面向 Java 开发人员的 db4o 指南

                package com.tedneward.model;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, int age)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }

    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "age = " + age + 
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private int age;
}

                import com.db4o.*;

import com.tedneward.model.*;

public class Hellodb4o
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person brian = new Person("Brian", "Goetz", 39);
            
            db.set(brian);
            db.commit();
        }
        finally
        {
            if (db != null)
                db.close();
        }
    }
}

                import com.db4o.*;

import com.tedneward.model.*;

public class Hellodb4o
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person brian = new Person("Brian", "Goetz", 39);
            Person jason = new Person("Jason", "Hunter", 35);
            Person clinton = new Person("Brian", "Sletten", 38);
            Person david = new Person("David", "Geary", 55);
            Person glenn = new Person("Glenn", "Vanderberg", 40);
            Person neal = new Person("Neal", "Ford", 39);
            
            db.set(brian);
            db.set(jason);
            db.set(clinton);
            db.set(david);
            db.set(glenn);
            db.set(neal);

            db.commit();
            
            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0));
            while (brians.hasNext())
                System.out.println(brians.next());
        }
        finally
        {
            if (db != null)
                db.close();
        }
    }
}

                package com.tedneward.model;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, int age)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }

    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "age = " + age + 
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private int age;
}

                import com.db4o.*;

import com.tedneward.model.*;

public class Hellodb4o
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person brian = new Person("Brian", "Goetz", 39);
            Person jason = new Person("Jason", "Hunter", 35);
            Person clinton = new Person("Brian", "Sletten", 38);
            Person david = new Person("David", "Geary", 55);
            Person glenn = new Person("Glenn", "Vanderberg", 40);
            Person neal = new Person("Neal", "Ford", 39);
            
            db.set(brian);
            db.set(jason);
            db.set(clinton);
            db.set(david);
            db.set(glenn);
            db.set(neal);

            db.commit();
            
            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0));
            while (brians.hasNext())
                System.out.println(brians.next());
        }
        finally
        {
            if (db != null)
                db.close();
        }
    }
}

                import com.db4o.*;

import com.tedneward.model.*;

public class Hellodb4o
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person brian = new Person("Brian", "Goetz", 39);
            Person jason = new Person("Jason", "Hunter", 35);
            Person clinton = new Person("Brian", "Sletten", 38);
            Person david = new Person("David", "Geary", 55);
            Person glenn = new Person("Glenn", "Vanderberg", 40);
            Person neal = new Person("Neal", "Ford", 39);
            
            db.set(brian);
            db.set(jason);
            db.set(clinton);
            db.set(david);
            db.set(glenn);
            db.set(neal);

            db.commit();
            
            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0));
            while (brians.hasNext())
                System.out.println(brians.next());
                
            Person brian2 = new Person("Brian", "Goetz", 39);
                db.set(brian2);
                db.commit();

            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0));
            while (brians.hasNext())
                System.out.println(brians.next());
        }
        finally
        {
            if (db != null)
                db.close();
        }
    }
}

                // ... as before
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");
            
            ...

            // We want to add Brian Goetz to the database; is he already there?
            if (db.get(new Person("Brian", "Goetz", 0).hasNext() == false)
            {
                // Nope, no Brian Goetz here, go ahead and add him
                db.set(new Person("Brian", "Goetz", 39));
                db.commit();
            }
        }

                // ... as before
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");
            
            ...

            // Happy Birthday, David Geary!
            if ((ObjectSet set = db.get(new Person("David", "Geary", 0))).hasNext())
            {
                Person davidG = (Person)set.next();
                davidG.setAge(davidG.getAge() + 1);
                db.set(davidG);
                db.commit();
            }
            else
                throw new MissingPersonsException(
                    "David Geary doesn't seem to be in the database");
        }

                import java.lang.reflect.*;
import com.db4o.*;

public class Util
{
    public static boolean identitySearch(ObjectContainer db, Class type,
        String[] fields, Object[] values)
            throws InstantiationException, IllegalAccessException,
                NoSuchFieldException
    {
            // Create an instance of our type
            Object template = type.newInstance();
            
            // Populate its fields with the passed-in template values
            for (int i=0; i            {
                Field f = type.getDeclaredField(fields[i]);
                if (f == null)
                    throw new IllegalArgumentException("Field " + fields[i] + 
                        " not found on type " + type);
                if (Modifier.isStatic(f.getModifiers()))
                    throw new IllegalArgumentException("Field " + fields[i] + 
                        " is a static field and cannot be used in a QBE query");
                f.setAccessible(true);
                f.set(template, values[i]);
            }
            
            // Do the query
            ObjectSet set = db.get(template);
            if (set.hasNext())
                return true;
            else
                return false;
    }
}

