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+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2004-2009 Oracle. All rights reserved.
+ *
+ * $Id$
+ */
+
+package persist;
+
+import static com.sleepycat.persist.model.Relationship.MANY_TO_ONE;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+import com.sleepycat.db.DatabaseException;
+import com.sleepycat.db.Environment;
+import com.sleepycat.db.EnvironmentConfig;
+import com.sleepycat.db.Transaction;
+import com.sleepycat.persist.EntityCursor;
+import com.sleepycat.persist.EntityStore;
+import com.sleepycat.persist.PrimaryIndex;
+import com.sleepycat.persist.SecondaryIndex;
+import com.sleepycat.persist.StoreConfig;
+import com.sleepycat.persist.model.Entity;
+import com.sleepycat.persist.model.PrimaryKey;
+import com.sleepycat.persist.model.SecondaryKey;
+
+/**
+ * EventExampleDPL is a trivial example which stores Java objects that
+ * represent an event. Events are primarily indexed by a timestamp, but have
+ * other attributes, such as price, account reps, customer name and
+ * quantity. Some of those other attributes are indexed.
+ * <p>
+ * The example simply shows the creation of a BDB environment and database,
+ * inserting some events, and retrieving the events using the Direct
+ * Persistence layer.
+ * <p>
+ * This example is meant to be paired with its twin, EventExample.java.
+ * EventExample.java and EventExampleDPL.java perform the same functionality,
+ * but use the Base API and the Direct Persistence Layer API, respectively.
+ * This may be a useful way to compare the two APIs.
+ * <p>
+ * To run the example:
+ * <pre>
+ * javac EventExampleDPL.java
+ * java EventExampleDPL -h <environmentDirectory>
+ * </pre>
+ */
+public class EventExampleDPL {
+
+ /*
+ * The Event class embodies our example event and is the application
+ * data. The @Entity annotation indicates that this class defines the
+ * objects stored in a BDB database.
+ */
+ @Entity
+ static class Event {
+
+ @PrimaryKey
+ private Date time;
+
+ @SecondaryKey(relate=MANY_TO_ONE)
+ private int price;
+
+ private Set<String> accountReps;
+
+ private String customerName;
+ private int quantity;
+
+ Event(Date time,
+ int price,
+ String customerName) {
+
+ this.time = time;
+ this.price = price;
+ this.customerName = customerName;
+ this.accountReps = new HashSet<String>();
+ }
+
+ private Event() {} // For deserialization
+
+ void addRep(String rep) {
+ accountReps.add(rep);
+ }
+
+ @Override
+ public String toString() {
+ StringBuilder sb = new StringBuilder();
+ sb.append("time=").append(time);
+ sb.append(" price=").append(price);
+ sb.append(" customerName=").append(customerName);
+ sb.append(" reps=");
+ if (accountReps.size() == 0) {
+ sb.append("none");
+ } else {
+ for (String rep: accountReps) {
+ sb.append(rep).append(" ");
+ }
+ }
+ return sb.toString();
+ }
+ }
+
+ /* A BDB environment is roughly equivalent to a relational database. */
+ private Environment env;
+ private EntityStore store;
+
+ /*
+ * Event accessors let us access events by the primary index (time)
+ * as well as by the rep and price fields
+ */
+ PrimaryIndex<Date,Event> eventByTime;
+ SecondaryIndex<Integer,Date,Event> eventByPrice;
+
+ /* Used for generating example data. */
+ private Calendar cal;
+
+ /*
+ * First manually make a directory to house the BDB environment.
+ * Usage: java EventExampleDPL -h <envHome>
+ * All BDB on-disk storage is held within envHome.
