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Diffstat (limited to 'db-4.8.30/examples_java/src/persist/EventExampleDPL.java')
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diff --git a/db-4.8.30/examples_java/src/persist/EventExampleDPL.java b/db-4.8.30/examples_java/src/persist/EventExampleDPL.java new file mode 100644 index 0000000..283b121 --- /dev/null +++ b/db-4.8.30/examples_java/src/persist/EventExampleDPL.java @@ -0,0 +1,273 @@ +/*- + * 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(); + } +} |