2
edits
Changes
client bundle
</source>
<h6> 2.1 2 Create the SimpleVotingSystem.java </h6>
This is the internal implementation of the service and should be done in a packet that will not be exported.
public int[] countVotesFor(String code) {
// dirty simple and trivial implementation of a voting system
String[] votCodes = { "default", "yesno", "yeahnah", "ync" };
for (int i = 0; i < votes.length; i++) {
Import-Package: cs.ecl.osgi.voting,
org.osgi.framework;version="1.3.0"
</source>
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<h4> 3. Define the Service Consumer (the voter)</h4>
Create the bundle ''cs.ecl.osgi.votingsystem.client_1.0.0.qualifier''. This bundle will have a GUI for letting the voter to exercise his/her public duties.
<h6> 3.1 Create the ClientActivator.java </h6>
<source lang="java">
package cs.ecl.osgi.votingsystem.client;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import cs.ecl.osgi.voting.VotingSystem;
public class ClientActivator implements BundleActivator {
private static BundleContext context;
private VotingSystem vs;
static BundleContext getContext() {
return context;
}
public void start(BundleContext bundleContext) throws Exception {
ClientActivator.context = bundleContext;
ServiceReference reference = context
.getServiceReference(VotingSystem.class.getName());
if (reference != null) {
vs = (VotingSystem) context.getService(reference);
if (vs != null) {
// invoke GUI
VoteDialog.runDialog(vs);
context.ungetService(reference);
} else
System.err.println("the Voting Sytem cannot be used !!!");
} else
System.err.println("the Voting Sytem cannot be found !!!");
}
public void stop(BundleContext bundleContext) throws Exception {
ClientActivator.context = null;
}
}
</source>
If the VotingSystem object is retrieved from the OSGi system, then a dialog box is created and the object is sent to GUI.
<h6> 3.2 Create the VoteDialog.java </h6>
<source lang="java">
package cs.ecl.osgi.votingsystem.client;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import cs.ecl.osgi.voting.VotingSystem;
public class VoteDialog extends JPanel {
JLabel label;
JFrame frame;
String simpleDialogDesc = "The candidates";
static VotingSystem vs;
static int[] votesSoFar = new int[4];
public VoteDialog(JFrame frame) {
super(new BorderLayout());
this.frame = frame;
JLabel title;
// Create the components.
JPanel choicePanel = createSimpleDialogBox();
System.out.println("passed createSimpleDialogBox");
title = new JLabel("Click the \"Vote\" button"
+ " once you have selected a candidate.", JLabel.CENTER);
label = new JLabel("Vote now!", JLabel.CENTER);
label.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
choicePanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 5, 20));
// Lay out the main panel.
add(title, BorderLayout.NORTH);
add(label, BorderLayout.SOUTH);
add(choicePanel, BorderLayout.CENTER);
}
void setLabel(String newText) {
label.setText(newText);
}
private JPanel createSimpleDialogBox() {
final int numButtons = 4;
JRadioButton[] radioButtons = new JRadioButton[numButtons];
final ButtonGroup group = new ButtonGroup();
JButton voteButton = null;
final String defaultMessageCommand = "default";
final String yesNoCommand = "yesno";
final String yeahNahCommand = "yeahnah";
final String yncCommand = "ync";
radioButtons[0] = new JRadioButton(
"<html>Candidate 1: <font color=red>Sparky the Dog</font></html>");
radioButtons[0].setActionCommand(defaultMessageCommand);
radioButtons[1] = new JRadioButton(
"<html>Candidate 2: <font color=green>Shady Sadie</font></html>");
radioButtons[1].setActionCommand(yesNoCommand);
radioButtons[2] = new JRadioButton(
"<html>Candidate 3: <font color=blue>R.I.P. McDaniels</font></html>");
radioButtons[2].setActionCommand(yeahNahCommand);
radioButtons[3] = new JRadioButton(
"<html>Candidate 4: <font color=maroon>Duke the Java<font size=-2></font size> Platform Mascot</font></html>");
radioButtons[3].setActionCommand(yncCommand);
for (int i = 0; i < numButtons; i++) {
group.add(radioButtons[i]);
}
// Select the first button by default.