                // Is Brian already in the database?
if (Util.identitySearch(
    db, Person.class, {"firstName", "lastName"}, {"Brian", "Goetz"}) == false)
{
    db.set(new Person("Brian", "Goetz", 39));
    db.commit();
}

                public class Person
{
    // ... as before
    
    public static boolean exists(ObjectContainer db, Person instance)
    {
        return (Util.identitySearch(db, Person.class,
            {"firstName", "lastName"},
            {instance.getFirstName(), instance.getLastName()});
    }
}

                Query q = new Query();
q.setClass(Person.class);
q.setPredicate(new Predicate(
    new And(
        new Equals(new Field("firstName"), "David"),
        new GreaterThan(new Field("age"), 21)
    )));
q.Execute();

                SELECT p FROM Person
WHERE p.firstName = "David" AND p.age > 21

                // ... as before
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");
            
            ...

            // Who wants to get a beer?
            List drinkers = db.query(new Predicate() {
                public boolean match(Person candidate) {
                    return person.getAge() > 21;
                }
            }
            for (Person drinker : drinkers)
                System.out.println("Here's your beer, " + person.getFirstName());
        }

                // ... as before
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");
            
            db.ext().configure().diagnostic().addListener(new DiagnosticListener() {
                public void onDiagnostic(Diagnostic d) {
                    if (d instanceof NativeQueryNotOptimized)
                    {
                        // could display information here, but for simplicity
                        // let's just fail loudly
                        throw new RuntimeException("Native query failed optimization!");
                    }
                }
            });
        }

                package com.tedneward.model;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, int age)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }

    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "age = " + age + 
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private int age;
}

                import java.io.*;
import java.lang.reflect.*;
import com.db4o.*;
import com.tedneward.model.*;

// Version 1
public class BuildV1
{
    public static void main(String[] args)
        throws Exception
    {
        new File(".", "persons.data").delete();
        
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person brianG = new Person("Brian", "Goetz", 39);
            Person jason = new Person("Jason", "Hunter", 35);
            Person brianS = new Person("Brian", "Sletten", 38);
            Person david = new Person("David", "Geary", 55);
            Person glenn = new Person("Glenn", "Vanderberg", 40);
            Person neal = new Person("Neal", "Ford", 39);
            Person clinton = new Person("Clinton", "Begin", 19);
            
            db.set(brianG);
            db.set(jason);
            db.set(brianS);
            db.set(david);
            db.set(glenn);
            db.set(neal);
            db.set(clinton);

            db.commit();
            
            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0));
            while (brians.hasNext())
                System.out.println(brians.next());            
        }
        finally
        {
            if (db != null)
                db.close(); 
        }
    }
}

                package com.tedneward.model;

public enum Mood
{
    HAPPY, CONTENT, BLAH, CRANKY, DEPRESSED, PSYCHOTIC, WRITING_AN_ARTICLE
}

                package com.tedneward.model;

// Person v2
public class Person
{
    // ... as before, with appropriate modifications to public constructor and
    // toString() method
    
    public Mood getMood() { return mood; }
    public void setMood(Mood value) { mood = value; }

    private Mood mood;
}

                import com.db4o.*;
import com.tedneward.model.*;

// Version 2
public class ReadV2
{
    public static void main(String[] args)
        throws Exception
    {
        // Note the absence of the File.delete() call
        
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            // Find all the Brians
            ObjectSet brians = db.get(new Person("Brian", null, 0, null));
            while (brians.hasNext())
                System.out.println(brians.next());            
        }
        finally
        {
            if (db != null)
                db.close(); 
        }
    }
}

                
[Person: firstName = Brian lastName = Sletten age = 38 mood = null]
[Person: firstName = Brian lastName = Goetz age = 39 mood = null]

                import com.db4o.*;
import com.tedneward.model.*;

// Version 2
public class BuildV2
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            // Find all the Persons, and give them moods
            ObjectSet people = db.get(Person.class);
            while (people.hasNext())
            {
                Person person = (Person)people.next();
                
                System.out.print("Setting " + person.getFirstName() + "'s mood ");
                int moodVal = (int)(Math.random() * Mood.values().length);
                person.setMood(Mood.values()[moodVal]);
                System.out.println("to " + person.getMood());
                db.set(person);
            }
            
            db.commit();            
        }
        finally
        {
            if (db != null)
                db.close(); 
        }
    }
}

                Setting Brian's mood to BLAH
Setting David's mood to WRITING_AN_ARTICLE
Setting Brian's mood to CONTENT
Setting Jason's mood to PSYCHOTIC
Setting Glenn's mood to BLAH
Setting Neal's mood to HAPPY
Setting Clinton's mood to DEPRESSED

                
[Person: firstName = Brian lastName = Sletten age = 38]
[Person: firstName = Brian lastName = Goetz age = 39]

                import com.db4o.*;
import com.db4o.config.*;

// ...

