org.mmbase.module.core
Class VirtualNode

java.lang.Object
  |
  +--org.mmbase.module.core.MMObjectNode
        |
        +--org.mmbase.module.core.VirtualNode

All Implemented Interfaces:

SizeMeasurable

Direct Known Subclasses:

ClusterNode, TypeRel.VirtualTypeRelNode

public class VirtualNode

extends MMObjectNode

VirtualNode is a representation of a virtual objectnode. Virtual Object nodes are nodes that are not stored in a databasetable. Note that a temporary node is not virtual. This class captures a number of methods that would normally require datbase access, such as obtaining relations or determining age of a node.

Version:

26 Apr 2001

Author:

Pierre van Rooden

Fields inherited from class org.mmbase.module.core.MMObjectNode

alias, changed, parent, prefix, properties, values, virtual

Constructor Summary

VirtualNode(MMObjectBuilder parent)
Main contructor.

Method Summary

boolean	commit() commit : commits the node to the database or other storage system.
int	getAge() Returns the node's age A virtual node is always new (0)
int	getRelationCount() Returns the number of relations of this node.
int	getRelationCount(java.lang.String wantedtype) Return the number of relations of this node, filtered on a specified type.
java.util.Enumeration	getRelations() Return the relations of this node.
boolean	hasRelations() Returns whether this node has relations.
int	insert(java.lang.String userName) Insert is not implemented on a virtual node.

Methods inherited from class org.mmbase.module.core.MMObjectNode

clearChanged, defaultEquals, delPropertiesCache, delRelationsCache, equals, getAlias, getAllRelations, getBooleanValue, getBuilder, getByteSize, getByteSize, getByteValue, getChanged, getDBState, getDBType, getDoubleValue, getFloatValue, getFunctionValue, getGUIIndicator, getIntegerValue, getIntValue, getLongValue, getName, getNodeValue, getNumber, getOType, getProperties, getProperty, getRelatedNodes, getRelatedNodes, getRelatedNodes, getRelatedNodes, getRelationCacheHits, getRelationCacheMiss, getRelations, getRelations, getStringValue, getTableName, getValue, getValues, getXMLValue, hashCode, insertDone, isChanged, isVirtual, preEdit, putProperty, removeRelations, retrieveValue, sendFieldChangeSignal, setAlias, setValue, setValue, setValue, setValue, setValue, setValue, storeValue, testValidData, toString, toXML, toXML

Methods inherited from class java.lang.Object

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

Constructor Detail

VirtualNode

public VirtualNode(MMObjectBuilder parent)

Main contructor.

Parameters:

parent - the node's parent, generally (but not necessarily) an instance of a virtual builder.

Method Detail

commit

public boolean commit()

commit : commits the node to the database or other storage system. Generally, commiting a virtual node has no effect, so the basic implementation returns false.

Overrides:

commit in class MMObjectNode

Returns:

false

insert

public int insert(java.lang.String userName)

Insert is not implemented on a virtual node.

Overrides:

insert in class MMObjectNode

Returns:

nothing, throws an exception

hasRelations

public boolean hasRelations()

Returns whether this node has relations. A virtual node never has relations.

Overrides:

hasRelations in class MMObjectNode

Returns:

false

getRelations

public java.util.Enumeration getRelations()

Return the relations of this node. A virtual node never has relations.

Overrides:

getRelations in class MMObjectNode

Returns:

empty Enumeration

getRelationCount

public int getRelationCount()

Returns the number of relations of this node. A virtual node never has relations.

Overrides:

getRelationCount in class MMObjectNode

Returns:

0

getRelationCount

public int getRelationCount(java.lang.String wantedtype)

Return the number of relations of this node, filtered on a specified type. A virtual node never has relations.

Overrides:

getRelationCount in class MMObjectNode

Parameters:

wantedtype - the 'type' of related nodes (NOT the relations!).

Returns:

An int indicating the number of nodes found

getAge

public int getAge()

Returns the node's age A virtual node is always new (0)

Overrides:

getAge in class MMObjectNode

Returns:

the age in days (0)