org.datanucleus.store.rdbms.key

Class CandidateKey

java.lang.Object

org.datanucleus.store.rdbms.key.CandidateKey

Direct Known Subclasses:

PrimaryKey

public class CandidateKey
extends Object

Representation of a Candidate key. This represents a UNIQUE key on a column or columns.

Field Summary

Fields

Modifier and Type	Field and Description
protected List<Column>	columns Columns that the key relates to.
protected String	name Name of the key.
protected Table	table Table that the key applies to.

Constructor Summary

Constructors

Constructor and Description
CandidateKey(Table table) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addColumn(Column col) Class to add a column to the key
protected void	assertSameDatastoreObject(Column col) Utility to assert if the column is for a different table.
boolean	equals(Object obj) Equality operator.
String	getColumnList() Accessor for the column list
static String	getColumnList(Collection cols) Method to return the list of columns which the key applies to.
List<Column>	getColumns() Accessor for the columns that the key relates to.
String	getName() Accessor for the key name.
Table	getTable() Accessor for the table
int	hashCode() Hashcode operator.
void	setColumn(int seq, Column col) Mutator for the column spec, to add/change a column.
protected static void	setMinSize(List list, int size)
void	setName(String name) Mutator for the key name.
int	size() Accessor for the size.
boolean	startsWith(org.datanucleus.store.rdbms.key.Key key) Check if this starts with the same columns specified in key.
String	toString() Stringify method.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

name

protected String name

Name of the key.

table

protected Table table

Table that the key applies to.

columns

protected List<Column> columns

Columns that the key relates to.

Constructor Detail

CandidateKey

public CandidateKey(Table table)

Constructor.

Parameters:

table - Table to apply this key to

Method Detail

setColumn

public void setColumn(int seq,
                      Column col)

Mutator for the column spec, to add/change a column.

Parameters:

seq - Sequence number of the column

col - The column

size

public int size()

Accessor for the size.

Returns:

The size.

equals

public boolean equals(Object obj)

Equality operator.

Parameters:

obj - Object to compare against

Returns:

Whether they are equal.

hashCode

public int hashCode()

Hashcode operator.

Returns:

The hashcode

toString

public String toString()

Stringify method.

Overrides:

toString in class Object

Returns:

String version of this object.

getName

public String getName()

Accessor for the key name.

Returns:

Key name

getTable

public Table getTable()

Accessor for the table

Returns:

table

getColumns

public List<Column> getColumns()

Accessor for the columns that the key relates to.

Returns:

the List of columns.

getColumnList

public String getColumnList()

Accessor for the column list

Returns:

The column list

addColumn

public void addColumn(Column col)

Class to add a column to the key

Parameters:

col - The column to add

startsWith

public boolean startsWith(org.datanucleus.store.rdbms.key.Key key)

Check if this starts with the same columns specified in key.

Parameters:

key - the Key (may be multiple number of columns)

Returns:

true if this columns starts with columns specified in key

setName

public void setName(String name)

Mutator for the key name.

Parameters:

name - The key name

assertSameDatastoreObject

protected void assertSameDatastoreObject(Column col)

Utility to assert if the column is for a different table.

Parameters:

col - The column to compare with

setMinSize

protected static void setMinSize(List list,
                                 int size)

getColumnList

public static String getColumnList(Collection cols)

Method to return the list of columns which the key applies to.

Parameters:

cols - The columns.

Returns:

The column list.