Db4o.configure().objectClass("com.tedneward.model.Person")
    .rename("com.tedneward.persons.model.Individual");

                import com.db4o.config.*;

// ...

TypeAlias fromPersonToIndividual = 
    new TypeAlias("com.tedneward.model.Person", "com.tedneward.persons.model.Individual");
Db4o.configure().addAlias(fromPersonToIndividual);

                
package com.tedneward.model;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, int age, Mood mood)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
        this.mood = mood;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }
    
    public Mood getMood() { return mood; }
    public void setMood(Mood value) { mood = value; }

    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "age = " + age + " " + 
            "mood = " + mood +
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private int age;
    private Mood mood;
}

                
package com.tedneward.model;
public class Person {
    // . . .

    public Person getSpouse() { return spouse; }
    public void setSpouse(Person value) { 
        // A few business rules
        if (spouse != null)
            throw new IllegalArgumentException("Already married!");
        
        if (value.getSpouse() != null && value.getSpouse() != this)
            throw new IllegalArgumentException("Already married!");
            
        spouse = value; 
        
        // Highly sexist business rule
        if (gender == Gender.FEMALE)
            this.setLastName(value.getLastName());

        // Make marriage reflexive, if it's not already set that way
        if (value.getSpouse() != this)
            value.setSpouse(this);
    }
    
    private Person spouse;    
}

                
import java.util.*;
import com.db4o.*;
import com.db4o.query.*;
import com.tedneward.model.*;

public class App
{
    public static void main(String[] args)
        throws Exception
    {
        ObjectContainer db = null;
        try
        {
            db = Db4o.openFile("persons.data");

            Person ben = new Person("Ben", "Galbraith", 
                Gender.MALE, 29, Mood.HAPPY);
            Person jess = new Person("Jessica", "Smith", 
                Gender.FEMALE, 29, Mood.HAPPY);
            
            ben.setSpouse(jess);
            
            System.out.println(ben);
            System.out.println(jess);
            
            db.set(ben);
            
            db.commit();
            
            List maleGalbraiths = 
                db.query(new Predicate() {
                    public boolean match(Person candidate) {
                        return candidate.getLastName().equals("Galbraith") &&
                                candidate.getGender().equals(Gender.MALE);
                    }
                });
            for (Person p : maleGalbraiths)
            {
                System.out.println("Found " + p);
            }
        }
        finally
        {
            if (db != null)
                db.close(); 
        }
    }
}

                
import java.io.*;
import java.util.*;
import com.db4o.*;
import com.db4o.query.*;
import com.tedneward.model.*;

import org.junit.Before;
import org.junit.After; 
import org.junit.Ignore; 
import org.junit.Test; 
import static org.junit.Assert.*;

public class StructuredObjectsTest
{
    ObjectContainer db;

    @Before public void prepareDatabase()
    {
        db = Db4o.openFile("persons.data");

        Person ben = new Person("Ben", "Galbraith", 
            Gender.MALE, 29, Mood.HAPPY);
        Person jess = new Person("Jessica", "Smith", 
            Gender.FEMALE, 29, Mood.HAPPY);
    
        ben.setSpouse(jess);
    
        db.set(ben);
    
        db.commit();
    }
    
    @After public void deleteDatabase()
    {
        db.close();
        new File("persons.data").delete();
    }


    @Test public void testSimpleRetrieval()
    {
        List maleGalbraiths = 
            db.query(new Predicate() {
                public boolean match(Person candidate) {
                    return candidate.getLastName().equals("Galbraith") &&
                            candidate.getGender().equals(Gender.MALE);
                }
            });
            
        // Should only have one in the returned set
        assertEquals(maleGalbraiths.size(), 1);

        // (Shouldn't display to the console in a unit test, but this is an
        // exploration test, not a real unit test)
        for (Person p : maleGalbraiths)
        {
            System.out.println("Found " + p);
        }
    }
}

                
// See ObjectClass for more info
Configuration config = Db4o.configure();
ObjectClass oc = config.objectClass("com.tedneward.model.Person");
oc.minimumActivationDepth(10);

                
@Test public void testDependentUpdate()
{
    List maleGalbraiths = 
        db.query(new Predicate() {
            public boolean match(Person candidate) {
                return candidate.getLastName().equals("Galbraith") &&
                        candidate.getGender().equals(Gender.MALE);
            }
        });
        
    Person ben = maleGalbraiths.get(0);
        
