	Emerging Technology Fall Semester, 2004 Mapping Collections
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CS 683 Emerging Technologies Fall Semester, 2004 Doc 32 Mapping Collections

Bag

Tables

Glorp Dictionary Mapping

Classes

Copyright ©, All rights reserved. 2004 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA. OpenContent ( http://www.opencontent.org/opl.shtml) license defines the copyright on this document

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 2

References

Hibernate Reference 2.1.6

Online html version http://www.hibernate.org/hib_docs/reference/en/html/

Other versions (including Chinese) at: http://www.hibernate.org/5.html

Glorp Tutorial, Whitney

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 3

Mapping Collections

Types of Collections

Set
Bag
List
Maps
Arrays

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 4

Bag

Allows repeats of elements

Order is not important

Hibernate uses List to implement a bag

Order of elements added to the database is not preserved

Example is the Person-EmailAddresses of doc 31

Tables

People

id	first_name	last_name
1	Roger	Whitney
2	Leland	Beck

Email_Addresses

id	user_name	host	person_id
1	beck	cs.sdsu.edu	2
2	whitney	cs.sdsu.edu	1
3	whitney	rohan.sdsu.edu	1

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 5

People.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
   
<hibernate-mapping package="cs683">
   <class
      name="Person"
      table="people">
      <id
         name="id"
         type="long"
         column="id">
         <generator class="increment"/>
      </id>
   
      <bag name="addresses" inverse="false" cascade="all" 
            table="EMAIL_ADDRESSES">
         <key  column="person_id"/>
         <one-to-many class="cs683.EmailAddress" />
      </bag>
   
      <property
         name="lastName"
         column="last_name"
         type="string"
         not-null="false"
         length="50"/>
      <property
         name="firstName"
         column="first_name"
         type="string"
         not-null="false"
         length="50"/>
   </class>
</hibernate-mapping>

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 6

People Class

package cs683;
import java.util.*;
   
public class Person {
   String firstName;
   String lastName;
   List addresses =  new ArrayList();;
   long id;
   
   public Person () { super(); }
   
   public Person(String first, String last) {
      firstName = first;
      lastName = last;
   }
   
   public List getAddresses() {   return addresses; }
   public void setAddresses(List addresses) { this.addresses = addresses; }
   
   public void addAddress(EmailAddress newAddress) {
      addresses.add( newAddress);
      newAddress.setOwner(this);
   }
   
   public String getLastName() { return lastName; }
   public String getFirstName() { return firstName; }
   
   public void setFirstName( String name) { firstName = name; }
   public void setLastName( String name) {    lastName = name; }
   
   public long getId() {   return id; }
   public void setId(long l) {    id = l; }
   
   public String toString() { return firstName + " " + lastName + id; }
}

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 7

List

ArrayList & Vector are lists

Order of elements in the list are preserved

Tables

People

id	first_name	last_name
1	Roger	Whitney
2	Leland	Beck
3	Carl	Eckberg

Email_Addresses

id	user_name	host	person_id	Position
1	beck	cs.sdsu.edu	2	0
2	whitney	cs.sdsu.edu	1	0
3	whitney	rohan.sdsu.edu	1	1

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 8

People.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
   
<hibernate-mapping package="cs683">
   <class
      name="Person"
      table="people"
   >
      <id
         name="id"
         type="long"
         column="id"
      >
         <generator class="increment"/>
      </id>
   
      <list name="addresses" inverse="false" cascade="all" 
         table="EMAIL_ADDRESSES">
         <key  column="person_id"/>
         <index column="position">      
         </index>
         <one-to-many class="cs683.EmailAddress" />
      </list>
   
      properties same as last example
   
   </class>
</hibernate-mapping>

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 9

Person

package cs683;
   
import java.util.*;
   
public class Person {
   String firstName;
   String lastName;
   List addresses =  new ArrayList();
   long id;
   
   public Person () {
      super();
   }
   
   public Person(String first, String last) {
      firstName = first;
      lastName = last;
   }
   
   public List getAddresses() {
      return addresses;
   }
   public void setAddresses(List addresses) {
      this.addresses = addresses;
   }
   
   public void addAddress(EmailAddress newAddress) {
      addresses.add( newAddress);
      newAddress.setOwner(this);
   }

rest same as last example

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 10

Arrays

Java arrays are not Collection classes

Tables

People

id	first_name	last_name
1	Roger	Whitney
2	Leland	Beck

Email_Addresses

id	user_name	host	person_id	Position
1	beck	cs.sdsu.edu	2	0
2	whitney	cs.sdsu.edu	1	0
3	whitney	rohan.sdsu.edu	1	1

