Writing offline web applications with Google Gears and GWT

3. How? GWT - Google Web Toolkit Google Gears

4. Google Web Toolkit

5. Write AJAX Applications in Java

8. Google Gears

14. Manifest File { "betaManifestVersion": 1, "version": "Version 1.0", "entries": [ { "url": "7EEF8FB6BA93DAAD0AB9A64C6D6471FE.cache.html" }, { "url": "7EEF8FB6BA93DAAD0AB9A64C6D6471FE.cache.js" }, { "url": "7EEF8FB6BA93DAAD0AB9A64C6D6471FE.cache.xml" }, { "url": "87AA9AB2FB06214DC10C32E7B35C5F6A.cache.html" }, { "url": "87AA9AB2FB06214DC10C32E7B35C5F6A.cache.js" }, { "url": "87AA9AB2FB06214DC10C32E7B35C5F6A.cache.xml" }, { "url": "884D363F8887607F5180653AA6B10E6D.cache.html" }, { "url": "884D363F8887607F5180653AA6B10E6D.cache.js" }, { "url": "884D363F8887607F5180653AA6B10E6D.cache.xml" }, { "url": "com.company.CompanyApp.nocache.js" }, { "url": "gears_init.js" }, { "url": "gwt.js" }, { "url": "CompanyApp.html" }, { "url": "default.css" }, { "url": "logo1.png" }, ] }

15. Load Resources LocalServer localServer = new LocalServer();ManagedResourceStore managedRS = localServer.createManagedResourceStore("CompanyApp"); managedRS.setManifestURL(" http://company.com/manifest.json "); managedR.checkForUpdate(); new Timer() { public void run() { switch (managedResourceStore.getUpdateStatus()) { case ManagedResourceStore.UPDATE_OK: statusLabel.setText("Ready for offline access"); break ; case ManagedResourceStore.UPDATE_CHECKING: case ManagedResourceStore.UPDATE_DOWNLOADING: schedule(500); break ; case ManagedResourceStore.UPDATE_FAILED: statusLabel.setText("Unable to go offline); break ; } } }.schedule(500);

18. Create Database private Database m_database = null; try { m_database = new Database(“Test”); ResultSet rs = m_database.execute(“create table...”); rs.close(); } // try catch (Exception e) { // Gears not installed } // catch

19. Queries String sql = “select id, first_name, last_name from person”; ResultSet rs = m_database.execute(sql); ArrayList results = new ArrayList(); while (rs.isValidRow()) { PersonBean person = new PersonBean(); person.setID(rs.getFieldAsInt(0)); person.setFirstName(rs.getFieldAsString(1)); person.setLastName(rs.getFieldAsString(2)); results.add(person); rs.next(); } // while rs.close();

20. Insert, Update String args[] = new String[3]; args[0] = Integer.toString(person.getID()); args[1] = person.getFirstName(); args[2] = person.getLastName();ResultSet rs = m_database.execute(“insert into person (id, first_name, last_name) values (?,?,?)”, args); rs.close(); args = new String[3]; args[0] = person.getFirstName(); args[1] = person.getLastName();args[2] = Integer.toString(person.getID()); rs = m_database.execute(“update person set first_name=?, last_name=? where id=?)”, args); rs.close();

21. Demo

24. Conclusion Google Gears allows web applications to run offline Google Web Toolkit makes it easy to program Gears

25. Thank You