    // Happy birthday, Jessica!
    ben.getSpouse().setAge(ben.getSpouse().getAge() + 1);

    // We only have a reference to Ben, so store that and commit
    db.set(ben);
    db.commit();

    // Find Jess, make sure she's 30
    Person jess = (Person)db.get(
            new Person("Jessica", "Galbraith", null, 0, null)).next();
    assertTrue(jess.getAge() == 30);
}

                
@Test(expected=AssertionError.class)
public void testDependentUpdate()
{
    List maleGalbraiths = 
        db.query(new Predicate() {
            public boolean match(Person candidate) {
                return candidate.getLastName().equals("Galbraith") &&
                        candidate.getGender().equals(Gender.MALE);
            }
        });
            
    Person ben = maleGalbraiths.get(0);
    assertTrue(ben.getSpouse().getAge() == 29);
    
    // Happy Birthday, Jessica!
    ben.getSpouse().setAge(ben.getSpouse().getAge() + 1);

    // We only have a reference to Ben, so store that and commit
    db.set(ben);
    db.commit();
        
    // Close the ObjectContainer, then re-open it
    db.close();
    db = Db4o.openFile("persons.data");

    // Find Jess, make sure she's 30
    Person jess = (Person)db.get(
            new Person("Jessica", "Galbraith", null, 0, null)).next();
    assertTrue(jess.getAge() == 30);
}

                
@Test
public void testWorkingDependentUpdate()
{
    // the cascadeOnUpdate() call must be done while the ObjectContainer 
    // isn't open, so close() it, setCascadeOnUpdate, then open() it again
    db.close();
    Db4o.configure().objectClass(Person.class).cascadeOnUpdate(true);
    db = Db4o.openFile("persons.data");

    List maleGalbraiths = 
        db.query(new Predicate() {
            public boolean match(Person candidate) {
                return candidate.getLastName().equals("Galbraith") &&
                        candidate.getGender().equals(Gender.MALE);
            }
        });
           
    Person ben = maleGalbraiths.get(0);
    assertTrue(ben.getSpouse().getAge() == 29);
        
    // Happy Birthday, Jessica!
    ben.getSpouse().setAge(ben.getSpouse().getAge() + 1);

    // We only have a reference to Ben, so store that and commit
    db.set(ben);
    db.commit();
        
    // Close the ObjectContainer, then re-open it
    db.close();
        
    db = Db4o.openFile("persons.data");

    // Find Jess, make sure she's 30
    Person jess = (Person)db.get(
            new Person("Jessica", "Galbraith", null, 0, null)).next();
    assertTrue(jess.getAge() == 30);
}

                
@Test
public void simpleDeletion()
{
  Person ben = (Person)db.get(new Person("Ben", "Galbraith", null, 0, null)).next();
  db.delete(ben);
        
  Person jess = (Person)db.get(new Person("Jessica", "Galbraith", null, 0, null)).next();
  assertNotNull(jess);
}

                
@Test
public void cascadingDeletion()
{
    // the cascadeOnUpdate() call must be done while the ObjectContainer 
    // isn't open, so close() it, setCascadeOnUpdate, then open() it again
    db.close();
    Db4o.configure().objectClass(Person.class).cascadeOnDelete(true);
    db = Db4o.openFile("persons.data");

    Person ben = 
        (Person)db.get(new Person("Ben", "Galbraith", null, 0, null)).next();
    db.delete(ben);
        
    ObjectSet results = 
        db.get(new Person("Jessica", "Galbraith", null, 0, null));
    assertFalse(results.hasNext());
}

                
package com.tedneward.model;

public class Address
{
    public Address()
    {
    }
    
    public Address(String street, String city, String state, String zip)
    {
        this.street = street; this.city = city; 
        this.state = state; this.zip = zip;
    }
    
    public String toString()
    {
        return "[Address: " + 
                "street=" + street + " " +
                "city=" + city + " " +
                "state=" + state + " " +
                "zip=" + zip + "]";
    }
    
    public int hashCode()
    {
        return street.hashCode() & city.hashCode() &
            state.hashCode() & zip.hashCode();
    }
    
    public boolean equals(Object obj)
    {
        if (obj == this)
            return this;
            
        if (obj instanceof Address)
        {
            Address rhs = (Address)obj;
            
            return (this.street.equals(rhs.street) &&
                this.city.equals(rhs.city) &&
                this.state.equals(rhs.state) &&
                this.zip.equals(rhs.zip));
        }
        else
            return false;
    }
    
    public String getStreet() { return this.street; }
    public void setStreet(String value) { this.street = value; }
    
    public String getCity() { return this.city; }
    public void setCity(String value) { this.city = value; }
    
