<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns:MadCap="http://www.madcapsoftware.com/Schemas/MadCap.xsd" MadCap:lastBlockDepth="2" MadCap:lastHeight="120" MadCap:lastWidth="624" MadCap:disableMasterStylesheet="true" MadCap:tocPath="" MadCap:InPreviewMode="false" MadCap:RuntimeFileType="Topic" MadCap:TargetType="WebHelp" MadCap:PathToHelpSystem="../../../../" MadCap:HelpSystemFileName="index.xml" MadCap:SearchType="Stem">
<head><title>Code Overview </title>
<script type="text/javascript">/* <![CDATA[ */
window.onload = function(){
var pathToFlash = $('html').attr('MadCap:PathToHelpSystem') + 'Content/Resources/Code/ZeroClipboard.swf';
ZeroClipboard.setMoviePath(pathToFlash);
function bindToClipBord(element,content){
var clip = new ZeroClipboard.Client();
clip.setText(content);
clip.glue(element);
};
if(location.protocol==='file:'){
$('.copylink-marker').remove();
} else{
$('.copylink-marker').each(function(){
var text = $(this).parent().parent().children('.prettyprint').html();
$(this).hover(function(){
bindToClipBord(this,text);
},
function(){});
});
}
prettyPrint();
};
/* ]]> */</script>
<link href="../../../SkinSupport/MadCap.css" rel="stylesheet" />
<link href="../../../Resources/Stylesheets/OnlineStyle.css" rel="stylesheet" />
<script src="../../../SkinSupport/MadCapAll.js">
</script>
<script src="../../../Resources/Code/prettify.js">
</script>
<script src="../../../Resources/Code/lang-vb.js">
</script>
<script src="../../../Resources/Code/jquery.min.js">
</script>
<script src="../../../Resources/Code/ZeroClipboard.js">
</script>
</head>
<body>
<p class="MCWebHelpFramesetLink" style="display: none;"><a href="../../../../index_CSH.html#platform_specific_issues/database_for_osgi/eclipse_plug-in_with_db4o_service/code_overview.htm" style="">Open topic with navigation</a>
</p>
<p>
<script type="text/javascript">/*<![CDATA[*/document.write('<a href="' + location.href +'">');
document.write("Direct Link");
document.write('</a>');/*]]>*/</script>
</p>
<p>
</p>
<h1>Code Overview</h1>
<p>Now the plug-in environment is
configured and we can look at the code itself.</p>
<p>At this point in time the project
contains the following classes:</p>
<ul>
<li value="1">memoplugin.Activator</li>
<li value="2">memoplugin.actions.SampleAction</li>
</ul>
<p>Activator class is called to start
and stop the plug-in. It is responsible for managing its lifecycle. We will use
it to initialize and clean up db4o resources.</p>
<p>SampleAction is a class that performs the action
specified in the action set in the manifest file. It can be used to specify the
behavior on the action. We will use it to call a custom dialog for memo viewing
and editing.</p>
<p>From the said above we can see
that we will need 2 more classes:</p>
<ul>
<li value="1">Db4oProvider:
will be used to keep db4o connection, provide it to the users on request,
and close it on dispose.</li>
<li value="2">DataDialog:
will provide a simple UI for viewing and editing the data, it will use
Db4oProvider to access and store the data.</li>
</ul>
<p>These 2 classes are very basic and
are not specific to <span class="MCPopup"><a href="javascript:void(0);" class="MCPopupSpot" onclick="FMCPopup( event, this ); return false;" MadCap:src="../../database_for_osgi.htm">OSGI<img style="border: none;margin-left: 5px;" src="../../../SkinSupport/ExpandingClosed.gif" MadCap:altsrc="../../../SkinSupport/ExpandingOpen.gif" class="MCExpandingIcon" onload="if ( typeof( FMCPreloadImage ) == 'function' ) { FMCPreloadImage( '../../../SkinSupport/ExpandingOpen.gif' ); }" /></a></span> environment. Please, review their code below:</p>
<pre class="prettyprint" xml:space="preserve">Db4oProvider.java
package memoplugin;
import com.db4o.ObjectContainer;
import com.db4o.osgi.Db4oService;
/**//*
* This class is used to store db4o_osgi service instance and
* provide db4o services on request.
*/
public class Db4oProvider {
private static ObjectContainer _db;
private static String FILENAME = "sample.db4o";
public static void Initialize(Db4oService db4oService) {
_db = db4oService.openFile(FILENAME);
}
public static ObjectContainer database() {
return _db;
}
public static void UnInitialize() {
_db.close();
}
}</pre>
<pre class="prettyprint" xml:space="preserve">DataDialog.java
package memoplugin.ui;
import java.util.ArrayList;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import memoplugin.Db4oProvider;
import com.db4o.ObjectSet;
public class DataDialog extends Dialog {
private static int ID_ADD = 100;
private static int ID_DELETE = 101;
private Shell _shell;
/**
* The title of the dialog.
*/
private String title;
/**
* The message to display, or <code>null</code> if none.
