org.mmbase.storage.search

Interface RelationStep

All Superinterfaces:

Step

All Known Implementing Classes:

BasicRelationStep, RemoteRelationStep_Proxy

public interface RelationStep
extends Step

A relationstep refers to a table of relations between the previous and next step. Relationstep are used to create a path of related objects.

This corresponds to a constraint joining the three tables in SQL SELECT-syntax.

Note that tables can also be joined using FieldCompareConstraints.

Since:

MMBase-1.7

Version:

$Id$

Author:

Rob van Maris

Field Summary

Fields

Modifier and Type	Field and Description
static String[]	DIRECTIONALITY_DESCRIPTIONS Directionality names corresponding to the direction values.
static int	DIRECTIONS_ALL Directionality following relations both ways, including unidirectional relations.
static int	DIRECTIONS_BOTH Directionality following relations both ways (source to destination AND destination to source).
static int	DIRECTIONS_DESTINATION Directionality following relations from source to destination.
static int	DIRECTIONS_EITHER Directionality following relations from destination to source.
static int	DIRECTIONS_SOURCE Directionality following relations from destination to source.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) Compares this relationstep to the specified object.
boolean	getCheckedDirectionality() Gets the value of the checkedDirectionality property.
int	getDirectionality() Gets the directionality mode used with this relation.
Step	getNext() Gets the next step.
Step	getPrevious() Gets the previous step.
Integer	getRole() Gets the role for this relation, if specified.
int	hashCode()
String	toString() Returns a string representation of this RelationStep.

Methods inherited from interface org.mmbase.storage.search.Step

addNode, getAlias, getNodes, getTableName, setUnmodifiable

Field Detail

DIRECTIONS_BOTH

static final int DIRECTIONS_BOTH

Directionality following relations both ways (source to destination AND destination to source). Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.

See Also:

Constant Field Values

DIRECTIONS_DESTINATION

static final int DIRECTIONS_DESTINATION

Directionality following relations from source to destination. E.g. where the previous step is source and the next step is destination. Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.

See Also:

Constant Field Values

DIRECTIONS_SOURCE

static final int DIRECTIONS_SOURCE

Directionality following relations from destination to source. E.g. where the previous step is destination and the next step is source. This value ignores the value of the checkedDirectionality property.

See Also:

Constant Field Values

DIRECTIONS_ALL

static final int DIRECTIONS_ALL

Directionality following relations both ways, including unidirectional relations. This value ignores the value of the checkedDirectionality property.

See Also:

Constant Field Values

DIRECTIONS_EITHER

static final int DIRECTIONS_EITHER

Directionality following relations from destination to source. E.g. where the previous step is destination and the next step is source. Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.

See Also:

Constant Field Values

DIRECTIONALITY_DESCRIPTIONS

static final String[] DIRECTIONALITY_DESCRIPTIONS

Directionality names corresponding to the direction values. As a result DIRECTIONALITY_DESCRIPTIONS[directionality] is the directionality name: "both", "destination", "source", "all" or "either".

Method Detail

getCheckedDirectionality

boolean getCheckedDirectionality()

Gets the value of the checkedDirectionality property. This property determines how uni/bi-directionality affects which relations are followed from destination to source, when the directionality property is set to DIRECTIONS_SOURCE or DIRECTIONS_BOTH.

When this value is true, only bi-directional relations are followed from destination to source. Otherwise unidirectional relations are followed from destination to source as well.

getDirectionality

int getDirectionality()

Gets the directionality mode used with this relation. This is one of values defined in this class.

getRole

Integer getRole()

Gets the role for this relation, if specified. I.e. the nodenumber of the corresponding RelDef node, or null.

getPrevious

Step getPrevious()

Gets the previous step.

getNext

Step getNext()

Gets the next step.

equals

boolean equals(Object obj)

Compares this relationstep to the specified object. The result is true if and only if the argument is a non-null RelationStep object with the same directionality and role, associated with the same tablename, using the same alias and including the same nodes.

Specified by:

equals in interface Step

Overrides:

equals in class Object

Parameters:

obj - The object to compare with.

Returns:

true if the objects are equal, false otherwise.

See Also:

Step.equals(java.lang.Object)

hashCode

int hashCode()

Specified by:

hashCode in interface Step

Overrides:

hashCode in class Object

toString

String toString()

Returns a string representation of this RelationStep. The string representation has the form "RelationStep(tablename:<tablename>, alias:<alias>, nodes:<nodes>, dir:<dir>, role:<role>)" where

• <tablename> is the tablename returnedby getTableName()
• <alias> is the alias returned by getAlias()
• <nodes> is the string representation of the ordered list of nodenumbers returned by getNodes()
• <dir> is the name of the directionality returned by getDirectionality()
• <role> is the role returned by getRole()

Specified by:

toString in interface Step

Overrides:

toString in class Object

Returns:

A string representation of this RelationStep.