    public String getState() { return this.state; }
    public void setState(String value) { this.state = value; }
    
    public String getZip() { return this.zip; }
    public void setZip(String value) { this.zip = value; }
    
    private String street;
    private String city;
    private String state;
    private String zip;
}

                
package com.tedneward.model;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, Gender gender, int age, Mood mood)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.gender = gender;
        this.age = age;
        this.mood = mood;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }

    public Gender getGender() { return gender; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }
    
    public Mood getMood() { return mood; }
    public void setMood(Mood value) { mood = value; }

    public Person getSpouse() { return spouse; }
    public void setSpouse(Person value) { 
        // A few business rules
        if (spouse != null)
            throw new IllegalArgumentException("Already married!");
        
        if (value.getSpouse() != null && value.getSpouse() != this)
            throw new IllegalArgumentException("Already married!");
            
        spouse = value; 
        
        // Highly sexist business rule
        if (gender == Gender.FEMALE)
            this.setLastName(value.getLastName());

        // Make marriage reflexive, if it's not already set that way
        if (value.getSpouse() != this)
            value.setSpouse(this);
    }

    public Address getHomeAddress() { return addresses[0]; }
    public void setHomeAddress(Address value) { addresses[0] = value; }

    public Address getWorkAddress() { return addresses[1]; }
    public void setWorkAddress(Address value) { addresses[1] = value; }

    public Address getVacationAddress() { return addresses[2]; }
    public void setVacationAddress(Address value) { addresses[2] = value; }

    public Iterator getChildren() { return children.iterator(); }
    public Person haveBaby(String name, Gender gender) {
        // Business rule
        if (this.gender.equals(Gender.MALE))
            throw new UnsupportedOperationException("Biological impossibility!");
        
        // Another highly objectionable business rule
        if (getSpouse() == null)
            throw new UnsupportedOperationException("Ethical impossibility!");

        // Welcome to the world, little one!
        Person child = new Person(name, this.lastName, gender, 0, Mood.CRANKY);
            // Well, wouldn't YOU be cranky if you'd just been pushed out of
            // a nice warm place?!?

        // These are your parents...            
        child.father = this.getSpouse();
        child.mother = this;
        
        // ... and you're their new baby.
        // (Everybody say "Awwww....")
        children.add(child);
        this.getSpouse().children.add(child);

        return child;
    }
    
    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "gender = " + gender + " " +
            "age = " + age + " " + 
            "mood = " + mood + " " +
            (spouse != null ? "spouse = " + spouse.getFirstName() + " " : "") +
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.gender.equals(other.gender) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private Gender gender;
    private int age;
    private Mood mood;
    private Person spouse;
    private Address[] addresses = new Address[3];
    private List children = new ArrayList();
    private Person mother;
    private Person father;
}

                    
@Test public void testTheModel()
    {
        Person bruce = new Person("Bruce", "Tate", 
            Gender.MALE, 29, Mood.HAPPY);
        Person maggie = new Person("Maggie", "Tate", 
            Gender.FEMALE, 29, Mood.HAPPY);
        bruce.setSpouse(maggie);

        Person kayla = maggie.haveBaby("Kayla", Gender.FEMALE);

        Person julia = maggie.haveBaby("Julia", Gender.FEMALE);
        
        assertTrue(julia.getFather() == bruce);
        assertTrue(kayla.getFather() == bruce);
        assertTrue(julia.getMother() == maggie);
        assertTrue(kayla.getMother() == maggie);
        
        int n = 0;
        for (Iterator kids = bruce.getChildren(); kids.hasNext(); )
        {
            Person child = kids.next();
            
            if (n == 0) assertTrue(child == kayla);
            if (n == 1) assertTrue(child == julia);
            
            n++;
        }
    }

                    
@Before public void prepareDatabase()
    {
        db = Db4o.openFile("persons.data");

        Person bruce = new Person("Bruce", "Tate", 
            Gender.MALE, 29, Mood.HAPPY);
        Person maggie = new Person("Maggie", "Tate", 
            Gender.FEMALE, 29, Mood.HAPPY);
        bruce.setSpouse(maggie);
        
        bruce.setHomeAddress(
            new Address("5 Maple Drive", "Austin",
                "TX", "12345"));
        bruce.setWorkAddress(
            new Address("5 Maple Drive", "Austin",
                "TX", "12345"));
        bruce.setVacationAddress(
            new Address("10 Wanahokalugi Way", "Oahu",
                "HA", "11223"));

        Person kayla = maggie.haveBaby("Kayla", Gender.FEMALE);
        kayla.setAge(8);

