/*
* @(#)RMSGameScores.java 1.6 02/07/25 @(#)
*
* Copyright (c) 1998-2001 Sun Microsystems, Inc. All rights reserved.
* PROPRIETARY/CONFIDENTIAL
* Use is subject to license terms.
*/
/**
* This sample code is from the javax.microedition.rms package overview
* in the public draft of the MIDP spec.
* It has been modified only slightly to be run as a MIDlet rather than
* a class with a static main() entry point.
*/
/*
* <p>The Mobile Information Device Profile provides a mechanism for
* MIDlets to persistently store data and later retrieve it. This
* persistent storage mechanism is modeled after a simple record oriented
* database and is called the Record Management System.
* <p><b>Example:</b>
* <p>The example uses the Record Management System to store and retrieve
* high scores for a game. In the example, high scores are stored in
* separate records, and sorted when necessary using a RecordEnumeration.
*/
package example;
import javax.microedition.midlet.*;
import javax.microedition.rms.*;
import java.io.DataOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
/**
* A class used for storing and showing game scores.
*/
public class RMSGameScores extends MIDlet
implements RecordFilter, RecordComparator
{
private RMSGameScores rmsgs = null;
/*
* The RecordStore used for storing the game scores.
*/
private RecordStore recordStore = null;
/*
* The player name to use when filtering.
*/
public static String playerNameFilter = null;
/*
* Part of the RecordFilter interface.
*/
public boolean matches(byte[] candidate)
throws IllegalArgumentException
{
// If no filter set, nothing can match it.
if (this.playerNameFilter == null) {
return false;
}
ByteArrayInputStream bais = new ByteArrayInputStream(candidate);
DataInputStream inputStream = new DataInputStream(bais);
String name = null;
try {
int score = inputStream.readInt();
name = inputStream.readUTF();
}
catch (EOFException eofe) {
System.out.println(eofe);
eofe.printStackTrace();
}
catch (IOException eofe) {
System.out.println(eofe);
eofe.printStackTrace();
}
return (this.playerNameFilter.equals(name));
}
/*
* Part of the RecordComparator interface.
*/
public int compare(byte[] rec1, byte[] rec2)
{
// Construct DataInputStreams for extracting the scores from
// the records.
ByteArrayInputStream bais1 = new ByteArrayInputStream(rec1);
DataInputStream inputStream1 = new DataInputStream(bais1);
ByteArrayInputStream bais2 = new ByteArrayInputStream(rec2);
DataInputStream inputStream2 = new DataInputStream(bais2);
int score1 = 0;
int score2 = 0;
try {
// Extract the scores.
score1 = inputStream1.readInt();
score2 = inputStream2.readInt();
}
catch (EOFException eofe) {
System.out.println(eofe);
eofe.printStackTrace();
}
catch (IOException eofe) {
System.out.println(eofe);
eofe.printStackTrace();
}
// Sort by score
if (score1 < score2) {
return RecordComparator.PRECEDES;
} else if (score1 > score2) {
return RecordComparator.FOLLOWS;
} else {
return RecordComparator.EQUIVALENT;
}
}
/**
* The constructor opens the underlying record store,
* creating it if necessary.
*/
public RMSGameScores()
{
//
// Create a new record store for this example
//
try {
recordStore = RecordStore.openRecordStore("scores", true);
}
catch (RecordStoreException rse) {
System.out.println(rse);
rse.printStackTrace();
}
}
/**
* Add a new score to the storage.
*
* @param score the score to store.
* @param playerName the name of the play achieving this score.
*/
public void addScore(int score, String playerName)
{
//
// Each score is stored in a separate record, formatted with
// the score, followed by the player name.
//
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream outputStream = new DataOutputStream(baos);
try {
// Push the score into a byte array.
outputStream.writeInt(score);
// Then push the player name.
outputStream.writeUTF(playerName);
}
catch (IOException ioe) {
System.out.println(ioe);
ioe.printStackTrace();
}
// Extract the byte array
byte[] b = baos.toByteArray();
// Add it to the record store
try {
recordStore.addRecord(b, 0, b.length);
}
catch (RecordStoreException rse) {
System.out.println(rse);
rse.printStackTrace();
}
}
/**
* A helper method for the printScores methods.
*/
private void printScoresHelper(RecordEnumeration re)
{
try {
while (re.hasNextElement()) {
int id = re.nextRecordId();
ByteArrayInputStream bais = new
ByteArrayInputStream(recordStore.getRecord(id));
DataInputStream inputStream = new DataInputStream(bais);
try {
int score = inputStream.readInt();
String playerName = inputStream.readUTF();
System.out.println(playerName + " = " + score);
}
catch (EOFException eofe) {
System.out.println(eofe);
eofe.printStackTrace();
}
}
}
catch (RecordStoreException rse) {
System.out.println(rse);
rse.printStackTrace();
}
catch (IOException ioe) {
System.out.println(ioe);
ioe.printStackTrace();
}
}
/**
* This method prints all of the scores sorted by game score.
*/
public void printScores()
{
try {
// Enumerate the records using the comparator implemented
// above to sort by game score.
RecordEnumeration re = recordStore.enumerateRecords(null, this,
true);
printScoresHelper(re);
}
catch (RecordStoreException rse) {
System.out.println(rse);
rse.printStackTrace();
}
}
/**
* This method prints all of the scores for a given player,
* sorted by game score.
*/
public void printScores(String playerName)
{
try {
// Enumerate the records using the comparator and filter
// implemented above to sort by game score.
RecordEnumeration re = recordStore.enumerateRecords(this, this,
true);
printScoresHelper(re);
}
catch (RecordStoreException rse) {
System.out.println(rse);
rse.printStackTrace();
}
}
public void main()
{
rmsgs = new RMSGameScores();
rmsgs.addScore(100, "Alice");
rmsgs.addScore(120, "Bill");
rmsgs.addScore(80, "Candice");
rmsgs.addScore(40, "Dean");
rmsgs.addScore(200, "Ethel");
rmsgs.addScore(110, "Farnsworth");
rmsgs.addScore(220, "Farnsworth");
System.out.println("All scores");
rmsgs.printScores();
System.out.println("Farnsworth's scores");
RMSGameScores.playerNameFilter = "Farnsworth";
rmsgs.printScores("Farnsworth");
}
/*
* These three methods are required because we claim to extend
* the abstract MIDlet class;
*/
/**
* startApp()
*/
public void startApp() throws MIDletStateChangeException {
System.out.println("startApp() - invoking main");
// main() output is to System.out
main();
}
/**
* pauseApp()
*/
public void pauseApp() {
System.out.println("pauseApp()");
}
/**
* destroyApp()
*
* This closes our open RecordStore when we are destroyed.
* @param cond true if this is an unconditional destroy
* false if it is not
* (ignored here and treated as unconditional)
*/
public void destroyApp(boolean cond) {
System.out.println("destroyApp()");
try {
if (recordStore != null)
recordStore.closeRecordStore();
} catch (Exception ignore) {
// ignore this
}
}
}
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