*/
private String message;
/**
* The input value; the empty string by default.
*/
private String value = "";//$NON-NLS-1$
/**
* Add button widget.
*/
private Button addButton;
/**
* Delete button widget.
*/
private Button deleteButton;
/**
* Input text widget.
*/
private Text text;
/**
* List widget.
*/
private List list;
public DataDialog(Shell parentShell, String dialogTitle,
String dialogMessage, String initialValue) {
super(parentShell);
this.title = dialogTitle;
message = dialogMessage;
if (initialValue == null) {
value = "";//$NON-NLS-1$
} else {
value = initialValue;
}
}
/**
*
*
* @see org.eclipse.jface.window.
* Window#configureShell(org.eclipse.swt.widgets.Shell)
*/
protected void configureShell(Shell shell) {
super.configureShell(shell);
_shell = shell;
if (title != null) {
shell.setText(title);
}
}
/**
* Clears the database before adding new data
*/
private void clearDb() {
ObjectSet result = Db4oProvider.database().queryByExample(ArrayList.class);
while (result.hasNext()) {
Db4oProvider.database().delete(result.next());
}
}
/**
*
* Makes sure that all the data is saved to the
* database before closing the dialog
*/
protected void handleShellCloseEvent() {
clearDb();
ArrayList data = new ArrayList();
for (int i=0; i < list.getItemCount(); i++) {
data.add(list.getItem(i));
}
Db4oProvider.database().store(data);
Db4oProvider.database().commit();
Db4oProvider.database().ext().purge(ArrayList.class);
super.handleShellCloseEvent();
}
/**
* Button events handler
*/
protected void buttonPressed(int buttonId) {
if (buttonId == ID_ADD) {
value = text.getText();
list.add(value);
} else if (buttonId == ID_DELETE) {
int selectedId = list.getSelectionIndex();
if (selectedId == -1) {
new MessageDialog(_shell, "Error",
null, "No item selected", MessageDialog.ERROR,
new String[] {"Ok"}, 0).open();
} else {
list.remove(selectedId);
}
value = null;
} else {
super.buttonPressed(buttonId);
}
}
/**
*
*
* @see org.eclipse.jface.dialogs.Dialog#createButtonsForButtonBar(org.eclipse.swt.widgets.Composite)
*/
protected void createButtonsForButtonBar(Composite parent) {
// create Add and Delete buttons by default
addButton = createButton(parent, ID_ADD,
"Add", true);
createButton(parent, ID_DELETE,
"Delete", false);
//do this here because setting the text will set enablement on the ok
// button
text.setFocus();
if (value != null) {
text.setText(value);
text.selectAll();
}
}
/**
* Creates the visual dialog representation
*/
protected Control createDialogArea(Composite parent) {
// create composite
Composite composite = (Composite) super.createDialogArea(parent);
// create message
if (message != null) {
Label label = new Label(composite, SWT.WRAP);
label.setText(message);
GridData gridData = new GridData(GridData.GRAB_HORIZONTAL
| GridData.GRAB_VERTICAL | GridData.HORIZONTAL_ALIGN_FILL
| GridData.VERTICAL_ALIGN_CENTER);
gridData.widthHint = convertHorizontalDLUsToPixels(IDialogConstants.MINIMUM_MESSAGE_AREA_WIDTH);
label.setLayoutData(gridData);
label.setFont(parent.getFont());
}
text = new Text(composite, SWT.SINGLE | SWT.BORDER);
text.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL
| GridData.HORIZONTAL_ALIGN_FILL));
list = new List(composite, SWT.SINGLE|SWT.H_SCROLL|SWT.V_SCROLL);
GridData gridData = new GridData(SWT.FILL,SWT.FILL, true, true);
gridData.heightHint = 50;
list.setLayoutData(gridData);
ObjectSet result = Db4oProvider.database().query(ArrayList.class);
if (result.size() != 0) {
ArrayList data = (ArrayList)result.next();
String[] items = new String[data.size()];
for (int i=0; i < data.size(); i++) {
items[i] = (String)data.queryByExample(i);
}
list.setItems(items);
}
applyDialogFont(composite);
return composite;
}
/**
* Returns the string typed into this input dialog.
*
* @return the input string
*/
public String getValue() {
return value;
}
}</pre>
<p>In order to call the
above-mentioned DataDialog we will need to modify the generated
<code>run</code> method in SampleAction class:</p>
<pre class="prettyprint" xml:space="preserve">SampleAction.java: run
/**
* The action has been activated. The argument of the
* method represents the 'real' action sitting
* in the workbench UI.
* @see IWorkbenchWindowActionDelegate#run
*/
public void run(IAction action) {
/**
* Call DataDialog to view and edit memo notes
*/
DataDialog d = new DataDialog(window.getShell(), "db4o-osgi",
"Enter an item to add to the list:",null);
d.open();
}</pre>
<p MadCap:conditions="Primary.Online">Download example code:</p>
<script type="text/javascript" src="../../../SkinSupport/MadCapBodyEnd.js">
</script>
</body>
</html>