        Person julia = maggie.haveBaby("Julia", Gender.FEMALE);
        julia.setAge(6);
    
        db.set(bruce);
    
        db.commit();
    }

                    
@Test public void testTheStorageOfAddresses()
    {
        List maleTates = 
            db.query(new Predicate() {
                public boolean match(Person candidate) {
                    return candidate.getLastName().equals("Tate") &&
                            candidate.getGender().equals(Gender.MALE);
                }
            });
        Person bruce = maleTates.get(0);

        Address homeAndWork = 
            new Address("5 Maple Drive", "Austin",
                "TX", "12345");
        Address vacation =
            new Address("10 Wanahokalugi Way", "Oahu",
                "HA", "11223");
                
        assertTrue(bruce.getHomeAddress().equals(homeAndWork));
        assertTrue(bruce.getWorkAddress().equals(homeAndWork));
        assertTrue(bruce.getVacationAddress().equals(vacation));
    }

    @Test public void testTheStorageOfChildren() 
    { 
        List maleTates = 
            db.query(new Predicate() {
                public boolean match(Person candidate) {
                    return candidate.getLastName().equals("Tate") &&
                            candidate.getGender().equals(Gender.MALE);
                }
            });
        Person bruce = maleTates.get(0);
        
        int n = 0;
        for (Iterator children = bruce.getChildren(); 
             children.hasNext();
            )
        {
            Person child = children.next();
            
            System.out.println(child);
            
            if (n==0) assertTrue(child.getFirstName().equals("Kayla"));
            if (n==1) assertTrue(child.getFirstName().equals("Julia"));
            
            n++;
        }
    }

                    
@Test public void findTheGirls()
    {
        List girls = 
            db.query(new Predicate() {
                public boolean match(Person candidate) {
                    return candidate.getGender().equals(Gender.FEMALE);
                }
            });
        boolean maggieFound = false;
        boolean kaylaFound = false;
        boolean juliaFound = false;
        for (Person p : girls)
        {
            if (p.getFirstName().equals("Maggie"))
                maggieFound = true;
            if (p.getFirstName().equals("Kayla"))
                kaylaFound = true;
            if (p.getFirstName().equals("Julia"))
                juliaFound = true;
        }
        
        assertTrue(maggieFound);
        assertTrue(kaylaFound);
        assertTrue(juliaFound);
    }

                    
@Test public void findJuliaAndHerMommy()
    {
        Person maggie = (Person) db.get(
                new Person("Maggie", "Tate", Gender.FEMALE, 0, null)).next();
        Person julia = (Person) db.get(
                new Person("Julia", "Tate", Gender.FEMALE, 0, null)).next();

        assertTrue(julia.getMother() == maggie);
    }

                    
@Test public void kaylaHasABirthday()
    {
        Person maggie = (Person) db.get(
                new Person("Maggie", "Tate", Gender.FEMALE, 0, null)).next();
        Person kayla = (Person) db.get(
                new Person("Kayla", "Tate", Gender.FEMALE, 0, null)).next();

        kayla.setAge(kayla.getAge() + 1);
        int kaylasNewAge = kayla.getAge();
        
        db.set(maggie);

        db.close();

        db = Db4o.openFile("persons.data");

        kayla = (Person) db.get(
                new Person("Kayla", "Tate", Gender.FEMALE, 0, null)).next();
        assert(kayla.getAge() == kaylasNewAge);
    }
    

                
package com.tedneward.model;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;

public class Person
{
    public Person()
    { }
    public Person(String firstName, String lastName, Gender gender, int age, Mood mood)
    {
        this.firstName = firstName;
        this.lastName = lastName;
        this.gender = gender;
        this.age = age;
        this.mood = mood;
    }
    
    public String getFirstName() { return firstName; }
    public void setFirstName(String value) { firstName = value; }
    
    public String getLastName() { return lastName; }
    public void setLastName(String value) { lastName = value; }

    public Gender getGender() { return gender; }
    
    public int getAge() { return age; }
    public void setAge(int value) { age = value; }
    
    public Mood getMood() { return mood; }
    public void setMood(Mood value) { mood = value; }

    public Person getSpouse() { return spouse; }
    public void setSpouse(Person value) { 
        // A few business rules
        if (spouse != null)
            throw new IllegalArgumentException("Already married!");
        
        if (value.getSpouse() != null && value.getSpouse() != this)
            throw new IllegalArgumentException("Already married!");
            
        spouse = value; 
        
        // Highly sexist business rule
        if (gender == Gender.FEMALE)
            this.setLastName(value.getLastName());