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 11

People.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
   
<hibernate-mapping package="cs683">
   <class
      name="Person"
      table="people">
      <id
         name="id"
         type="long"
         column="id" >
         <generator class="increment"/>
      </id>
   
      <array name="addresses" inverse="false" cascade="all" 
            table="EMAIL_ADDRESSES">
         <key  column="person_id"/>
         <index column="position" />
         <one-to-many class="cs683.EmailAddress" />
      </array>

Rest is same as before

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 12

Person

package cs683;
   
public class Person {
   String firstName;
   String lastName;
   EmailAddress[] addresses =  new EmailAddress[10];
   int endOfList;
   long id;
   
   public Person () {super(); }
   
   public Person(String first, String last) {
      firstName = first;
      lastName = last;
   }
   
   public EmailAddress[] getAddresses() {
      return addresses;
   }
   public void setAddresses(EmailAddress[] addresses) {
      this.addresses = addresses;
   }
   
   public void addAddress(EmailAddress newAddress) {
      addresses[endOfList++]= newAddress;
      newAddress.setOwner(this);
   }

rest is as previous examples

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 13

Sorted Collection

TreeMap and TreeSet are examples of sorted collections in Java

Since the collection orders the elements one does not need extra columns in the database

Tables

People

id	first_name	last_name
1	Roger	Whitney
2	Leland	Beck

Email_Addresses

id	user_name	host	person_id
1	beck	cs.sdsu.edu	2
2	whitney	cs.sdsu.edu	1
3	whitney	rohan.sdsu.edu	1

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 14

People.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
   
<hibernate-mapping package="cs683">
   <class
      name="Person"
      table="people"
   >
      <id
         name="id"
         type="long"
         column="id"
      >
         <generator class="increment"/>
      </id>
   
      <set name="addresses" inverse="false" cascade="all" 
            table="EMAIL_ADDRESSES" sort="natural">
         <key  column="person_id"/>
   
         <one-to-many class="cs683.EmailAddress" />   
      </set>

etc.

CS 683 Fall 04 Doc 32, Mapping Collections Slide # 15
Options for Sort

<set name="addresses" inverse="false" cascade="all" 
      table="EMAIL_ADDRESSES" sort="natural">

Sort can be any of

unsorted
natural
Name of a classes implementing java.util.Comparator

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 16

People

package cs683;
   
import java.util.TreeSet;
   
public class Person {
   String firstName;
   String lastName;
   SortedSet addresses =  new TreeSet();
   long id;
   
   public Person () { super(); }
   
   public Person(String first, String last) {
      firstName = first;
      lastName = last;
   }
   
   public SortedSet getAddresses() {
      return addresses;
   }
   public void setAddresses(SortedSet addresses) {
      this.addresses = addresses;
   }
   public void addAddress(EmailAddress newAddress) {
      addresses.add( newAddress);
      newAddress.setOwner(this);
   }

etc

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 17

EmailAddress

public class EmailAddress implements Comparable
   {
   String userName;
   String host;
   long id;
   Person owner;
   
   public Person getOwner()
      {
      return owner;
      }
   
   public int compareTo(Object anEmailAddress)
      {
      EmailAddress address = (EmailAddress)anEmailAddress;
      return (userName + host).compareTo(address.getUserName() + 
            address.getHost());
      }

Set/get methods not shown

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 18

Comparator

Permits a sorted collection to

package cs683;
   
import java.util.Comparator;
   
public class EmailComparator implements Comparator
   {
   public int compare(Object a, Object b)
      {
      EmailAddress first = (EmailAddress)a;
      EmailAddress last = (EmailAddress)b;
      return (first.host + first.userName).compareTo(last.host + 
         last.userName);
      }
   }

      <set name="addresses" inverse="false" cascade="all" 
            table="EMAIL_ADDRESSES" 
            sort="cs683.EmailComparator">
         <key  column="person_id"/>

