10 -9 lines
Log Message:	now displays "no users logged in" if it detects no users logged in
#	Content
1	//---PACKAGE DECLARATION---
2	package uk.ac.ukc.iscream.conient.datacomponents;
3
4	//---IMPORTS---
5	import javax.swing.JLabel;
6	import java.awt.GridLayout;
7	import java.util.Date;
8	import java.util.StringTokenizer;
9	import javax.swing.JComboBox;
10	import java.text.DateFormat;
11	import javax.swing.SwingUtilities;
12
13	/**
14	* This component displays the users currently logged
15	* onto a system. Currently it does this simply by
16	* putting them all in a JCombobox.
17	*
18	* @author $Author: tdb1 $
19	* @version $Id: UsersDataComponent.java,v 1.8 2001/01/29 14:00:51 tdb1 Exp $
20	*/
21	public class UsersDataComponent extends VisibleDataComponent {
22
23	//---FINAL ATTRIBUTES---
24
25	//---STATIC METHODS---
26
27	//---CONSTRUCTORS---
28
29	/**
30	* Creates the component with a friendly name to be
31	* used as label, but as we're a very basic
32	* extension of StringDataComponent, we just construct
33	* that.
34	*
35	* @param name the friendly name
36	* @param attribute the data attribute we look after
37	*/
38	public UsersDataComponent(String name, String attribute) {
39	_name = name;
40	_attribute = attribute;
41	_label = new JLabel(name + ": ");
42	_label.setHorizontalAlignment(JLabel.RIGHT);
43	setLayout(new GridLayout(1, 2));
44	_item.addItem("-uninitialised-");
45	add(_label);
46	add(_item);
47	}
48
49	//---PUBLIC METHODS---
50
51	/**
52	* This run method updates any Swing components
53	* The setValue() method adds this component
54	* to the Swing Event Dispatching Queue to
55	* run this method.
56	*/
57	public void run() {
58	_item.removeAllItems();
59	if (_cache.equals(" ")) {
60	_item.addItem("no users logged on");
61	} else {
62	StringTokenizer st = new StringTokenizer(_cache);
63	while(st.hasMoreTokens()) {
64	_item.addItem(st.nextToken());
65	}
66	}
67	}
68
69	/**
70	* Overrides the {@link java.lang.Object#toString() Object.toString()}
71	* method to provide clean logging (every class should have this).
72	*
73	* @return the name of this class and its CVS revision
74	*/
75	public String toString() {
76	return _name + "(" + _attribute + ")";
77	}
78
79	//---PRIVATE METHODS---
80
81	//---ACCESSOR/MUTATOR METHODS---
82
83	/**
84	* This takes the String value of the parameter that this component
85	* is monitoring direct from the packet, it then performs all
86	* approriate conversions and adds this class to the Swing Event
87	* Dispatching queue.
88	*
89	* @param value the value for this data component
90	* @throws DataFormatException if there was a problem converting the data for display
91	*/
92	public void setValue(String value) throws DataFormatException {
93	try {
94	if (!_cache.equals(value)) {
95	_cache = value;
96	SwingUtilities.invokeLater(this);
97	}
98	} catch (Exception e) {
99	throw new DataFormatException(value + " is an invalid data type for " + toString());
100	}
101	}
102
103	//---ATTRIBUTES---
104
105	/**
106	* The friendly name of this component
107	*/
108	private String _name;
109
110	/**
111	* The attribute that this component is concerned with
112	*/
113	private String _attribute;
114
115	/**
116	* Remebers what the last value was, so we
117	* only update if we have to.
118	*/
119	String _cache = "";
120
121	/**
122	* The friendly label for this component
123	*/
124	protected JLabel _label;
125
126	/**
127	* Just a JComboBox to display the users in
128	*/
129	protected JComboBox _item = new JComboBox();
130
131	//---STATIC ATTRIBUTES---
132
133	}