/*
* Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution. The Eclipse Public License is available
* at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
* is available at http://www.eclipse.org/org/documents/edl-v10.php.
*/
package javax.persistence;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static javax.persistence.FetchType.LAZY;
Defines a many-valued association with many-to-many multiplicity.
Every many-to-many association has two sides, the owning side and the non-owning, or inverse, side. The
join table is specified on the owning side. If the association is bidirectional, either side may be
designated as the owning side. If the relationship is bidirectional, the non-owning side must use the
mappedBy element of the ManyToMany annotation to specify the relationship field
or property of the owning side.
The join table for the relationship, if not defaulted, is specified on the owning side.
The ManyToMany annotation may be used within an embeddable class contained within an entity
class to specify a relationship to a collection of entities. If the relationship is bidirectional and the
entity containing the embeddable class is the owner of the relationship, the non-owning side must use the
mappedBy element of the ManyToMany annotation to specify the relationship field
or property of the embeddable class. The dot (".") notation syntax must be used in the
mappedBy element to indicate the relationship attribute within the embedded attribute. The
value of each identifier used with the dot notation is the name of the respective embedded field or
property.
Example 1:
// In Customer class:
@ManyToMany
@JoinTable(name="CUST_PHONES")
public Set<PhoneNumber> getPhones() { return phones; }
// In PhoneNumber class:
@ManyToMany(mappedBy="phones")
public Set<Customer> getCustomers() { return customers; }
Example 2:
// In Customer class:
@ManyToMany(targetEntity=com.acme.PhoneNumber.class)
public Set getPhones() { return phones; }
// In PhoneNumber class:
@ManyToMany(targetEntity=com.acme.Customer.class, mappedBy="phones")
public Set getCustomers() { return customers; }
Example 3:
// In Customer class:
@ManyToMany
@JoinTable(name="CUST_PHONE",
joinColumns=
@JoinColumn(name="CUST_ID", referencedColumnName="ID"),
inverseJoinColumns=
@JoinColumn(name="PHONE_ID", referencedColumnName="ID")
)
public Set<PhoneNumber> getPhones() { return phones; }
// In PhoneNumberClass:
@ManyToMany(mappedBy="phones")
public Set<Customer> getCustomers() { return customers; }
See Also: - JoinTable
Since: Java Persistence 1.0
/**
* Defines a many-valued association with many-to-many multiplicity.
* <p>
* Every many-to-many association has two sides, the owning side and the non-owning, or inverse, side. The
* join table is specified on the owning side. If the association is bidirectional, either side may be
* designated as the owning side. If the relationship is bidirectional, the non-owning side must use the
* <code>mappedBy</code> element of the <code>ManyToMany</code> annotation to specify the relationship field
* or property of the owning side.
* <p>
* The join table for the relationship, if not defaulted, is specified on the owning side.
* <p>
* The <code>ManyToMany</code> annotation may be used within an embeddable class contained within an entity
* class to specify a relationship to a collection of entities. If the relationship is bidirectional and the
* entity containing the embeddable class is the owner of the relationship, the non-owning side must use the
* <code>mappedBy</code> element of the <code>ManyToMany</code> annotation to specify the relationship field
* or property of the embeddable class. The dot (".") notation syntax must be used in the
* <code>mappedBy</code> element to indicate the relationship attribute within the embedded attribute. The
* value of each identifier used with the dot notation is the name of the respective embedded field or
* property.
* <p>
* <pre>
*
* Example 1:
*
* // In Customer class:
*
* @ManyToMany
* @JoinTable(name="CUST_PHONES")
* public Set<PhoneNumber> getPhones() { return phones; }
*
* // In PhoneNumber class:
*
* @ManyToMany(mappedBy="phones")
* public Set<Customer> getCustomers() { return customers; }
*
* Example 2:
*
* // In Customer class:
*
* @ManyToMany(targetEntity=com.acme.PhoneNumber.class)
* public Set getPhones() { return phones; }
*
* // In PhoneNumber class:
*
* @ManyToMany(targetEntity=com.acme.Customer.class, mappedBy="phones")
* public Set getCustomers() { return customers; }
*
* Example 3:
*
* // In Customer class:
*
* @ManyToMany
* @JoinTable(name="CUST_PHONE",
* joinColumns=
* @JoinColumn(name="CUST_ID", referencedColumnName="ID"),
* inverseJoinColumns=
* @JoinColumn(name="PHONE_ID", referencedColumnName="ID")
* )
* public Set<PhoneNumber> getPhones() { return phones; }
*
* // In PhoneNumberClass:
*
* @ManyToMany(mappedBy="phones")
* public Set<Customer> getCustomers() { return customers; }
* </pre>
*
* @see JoinTable
* @since Java Persistence 1.0
*/
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface ManyToMany {
(Optional) The entity class that is the target of the association. Optional only if the
collection-valued relationship property is defined using Java generics. Must be specified otherwise.
Defaults to the parameterized type of the collection when defined using generics.
Returns: The target entity
/**
* (Optional) The entity class that is the target of the association. Optional only if the
* collection-valued relationship property is defined using Java generics. Must be specified otherwise.
* <p>
* Defaults to the parameterized type of the collection when defined using generics.
*
* @return The target entity
*/
Class targetEntity() default void.class;
(Optional) The operations that must be cascaded to the target of the association.
When the target collection is a java.util.Map, the cascade element
applies to the map value.
Defaults to no operations being cascaded.
Returns: The cascade type
/**
* (Optional) The operations that must be cascaded to the target of the association.
* <p>
* When the target collection is a {@link java.util.Map java.util.Map}, the <code>cascade</code> element
* applies to the map value.
* <p>
* Defaults to no operations being cascaded.
*
* @return The cascade type
*/
CascadeType[] cascade() default {};
(Optional) Whether the association should be lazily loaded or must be eagerly fetched. The EAGER
strategy is a requirement on the persistence provider runtime that the associated entities must be
eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime.
Returns: The fetch type
/**
* (Optional) Whether the association should be lazily loaded or must be eagerly fetched. The EAGER
* strategy is a requirement on the persistence provider runtime that the associated entities must be
* eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime.
*
* @return The fetch type
*/
FetchType fetch() default LAZY;
The field that owns the relationship. Required unless the relationship is unidirectional.
Returns: The mappedby
/**
* The field that owns the relationship. Required unless the relationship is unidirectional.
*
* @return The mappedby
*/
String mappedBy() default "";
}