radioButtons[0].setSelected(true);
voteButton = new JButton("Vote");
voteButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String command = group.getSelection().getActionCommand();
System.out.println("SELECTION " + command);
// ok dialog
if (command == defaultMessageCommand) {
JOptionPane.showMessageDialog(frame,
"This candidate is a dog. Invalid vote.");
votesSoFar = vs.countVotesFor(defaultMessageCommand);
printVotes(votesSoFar);
// yes/no dialog
} else if (command == yesNoCommand) {
int n = JOptionPane
.showConfirmDialog(
frame,
"This candidate is a convicted felon. \nDo you still want to vote for her?",
"A Follow-up Question",
JOptionPane.YES_NO_OPTION);
if (n == JOptionPane.YES_OPTION) {
setLabel("OK. Keep an eye on your wallet.");
printVotes(vs.countVotesFor(yesNoCommand));
} else if (n == JOptionPane.NO_OPTION) {
setLabel("Whew! Good choice.");
} else {
setLabel("It is your civic duty to cast your vote.");
}
// yes/no (with customized wording)
} else if (command == yeahNahCommand) {
Object[] options = { "Yes, please", "No, thanks" };
int n = JOptionPane
.showOptionDialog(
frame,
"This candidate is deceased. \nDo you still want to vote for him?",
"A Follow-up Question",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE, null,
options, options[0]);
if (n == JOptionPane.YES_OPTION) {
setLabel("I hope you don't expect much from your candidate.");
printVotes(vs.countVotesFor(yeahNahCommand));
} else if (n == JOptionPane.NO_OPTION) {
setLabel("Whew! Good choice.");
} else {
setLabel("It is your civic duty to cast your vote.");
}
// yes/no/cancel (with customized wording)
} else if (command == yncCommand) {
Object[] options = { "Yes!", "No, I'll pass",
"Well, if I must" };
int n = JOptionPane.showOptionDialog(frame,
"Duke is a cartoon mascot. \nDo you "
+ "still want to cast your vote?",
"A Follow-up Question",
JOptionPane.YES_NO_CANCEL_OPTION,
JOptionPane.QUESTION_MESSAGE, null, options,
options[2]);
if (n == JOptionPane.YES_OPTION) {
setLabel("Excellent choice.");
printVotes(vs.countVotesFor(yncCommand));
} else if (n == JOptionPane.NO_OPTION) {
setLabel("Whatever you say. It's your vote.");
} else if (n == JOptionPane.CANCEL_OPTION) {
setLabel("Well, I'm certainly not going to make you vote.");
} else {
setLabel("It is your civic duty to cast your vote.");
}
}
return;
}
private void printVotes(int[] votesSoFar) {
for (int i = 0; i < votesSoFar.length; i++)
System.out.println(" Candidate = " + (i + 1) + " has "
+ votesSoFar[i]);
}
});
System.out.println("calling createPane");
return createPane(simpleDialogDesc + ":", radioButtons, voteButton);
}
private JPanel createPane(String description, JRadioButton[] radioButtons,
JButton showButton) {
int numChoices = radioButtons.length;
JPanel box = new JPanel();
JLabel label = new JLabel(description);
box.setLayout(new BoxLayout(box, BoxLayout.PAGE_AXIS));
box.add(label);
for (int i = 0; i < numChoices; i++) {
box.add(radioButtons[i]);
}
JPanel pane = new JPanel(new BorderLayout());
pane.add(box, BorderLayout.NORTH);
pane.add(showButton, BorderLayout.SOUTH);
System.out.println("returning pane");
return pane;
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
private static void createAndShowGUI(VotingSystem vs) {
// Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
JDialog.setDefaultLookAndFeelDecorated(true);
// Create and set up the window.
JFrame frame = new JFrame("VoteDialog");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Set up the content pane.
Container contentPane = frame.getContentPane();
contentPane.setLayout(new GridLayout(1, 1));
contentPane.add(new VoteDialog(frame));
VoteDialog.vs = vs;
// Display the window.
frame.pack();
frame.setVisible(true);
}
public static void runDialog(final VotingSystem vs) {
// Schedule a job for the event-dispatching thread:
// creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI(vs);
}
});
}
}
</source>
<h6> 3.3 Define the MANIFEST.MF for the service consumer</h6>
<source lang="xml">
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Voting System Client
Bundle-SymbolicName: cs.ecl.osgi.votingsystem.client
Bundle-Version: 1.0.0.qualifier
Bundle-Activator: cs.ecl.osgi.votingsystem.client.ClientActivator
Bundle-Vendor: Seneca College - Eclipse Course
Bundle-RequiredExecutionEnvironment: JavaSE-1.6
Import-Package: cs.ecl.osgi.voting,
org.osgi.framework;version="1.3.0"
</source>
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