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 19

Map

HashMap, Hashtable & TreeMap are instances of a map

Tables

People

id	first_name	last_name
1	Roger	Whitney
2	Leland	Beck
3	Carl	Eckberg

Email_Addresses

id	user_name	host	person_id	Alias
1	beck	cs.sdsu.edu	2	chair
2	whitney	cs.sdsu.edu	1	main
3	whitney	rohan.sdsu.edu	1	backup

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 20

People.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
   
<hibernate-mapping package="cs683">
   <class
      name="Person"
      table="people"
   >
      <id
         name="id"
         type="long"
         column="id"
      >
         <generator class="increment"/>
      </id>
   
      <map name="addresses" inverse="false" cascade="all" 
               table="EMAIL_ADDRESSES">
         <key  column="person_id"/>
         <index column="alias" type="string" />
         <one-to-many class="cs683.EmailAddress" />
      </map>

etc.

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 21

People

package cs683;
   
import java.util.HashMap;
   
public class Person {
   String firstName;
   String lastName;
   Map addresses =  new HashMap();
   long id;
   
   public Person () { super(); }
   
   public Person(String first, String last) {
      firstName = first;
      lastName = last;
   }
   
   public Map getAddresses() { return addresses; }
   public void setAddresses(Map addresses) {
      this.addresses = addresses;
   }
   
   public void addAddress(String index, EmailAddress newAddress) {
      addresses.put(index, newAddress);
      newAddress.setOwner(this);
   }

etc

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 22

Sample Write

static void sampleWrite() throws MappingException, HibernateException,
         Exception
      {
      Session session = getHibernateSession();
      Transaction save = null;
      try
         {
         save = session.beginTransaction();
         Person newPerson = new Person("Roger", "Whitney");
   
         EmailAddress a = new EmailAddress("whitney", "cs.sdsu.edu");
         EmailAddress b = new EmailAddress("whitney", "rohan.sdsu.edu");
         newPerson.addAddress("main", a);
         newPerson.addAddress("backup", b);
         session.save(a);
         session.save(b);
         session.save(newPerson);
         newPerson = new Person("Leland", "Beck");
         a = new EmailAddress("beck", "cs.sdsu.edu");
         newPerson.addAddress("chair", a);
         session.save(a);
         session.save(newPerson);
         newPerson = new Person("Carl", "Eckberg");
         session.save(newPerson);
         save.commit();
         }
      catch (Exception problem)

etc.

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 23

Glorp Dictionary Mapping

Example – Address Book

Address book contains dictionary of People

TablesPeople

id	first_name	last_name
1	Leland	Beck
2	Roger	Whitney

Address_Book

id	title
1	Work
2	Dance

Address_Book_Links

person_id	address_book_id	person_key
1	1	Chair
2	1	OO
1	1	Security
2	2	Email Person

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 24

Classes

AddressBook

Smalltalk defineClass: #AddressBook
   superclass: #{Core.Object}
   indexedType: #none
   private: false
   instanceVariableNames: 'id title entries '
   classInstanceVariableNames: ''
   imports: ''
   category: 'GlorpExperiments'

AddressBook class methods

title: aString
   ^super new setTitle: aString

AddressBook instance methods

at: aString
   ^entries at: aString
   
at: aString put: aPerson
   entries at: aString put: aPerson
   
title
   ^title 
   
setTitle: aString
   title := aString.
   entries := Dictionary new.

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 25

Person

Smalltalk defineClass: #Person
   superclass: #{Core.Object}
   indexedType: #none
   private: false
   instanceVariableNames: 'firstName lastName id '
   classInstanceVariableNames: ''
   imports: ''
   category: 'GlorpExperiments'

add needed accessor methods

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 26

Mapping

Smalltalk defineClass: #GlorpTutorialDescriptor
   superclass: #{Glorp.DescriptorSystem}
   indexedType: #none
   private: false
   instanceVariableNames: ''
   classInstanceVariableNames: ''
   imports: 'Glorp.*'
   category: 'GlorpExperiments'
   
allTableNames
   ^#( 'PEOPLE'  'ADDRESS_BOOK' 'ADDRESS_BOOK_LINKS' )
   
constructAllClasses
   ^(super constructAllClasses)
      add: Person;
      add: AddressBook;
      yourself
   
classModelForAddressBook: aClassModel
   aClassModel newAttributeNamed: #id.
   aClassModel newAttributeNamed: #title.
   aClassModel newAttributeNamed: #entries collection: Dictionary of: Person.
   
classModelForPerson: aClassModel
   aClassModel newAttributeNamed: #lastName.
   aClassModel newAttributeNamed: #firstName.
   aClassModel newAttributeNamed: #id.

