Hibernate ORM - hibernate-core 5.6.15.Final · org.hibernate.persister.walking.spi.AssociationKey

public Class AssociationKey

extends Object

Class Inheritance

java.lang.Object
org.hibernate.persister.walking.spi.AssociationKey

Imports

java.util.Arrays

Used to uniquely identify a foreign key, so that we don't join it more than once creating circularities. Note that the table+columns refers to the association owner. These are used to help detect bi-directional associations since the Hibernate runtime metamodel (persisters) do not inherently know this information. For example, consider the Order -> Customer and Customer -> Order(s) bi-directional association; both would be mapped to the ORDER_TABLE.CUST_ID column. That is the purpose of this struct.

Bit of a misnomer to call this an association attribute. But this follows the legacy use of AssociationKey from old JoinWalkers to denote circular join detection

Authors

Steve Ebersole, Gail Badner, Gavin King

Field Summary

Modifier and Type	Field and Description
private final String[]	columns
private String	str
private final String	table

Constructor Summary

Access	Constructor and Description
public	AssociationKey(String The table part of the association key table, String[] The columns that define the association key columns) Create the AssociationKey.

Method Summary

Modifier and Type	Method and Description
public boolean	equals(Object the reference object with which to compare. o) Overrides java.lang.Object.equals. Indicates whether some other object is "equal to" this one.
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for the object.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll wait wait wait

Field Detail

columns	back to summary
private final String[] columns

str	back to summary
private String str

table	back to summary
private final String table

Constructor Detail

AssociationKey	back to summary
public AssociationKey(String table, String[] columns) Create the AssociationKey. Parameters table:String The table part of the association key columns:String[] The columns that define the association key

AssociationKey

back to summary

public AssociationKey(String table, String[] columns)

Create the AssociationKey.

Parameters

table:String: The table part of the association key
columns:String[]: The columns that define the association key

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object o) Overrides java.lang.Object.equals. Doc from java.lang.Object.equals. Indicates whether some other object is "equal to" this one. The `equals` method implements an equivalence relation on non-null object references: It is reflexive: for any non-null reference value `x`, `x.equals(x)` should return `true`. It is symmetric: for any non-null reference values `x` and `y`, `x.equals(y)` should return `true` if and only if `y.equals(x)` returns `true`. It is transitive: for any non-null reference values `x`, `y`, and `z`, if `x.equals(y)` returns `true` and `y.equals(z)` returns `true`, then `x.equals(z)` should return `true`. It is consistent: for any non-null reference values `x` and `y`, multiple invocations of `x.equals(y)` consistently return `true` or consistently return `false`, provided no information used in `equals` comparisons on the objects is modified. For any non-null reference value `x`, `x.equals(null)` should return `false`. An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes. Parameters o:Object the reference object with which to compare. Returns:boolean `true` if this object is the same as the obj argument; `false` otherwise. Annotations @Override

public boolean equals(Object o)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

It is reflexive: for any non-null reference value x, x.equals(x) should return true.
It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters

o:Object: the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Doc from java.lang.Object.hashCode. Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by `java.util.HashMap`. The general contract of `hashCode` is: Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. Returns:int a hash code value for this object. Annotations @Override

public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Returns:int

a hash code value for this object.

Annotations

@Override

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations

@Override