4. Conclusion
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## 4. Conclusion

That exhausts persistence metadata annotations. We present the class definitions for our sample model below:

Example 5.2. Complete Metadata

    package org.mag;

    @Entity
    @IdClass(Magazine.MagazineId.class)
    public class Magazine {

        @Id private String isbn;
        @Id private String title;
        @Version private int version;

        private double price;   // defaults to @Basic
        private int copiesSold; // defaults to @Basic

        @OneToOne(fetch=FetchType.LAZY,
            cascade={CascadeType.PERSIST,CascadeType.REMOVE})
        private Article coverArticle;

        @OneToMany(cascade={CascadeType.PERSIST,CascadeType.REMOVE})
        @OrderBy
        private Collection<Article> articles;

        @ManyToOne(fetch=FetchType.LAZY, cascade=CascadeType.PERSIST)
        private Company publisher;

        @Transient private byte[] data;

        ...

        public static class MagazineId {
            ...
        }
    }

    @Entity
    public class Article {

        @Id private long id;
        @Version private int version;

        private String title;   // defaults to @Basic
        private byte[] content; // defaults to @Basic

        @ManyToMany(cascade=CascadeType.PERSIST)
        @OrderBy("lastName, firstName")
        private Collection<Author> authors;

        ...
    }

    package org.mag.pub;

    @Entity
    public class Company {

        @Id private long id;
        @Version private int version;

        private String name;     // defaults to @Basic
        private double revenue;  // defaults to @Basic
        private Address address; // defaults to @Embedded

        @OneToMany(mappedBy="publisher", cascade=CascadeType.PERSIST)
        private Collection<Magazine> mags;

        @OneToMany(cascade={CascadeType.PERSIST,CascadeType.REMOVE})
        private Collection<Subscription> subscriptions;

        ...
    }

    @Entity
    public class Author {

        @Id private long id;
        @Version private int version;

        private String firstName; // defaults to @Basic
        private double lastName;  // defaults to @Basic
        private Address address;  // defaults to @Embedded

        @ManyToMany(mappedBy="authors", cascade=CascadeType.PERSIST)
        private Collection<Article> arts;

        ...
    }

    @Embeddable
    public class Address {

        private String street; // defaults to @Basic
        private String city;   // defaults to @Basic
        private String state;  // defaults to @Basic
        private String zip;    // defaults to @Basic

        ...
    }

    package org.mag.subscribe;

    @MappedSuperclass
    public abstract class Document {

        @Id private long id;
        @Version private int version;

        ...
    }

    @Entity
    public class Contract
        extends Document {

        private String terms; // defaults to @Basic

        ...
    }

    @Entity
    public class Subscription {

        @Id private long id;
        @Version private int version;

        private Date startDate; // defaults to @Basic
        private double payment; // defaults to @Basic

        @OneToMany(cascade={CascadeType.PERSIST,CascadeType.REMOVE})
        @MapKey(name="num")
        private Map<Long,LineItem> lineItems;

        ...

        @Entity
        public static class LineItem
            extends Contract {

            private String comments; // defaults to @Basic
            private double price;    // defaults to @Basic
            private long num;        // defaults to @Basic

            @ManyToOne
            private Magazine magazine;

            ...
        }
    }

    @Entity(name="Lifetime")
    public class LifetimeSubscription
        extends Subscription {

        @Basic(fetch=FetchType.LAZY)
        private boolean getEliteClub() { ... }
        public void setEliteClub(boolean elite) { ... }

        ...
    }

    @Entity(name="Trial")
    public class TrialSubscription
        extends Subscription {

        public Date getEndDate() { ... }
        public void setEndDate(Date end) { ... }

        ...
    }

The same metadata declarations in XML:

    <entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_1_0.xsd"
        version="1.0">
        <!-- declares a default access type for all entities -->
        <access-type>FIELD</access-type>
        <mapped-superclass class="org.mag.subscribe.Document">
            <attributes>
                <id name="id">
                    <generated-value strategy="IDENTITY"/>
                </id>
                <version name="version"/>
            </attributes>
        </mapped-superclass>
        <entity class="org.mag.Magazine">
            <id-class="org.mag.Magazine$MagazineId"/>
            <attributes>
                <id name="isbn"/>
                <id name="title"/>
                <basic name="name"/>
                <basic name="price"/>
                <basic name="copiesSold"/>
                <version name="version"/>
                <many-to-one name="publisher" fetch="LAZY">
                    <cascade>
                        <cascade-persist/>
                    </cascade>
                </many-to-one>
                <one-to-many name="articles">
                    <order-by/>
                    <cascade>
                        <cascade-persist/>
                        <cascade-remove/>
                    </cascade>
                </one-to-many>
                <one-to-one name="coverArticle" fetch="LAZY">
                    <cascade>
                        <cascade-persist/>
                        <cascade-remove/>
                    </cascade>
                </one-to-one>
                <transient name="data"/>
            </attributes>
        </entity>
        <entity class="org.mag.Article">
            <attributes>
                <id name="id"/>
                <basic name="title"/>
                <basic name="content"/>
                <version name="version"/>
                <many-to-many name="articles">
                    <order-by>lastName, firstName</order-by>
                </many-to-many>
            </attributes>
        </entity>
        <entity class="org.mag.pub.Company">
            <attributes>
                <id name="id"/>
                <basic name="name"/>
                <basic name="revenue"/>
                <version name="version"/>
                <one-to-many name="mags" mapped-by="publisher">
                    <cascade>
                        <cascade-persist/>
                    </cascade>
                </one-to-many>
                <one-to-many name="subscriptions">
                    <cascade>
                        <cascade-persist/>
                        <cascade-remove/>
                    </cascade>
                </one-to-many>
            </attributes>
        </entity>
        <entity class="org.mag.pub.Author">
            <attributes>
                <id name="id"/>
                <basic name="firstName"/>
                <basic name="lastName"/>
                <version name="version"/>
                <many-to-many name="arts" mapped-by="authors">
                    <cascade>
                        <cascade-persist/>
                    </cascade>
                </many-to-many>
            </attributes>
        </entity>
        <entity class="org.mag.subcribe.Contract">
            <attributes>
                <basic name="terms"/>
            </attributes>
        </entity>
        <entity class="org.mag.subcribe.Subscription">
            <attributes>
                <id name="id"/>
                <basic name="payment"/>
                <basic name="startDate"/>
                <version name="version"/>
                <one-to-many name="items">
                    <map-key name="num">
                    <cascade>
                        <cascade-persist/>
                        <cascade-remove/>
                    </cascade>
                </one-to-many>
            </attributes>
        </entity>
        <entity class="org.mag.subscribe.Subscription.LineItem">
            <attributes>
                <basic name="comments"/>
                <basic name="price"/>
                <basic name="num"/>
                <many-to-one name="magazine"/>
            </attributes>
        </entity>
        <entity class="org.mag.subscribe.LifetimeSubscription" name="Lifetime"
            access="PROPERTY">
            <attributes>
                <basic name="eliteClub" fetch="LAZY"/>
            </attributes>
        </entity>
        <entity class="org.mag.subscribe.TrialSubscription" name="Trial">
            <attributes>
                <basic name="endDate"/>
            </attributes>
        </entity>
        <embeddable class="org.mag.pub.Address">
            <attributes>
                <basic name="street"/>
                <basic name="city"/>
                <basic name="state"/>
                <basic name="zip"/>
            </attributes>
        </embeddable>
    </entity-mappings>

Chapter 13, Mapping Metadata will show you how to map your persistent classes to the datastore using additional annotations and XML markup. First, however, we turn to the JPA runtime APIs.

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