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 27

descriptorForAddressBook: aDescriptor 
   | table linkTable |
   table := self tableNamed: 'ADDRESS_BOOK'.
   linkTable := self tableNamed: 'ADDRESS_BOOK_LINKS'.
   aDescriptor table: table.
   aDescriptor addMapping: (DirectMapping from: #id to: (table fieldNamed: 'id')).
   aDescriptor addMapping: 
      (DirectMapping from: #title to: (table fieldNamed: 'title')).
   aDescriptor addMapping: ((BasicDictionaryMapping new)
            attributeName: #entries;
            referenceClass: Person;
            keyField: (linkTable fieldNamed: 'person_key');
            relevantLinkTableFields: 
               (Array with: (linkTable fieldNamed: 'person_id')))
   
descriptorForPerson: aDescriptor 
   | personTable |
   personTable := self tableNamed: 'PEOPLE'.
   aDescriptor table: personTable.
   (aDescriptor newMapping: DirectMapping)  
      from: #id to: (personTable fieldNamed: 'id').
   (aDescriptor newMapping: DirectMapping)  
      from: #firstName to: (personTable fieldNamed: 'first_name').
   (aDescriptor newMapping: DirectMapping)  
      from: #lastName to: (personTable fieldNamed: 'last_name').

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 28


tableForADDRESS_BOOK: aTable 
   (aTable createFieldNamed: 'title' type: (platform varChar: 50)).
   (aTable createFieldNamed: 'id' type: (platform sequence)) bePrimaryKey.
   
tableForADDRESS_BOOK_LINKS: aTable 
   | personId bookId |
   personId := aTable createFieldNamed: 'person_id' type: platform int4.
   aTable 
      addForeignKeyFrom: personId 
      to: ((self tableNamed: 'PEOPLE') fieldNamed: 'id').
   bookId := aTable createFieldNamed: 'address_book_id' type: (platform varChar: 50).
   aTable 
      addForeignKeyFrom: bookId 
      to: ((self tableNamed: 'ADDRESS_BOOK') fieldNamed: 'id').
   aTable createFieldNamed: 'person_key' type: (platform varChar: 30).
   
tableForPEOPLE: aTable 
   (aTable createFieldNamed: 'first_name' type: (platform varChar: 50)).
   (aTable createFieldNamed: 'last_name' type: (platform varChar: 50)).
   (aTable createFieldNamed: 'id' type: (platform sequence)) bePrimaryKey.

CS 683 Fall 04

Doc 32, Mapping Collections Slide # 29

Adding an AddressBook to the database.

session inUnitOfWorkDo:
   [addresses := AddressBook title: 'work'.
   addresses 
      at: 'musicMan' put: (Person first: 'Sam' last: 'Hinton');
      at: 'author' put: (Person first: 'Martin' last: 'Fowler');
      at: 'self' put: (Person first: 'Roger' last: 'Whitney').
   session register: addresses].

2004 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA.

OpenContent license defines the copyright on this document.

Previous visitors since 02-Dec-04 Next

Contents

References

Mapping Collections

Bag

Tables

People

Email_Addresses

People.hbm.xml

People Class

List

Tables

People

Email_Addresses

People.hbm.xml

Person

Arrays

Tables

People

Email_Addresses

People.hbm.xml

Person

Sorted Collection

Tables

People

Email_Addresses

People.hbm.xml

CS 683 Fall 04Doc 32, Mapping Collections Slide # 15Options for Sort

People

EmailAddress

Comparator

Map

Tables

People

Email_Addresses

People.hbm.xml

People

Sample Write

Glorp Dictionary Mapping

Example – Address Book

TablesPeople

Address_Book

Address_Book_Links

Classes

AddressBook

AddressBook class methods

AddressBook instance methods

Person

Mapping

Adding an AddressBook to the database.

CS 683 Fall 04 Doc 32, Mapping Collections Slide # 15
Options for Sort