        // Make marriage reflexive, if it's not already set that way
        if (value.getSpouse() != this)
            value.setSpouse(this);
    }

    public Address getHomeAddress() { return addresses[0]; }
    public void setHomeAddress(Address value) { addresses[0] = value; }

    public Address getWorkAddress() { return addresses[1]; }
    public void setWorkAddress(Address value) { addresses[1] = value; }

    public Address getVacationAddress() { return addresses[2]; }
    public void setVacationAddress(Address value) { addresses[2] = value; }

    public Iterator getChildren() { return children.iterator(); }
    public Person haveBaby(String name, Gender gender) {
        // Business rule
        if (this.gender.equals(Gender.MALE))
            throw new UnsupportedOperationException("Biological impossibility!");
        
        // Another highly objectionable business rule
        if (getSpouse() == null)
            throw new UnsupportedOperationException("Ethical impossibility!");

        // Welcome to the world, little one!
        Person child = new Person(name, this.lastName, gender, 0, Mood.CRANKY);
            // Well, wouldn't YOU be cranky if you'd just been pushed out of
            // a nice warm place?!?

        // These are your parents...            
        child.father = this.getSpouse();
        child.mother = this;
        
        // ... and you're their new baby.
        // (Everybody say "Awwww....")
        children.add(child);
        this.getSpouse().children.add(child);

        return child;
    }
    
    public Person getFather() { return this.father; }
    public Person getMother() { return this.mother; }
    
    public String toString()
    {
        return 
            "[Person: " +
            "firstName = " + firstName + " " +
            "lastName = " + lastName + " " +
            "gender = " + gender + " " +
            "age = " + age + " " + 
            "mood = " + mood + " " +
            (spouse != null ? "spouse = " + spouse.getFirstName() + " " : "") +
            "]";
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == this)
            return true;
        
        if (!(rhs instanceof Person))
            return false;
        
        Person other = (Person)rhs;
        return (this.firstName.equals(other.firstName) &&
                this.lastName.equals(other.lastName) &&
                this.gender.equals(other.gender) &&
                this.age == other.age);
    }
    
    private String firstName;
    private String lastName;
    private Gender gender;
    private int age;
    private Mood mood;
    private Person spouse;
    private Address[] addresses = new Address[3];
    private List children = new ArrayList();
    private Person mother;
    private Person father;
}

                
package com.tedneward.model;

public class Employee extends Person
{
    public Employee()
    { }
    public Employee(String firstName, String lastName, String title,
                     Gender gender, int age, Mood mood)
    {
        super(firstName, lastName, gender, age, mood);
        
        this.title = title;
    }

    public String getTitle() { return title; }
    public void setTitle(String value) { title = value; }
    
    public String toString()
    {
        return "[Employee: " + getFirstName() + " " + getLastName() + " " +
            "(" + getTitle() + ")]";
    }
    
    private String title;
}
    

                
    @Before public void prepareDatabase()
    {
        db = Db4o.openFile("persons.data");

        // The Newards
        Employee ted = new Employee("Ted", "Neward", "President and CEO",
            Gender.MALE, 36, Mood.HAPPY);
        Person charlotte = new Person("Charlotte", "Neward",
            Gender.FEMALE, 35, Mood.HAPPY);
        ted.setSpouse(charlotte);
        Person michael = charlotte.haveBaby("Michael", Gender.MALE);
        michael.setAge(14);
        Person matthew = charlotte.haveBaby("Matthew", Gender.MALE);
        matthew.setAge(8);
        Address tedsHomeOffice = 
            new Address("12 Redmond Rd", "Redmond", "WA", "98053");
        ted.setHomeAddress(tedsHomeOffice);
        ted.setWorkAddress(tedsHomeOffice);
        ted.setVacationAddress(
            new Address("10 Wannahokalugi Way", "Oahu", "HA", "11223"));
        db.set(ted);
        
        // The Tates
        Employee bruce = new Employee("Bruce", "Tate", "Chief Technical Officer", 
            Gender.MALE, 29, Mood.HAPPY);
        Person maggie = new Person("Maggie", "Tate", 
            Gender.FEMALE, 29, Mood.HAPPY);
        bruce.setSpouse(maggie);
        Person kayla = maggie.haveBaby("Kayla", Gender.FEMALE);
        Person julia = maggie.haveBaby("Julia", Gender.FEMALE);
        bruce.setHomeAddress(
            new Address("5 Maple Drive", "Austin",
                "TX", "12345"));
        bruce.setWorkAddress(
            new Address("5701 Downtown St", "Austin",
                "TX", "12345"));
        // Ted and Bruce both use the same timeshare, apparently
        bruce.setVacationAddress(
            new Address("10 Wanahokalugi Way", "Oahu",
                "HA", "11223"));
        db.set(bruce);
        
