refactor update check into its own class, cf. #119

2 files changed, 89 insertions, 47 deletions

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java
new file mode 100644
index 00000000..d6e650ba
--- /dev/null
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java
@@ -0,0 +1,85 @@
+package at.asit.pdfover.gui.utils;
+
+import java.awt.Desktop;
+import java.net.URI;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import at.asit.pdfover.commons.Constants;
+import at.asit.pdfover.commons.Messages;
+import at.asit.pdfover.gui.bku.BKUHelper;
+import at.asit.pdfover.gui.controls.Dialog;
+import at.asit.pdfover.gui.controls.Dialog.BUTTONS;
+import at.asit.pdfover.gui.controls.Dialog.ICON;
+
+import org.apache.commons.httpclient.HttpClient;
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.program.Program;
+import org.eclipse.swt.widgets.Shell;
+
+public final class UpdateCheckManager {
+    static final Logger log = LoggerFactory.getLogger(UpdateCheckManager.class);
+    private static Thread updateCheckThread = null;
+    private static boolean needsCheck = false;
+
+    public static void checkNow(Shell shell) {
+        if (Constants.APP_VERSION == null)
+            return;
+
+        synchronized (UpdateCheckManager.class) {
+            if (updateCheckThread != null)
+                return;
+
+            needsCheck = true;
+            updateCheckThread = new Thread(() -> {
+                while (true) {
+                    synchronized (UpdateCheckManager.class) {
+                        if (!needsCheck) {
+                            UpdateCheckManager.updateCheckThread = null;
+                            return;
+                        }
+                        needsCheck = false;
+                    }
+                    HttpClient client = (HttpClient) BKUHelper.getHttpClient();
+                    GetMethod method = new GetMethod(Constants.CURRENT_RELEASE_URL);
+                    try {
+                        client.executeMethod(method);
+                        final String version = method.getResponseBodyAsString().trim();
+                        if (!VersionComparator.before(Constants.APP_VERSION, version))
+                            return;
+
+                        // wait 500ms before invoke the GUI message, because GUI had to be started from
+                        // main thread
+                        try { Thread.sleep(500); } catch (InterruptedException e1) { }
+                        // invoke GUI message in main thread
+                        shell.getDisplay().asyncExec(() -> {
+                            Dialog info = new Dialog(shell,
+                                    Messages.getString("version_check.UpdateTitle"),
+                                    String.format(Messages.getString("version_check.UpdateText"), version),
+                                    BUTTONS.OK_CANCEL, ICON.INFORMATION);
+
+                            if (info.open() == SWT.OK)
+                            {
+                                if (Desktop.isDesktopSupported()) {
+                                    try {
+                                        Desktop.getDesktop().browse(new URI(Constants.UPDATE_URL));
+                                    } catch (Exception e) {
+                                        log.error("Error opening update location ", e);
+                                    }
+                                } else {
+                                    log.info("SWT Desktop is not supported on this platform");
+                                    Program.launch(Constants.UPDATE_URL);
+                                }
+                            }
+                        });
+                    } catch (Exception e) {
+                        log.error("Error downloading update information: ", e);
+                    }
+                }
+            });
+            updateCheckThread.start();
+        }
+    }
+}
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/PrepareConfigurationState.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/PrepareConfigurationState.java
index b6ea9c0b..df2a82fa 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/PrepareConfigurationState.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/PrepareConfigurationState.java
@@ -16,7 +16,6 @@
 package at.asit.pdfover.gui.workflow.states;
 
 //Imports
-import java.awt.Desktop;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
@@ -27,24 +26,19 @@ import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.net.URI;
 
-import org.apache.commons.httpclient.HttpClient;
-import org.apache.commons.httpclient.methods.GetMethod;
+
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.program.Program;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import at.asit.pdfover.commons.Constants;
-import at.asit.pdfover.gui.bku.BKUHelper;
 import at.asit.pdfover.gui.cliarguments.*;
-import at.asit.pdfover.gui.controls.Dialog;
 import at.asit.pdfover.gui.controls.Dialog.BUTTONS;
-import at.asit.pdfover.gui.controls.Dialog.ICON;
 import at.asit.pdfover.gui.controls.ErrorDialog;
 import at.asit.pdfover.gui.exceptions.InitializationException;
 import at.asit.pdfover.commons.Messages;
+import at.asit.pdfover.gui.utils.UpdateCheckManager;
 import at.asit.pdfover.gui.utils.VersionComparator;
 import at.asit.pdfover.gui.utils.Zipper;
 import at.asit.pdfover.gui.workflow.GUIProvider;
@@ -301,45 +295,8 @@ public class PrepareConfigurationState extends State {
 			}
 
 			// Check for updates
-			if (config.getUpdateCheck() && Constants.APP_VERSION != null) {
-				new Thread(() -> {
-					HttpClient client = (HttpClient) BKUHelper.getHttpClient();
-					GetMethod method = new GetMethod(Constants.CURRENT_RELEASE_URL);
-					try {
-						client.executeMethod(method);
-						final String version = method.getResponseBodyAsString().trim();
-						if (!VersionComparator.before(Constants.APP_VERSION, version))
-							return;
-
-						// wait 500ms before invoke the GUI message, because GUI had to be started from
-						// main thread
-						try {Thread.sleep(500); } catch (InterruptedException e1) { }
-						// invoke GUI message in main thread
-						gui.getMainShell().getDisplay().asyncExec(() -> {
-							Dialog info = new Dialog(gui.getMainShell(),
-									Messages.getString("version_check.UpdateTitle"),
-									String.format(Messages.getString("version_check.UpdateText"), version),
-									BUTTONS.OK_CANCEL, ICON.INFORMATION);
-
-							if (info.open() == SWT.OK)
-							{
-								if (Desktop.isDesktopSupported()) {
-									try {
-										Desktop.getDesktop().browse(new URI(Constants.UPDATE_URL));
-									} catch (Exception e) {
-										log.error("Error opening update location ", e);
-									}
-								} else {
-									log.info("SWT Desktop is not supported on this platform");
-									Program.launch(Constants.UPDATE_URL);
-								}
-							}
-						});
-					} catch (Exception e) {
-						log.error("Error downloading update information: ", e);
-					}
-				}).start();
-			}
+			if (config.getUpdateCheck())
+				UpdateCheckManager.checkNow(gui.getMainShell());
 
 			// Create PDF Signer
 			Status status = stateMachine.status;