+ */
+ public static void main(String[] args)
+ throws DatabaseException, FileNotFoundException {
+
+ if (args.length != 2 || !"-h".equals(args[0])) {
+ System.err.println
+ ("Usage: java " + EventExampleDPL.class.getName() +
+ " -h <envHome>");
+ System.exit(2);
+ }
+ EventExampleDPL example = new EventExampleDPL(new File(args[1]));
+ example.run();
+ example.close();
+ }
+
+ private EventExampleDPL(File envHome)
+ throws DatabaseException, FileNotFoundException {
+
+ /* Open a transactional Berkeley DB engine environment. */
+ System.out.println("-> Creating a BDB environment");
+ EnvironmentConfig envConfig = new EnvironmentConfig();
+ envConfig.setAllowCreate(true);
+ envConfig.setTransactional(true);
+ envConfig.setInitializeCache(true);
+ envConfig.setInitializeLocking(true);
+ env = new Environment(envHome, envConfig);
+
+ /* Initialize the data access object. */
+ init();
+ cal = Calendar.getInstance();
+ }
+
+ /**
+ * Create all primary and secondary indices.
+ */
+ private void init()
+ throws DatabaseException {
+
+ /* Open a transactional entity store. */
+ System.out.println("-> Creating a BDB database");
+ StoreConfig storeConfig = new StoreConfig();
+ storeConfig.setAllowCreate(true);
+ storeConfig.setTransactional(true);
+ store = new EntityStore(env, "ExampleStore", storeConfig);
+
+ eventByTime = store.getPrimaryIndex(Date.class, Event.class);
+ eventByPrice = store.getSecondaryIndex(eventByTime,
+ Integer.class,
+ "price");
+ }
+
+ private void run()
+ throws DatabaseException {
+
+ Random rand = new Random();
+
+ /*
+ * Create a set of events. Each insertion is a separate, auto-commit
+ * transaction.
+ */
+ System.out.println("-> Inserting 4 events");
+ eventByTime.put(new Event(makeDate(1), 100, "Company_A"));
+ eventByTime.put(new Event(makeDate(2), 2, "Company_B"));
+ eventByTime.put(new Event(makeDate(3), 20, "Company_C"));
+ eventByTime.put(new Event(makeDate(4), 40, "CompanyD"));
+
+ /* Load a whole set of events transactionally. */
+ Transaction txn = env.beginTransaction(null, null);
+ int maxPrice = 50;
+ System.out.println("-> Inserting some randomly generated events");
+ for (int i = 0; i < 25; i++) {
+ Event e = new Event(makeDate(rand.nextInt(365)),
+ rand.nextInt(maxPrice),
+ "Company_X");
+ if ((i%2) ==0) {
+ e.addRep("Bob");
+ e.addRep("Nikunj");
+ } else {
+ e.addRep("Yongmin");
+ }
+ eventByTime.put(e);
+ }
+ txn.commitWriteNoSync();
+
+ /*
+ * Windows of events - display the events between June 1 and Aug 31
+ */
+ System.out.println("\n-> Display the events between June 1 and Aug 31");
+ Date startDate = makeDate(Calendar.JUNE, 1);
+ Date endDate = makeDate(Calendar.AUGUST, 31);
+
+ EntityCursor<Event> eventWindow =
+ eventByTime.entities(startDate, true, endDate, true);
+ printEvents(eventWindow);
+
+ /*
+ * Display all events, ordered by a secondary index on price.
+ */
+ System.out.println("\n-> Display all events, ordered by price");
+ EntityCursor<Event> byPriceEvents = eventByPrice.entities();
+ printEvents(byPriceEvents);
+ }
+
+ private void close()
+ throws DatabaseException {
+
+ store.close();
+ env.close();
+ }
+
+ /**
+ * Print all events covered by this cursor.
+ */
+ private void printEvents(EntityCursor<Event> eCursor)
+ throws DatabaseException {
+ try {
+ for (Event e: eCursor) {
+ System.out.println(e);
+ }
+ } finally {
+ /* Be sure to close the cursor. */
+ eCursor.close();
+ }
+ }
+
+ /**
+ * Little utility for making up java.util.Dates for different days, just
+ * to generate test data.
+ */
+ private Date makeDate(int day) {
+
+ cal.set((Calendar.DAY_OF_YEAR), day);
+ return cal.getTime();
+ }
+
+ /**
+ * Little utility for making up java.util.Dates for different days, just
+ * to make the test data easier to read.
+ */
+ private Date makeDate(int month, int day) {
+
+ cal.set((Calendar.MONTH), month);
+ cal.set((Calendar.DAY_OF_MONTH), day);
+ return cal.getTime();
+ }
+}
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