        // The Fords
        Employee neal = new Employee("Neal", "Ford", "Meme Wrangler",
            Gender.MALE, 29, Mood.HAPPY);
        Person candi = new Person("Candi", "Ford",
            Gender.FEMALE, 29, Mood.HAPPY);
        neal.setSpouse(candi);
        neal.setHomeAddress(
            new Address("22 Gritsngravy Way", "Atlanta", "GA", "32145"));
        // Neal is the roving architect
        neal.setWorkAddress(null);
        db.set(neal);
        
        // The Slettens
        Employee brians = new Employee("Brian", "Sletten", "Bosatsu Master",
            Gender.MALE, 29, Mood.HAPPY);
        Person kristen = new Person("Kristen", "Sletten",
            Gender.FEMALE, 29, Mood.HAPPY);
        brians.setSpouse(kristen);
        brians.setHomeAddress(
            new Address("57 Classified Drive", "Fairfax", "VA", "55555"));
        brians.setWorkAddress(
            new Address("1 CIAWasNeverHere Street", "Fairfax", "VA", "55555"));
        db.set(brians);
        
        // The Galbraiths
        Employee ben = new Employee("Ben", "Galbraith", "Chief UI Director",
            Gender.MALE, 29, Mood.HAPPY);
        Person jessica = new Person("Jessica", "Galbraith",
            Gender.FEMALE, 29, Mood.HAPPY);
        ben.setSpouse(jessica);
        ben.setHomeAddress(
            new Address(
                "5500 North 2700 East Rd", "Salt Lake City", 
                "UT", "12121"));
        ben.setWorkAddress(
            new Address(
                "5600 North 2700 East Rd", "Salt Lake City",
                "UT", "12121"));
        ben.setVacationAddress(
            new Address(
                "2700 East 5500 North Rd", "Salt Lake City",
                "UT", "12121"));
            // Ben really needs to get out more
        db.set(ben);
        
        db.commit();
    }
    

                
@Test public void testSimpleInheritanceQueries()
{
    ObjectSet employees = db.get(Employee.class);
    while (employees.hasNext())
        System.out.println("Found " + employees.next());
}
    

                
@Test public void testSimpleNonEmployeeQuery()
{
    ObjectSet persons = db.get(Person.class);
    while (persons.hasNext())
        System.out.println("Found " + persons.next());
}
    

                
.Found [Employee: Ted Neward (President and CEO)]
Found [Person: firstName = Charlotte lastName = Neward gender = FEMALE age = 35
mood = HAPPY spouse = Ted ]
Found [Person: firstName = Michael lastName = Neward gender = MALE age = 14 mood
 = CRANKY ]
Found [Person: firstName = Matthew lastName = Neward gender = MALE age = 8 mood
= CRANKY ]
Found [Employee: Bruce Tate (Chief Technical Officer)]
Found [Person: firstName = Maggie lastName = Tate gender = FEMALE age = 29 mood
= HAPPY spouse = Bruce ]
Found [Person: firstName = Kayla lastName = Tate gender = FEMALE age = 0 mood =
CRANKY ]
Found [Person: firstName = Julia lastName = Tate gender = FEMALE age = 0 mood =
CRANKY ]
Found [Employee: Neal Ford (Meme Wrangler)]
Found [Person: firstName = Candi lastName = Ford gender = FEMALE age = 29 mood =
 HAPPY spouse = Neal ]
Found [Employee: Brian Sletten (Bosatsu Master)]
Found [Person: firstName = Kristen lastName = Sletten gender = FEMALE age = 29 m
ood = HAPPY spouse = Brian ]
Found [Employee: Ben Galbraith (Chief UI Director)]
Found [Person: firstName = Jessica lastName = Galbraith gender = FEMALE age = 29
 mood = HAPPY spouse = Ben ]

                
@Test public void testNativeQuery()
{
    List spouses =
        db.query(new Predicate() {
            public boolean match(Person candidate) {
                return (candidate.getSpouse() instanceof Employee);
            }
        });
    for (Person spouse : spouses)
        System.out.println(spouse);
}
    

                
@Test public void testEmployeeNativeQuery()
{
    List spouses =
        db.query(new Predicate() {
            public boolean match(Person candidate) {
                return (candidate.getSpouse() instanceof Employee);
            }
        });
    for (Person spouse : spouses)
        System.out.println(spouse);
}
    

                
package com.tedneward.model;

public interface Employable
{
    public boolean willYouWorkForUs();
}

                
@Test public void testEmployableQuery()
{
    List potentialEmployees =
        db.query(new Predicate() {
            public boolean match(Employable candidate) {
                return (candidate.willYouWorkForUs());
            }
        });
    for (Employable e : potentialEmployees)
        System.out.println("Eureka! " + e + " has said they'll work for us!");
}