J2ME DATA MANAGEMENT in Java

Make PDF417 in Java J2ME DATA MANAGEMENT

2 Create instances of classes and assign those instances to references 3 Open a record store and create a new record store if the record store doesn t exist 4 Display any errors that occur when opening/creating a record store 5 Create data in the appropriate data type 6 Convert data to a byte array output stream 7 Create a data output stream using the byte array output stream 8 Write each column of the record to the data output stream 9 Convert the data output stream to a byte array 10 Write the record to the record store 11 Close the output byte array output stream and the data output stream 12 Display any errors that might occur while writing to the record store 13 Create a buffer of bytes sufficient to hold a record 14 Create a byte array input stream and a data input stream 15 Create a Filter class with a method that compares the search criteria to a record and returns a boolean value true or false If true, then include the record in the RecordEnumeration 16 Create an instance of the Filter class and use the instance when creating the RecordEnumeration 17 Loop through the RecordEnumeration, copying each column from the record store to a variable 18 Display the data in a dialog box 19 Display any errors that occur when reading records from the record store 20 Close and remove the RecordEnumeration and the record store

The last method defined in the Filter class implementation of the RecordFilter is the filterClose() method This method, called in the fifth try {} block, closes the input stream and data input stream used by the Filter class

Listing 8-17 Searching a mixed data type import javaxmicroeditionrms*; import javaxmicroeditionmidlet*; import javaxmicroeditionlcdui*;

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import javaio*; public class SearchMixedRecordDataTypeExample extends MIDlet implements CommandListener { private Display display; private Alert alert; private Form form; private Command exit; private Command start; private RecordStore recordstore = null; private RecordEnumeration recordEnumeration = null; private Filter filter = null; public SearchMixedRecordDataTypeExample () { display = DisplaygetDisplay(this); exit = new Command("Exit", CommandSCREEN, 1); start = new Command("Start", CommandSCREEN, 1); form = new Form("Mixed RecordEnumeration"); formaddCommand(exit); formaddCommand(start); formsetCommandListener(this); } public void startApp() { displaysetCurrent(form); } public void pauseApp() { } public void destroyApp( boolean unconditional ) { } public void commandAction(Command command, Displayable displayable) { if (command == exit) { destroyApp(true); notifyDestroyed(); } else if (command == start) { try { recordstore = RecordStoreopenRecordStore( "myRecordStore", true ); } catch (Exception error) { alert = new Alert("Error Creating",

errortoString(), null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } try { byte[] outputRecord; String outputString[] = {"Adam", "Bob", "Mary"}; int outputInteger[] = {15, 10, 5}; ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); DataOutputStream outputDataStream = new DataOutputStream(outputStream); for (int x = 0; x < 3; x++) { outputDataStreamwriteUTF(outputString[x]); outputDataStreamwriteInt(outputInteger[x]); outputDataStreamflush(); outputRecord = outputStreamtoByteArray(); recordstoreaddRecord(outputRecord, 0, outputRecordlength); outputStreamreset(); } outputStreamclose(); outputDataStreamclose(); } catch ( Exception error) { alert = new Alert("Error Writing", errortoString(), null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } try { String inputString; byte[] byteInputData = new byte[300]; ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData); DataInputStream inputDataStream = new DataInputStream(inputStream); if (recordstoregetNumRecords() > 0) { filter = new Filter("Mary"); recordEnumeration = recordstoreenumerateRecords( filter, null, false); while (recordEnumerationhasNextElement()) { recordstoregetRecord(recordEnumerationnextRecordId(),

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byteInputData, 0); inputString = inputDataStreamreadUTF() + " " + inputDataStreamreadInt(); alert = new Alert("Reading", inputString, null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } } inputStreamclose(); } catch (Exception error) { alert = new Alert("Error Reading", errortoString(), null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } try { recordstorecloseRecordStore(); } catch (Exception error) { alert = new Alert("Error Closing", errortoString(), null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } if (RecordStorelistRecordStores() != null) { try { RecordStoredeleteRecordStore("myRecordStore"); filterfilterClose(); recordEnumerationdestroy(); } catch (Exception error) { alert = new Alert("Error Removing", errortoString(), null, AlertTypeWARNING); alertsetTimeout(AlertFOREVER); displaysetCurrent(alert); } } } }