org.mmbase.module.core
Class VirtualBuilder

java.lang.Object
  org.mmbase.util.functions.FunctionProvider
      org.mmbase.module.core.MMTable
          org.mmbase.module.core.MMObjectBuilder
              org.mmbase.module.core.VirtualBuilder

All Implemented Interfaces:

EventListener, NodeEventListener, RelationEventListener

Direct Known Subclasses:

ClusterBuilder, ResultBuilder, VirtualReferrerBuilder

public class VirtualBuilder

extends MMObjectBuilder

VirtualBuilder is a builder which creates 'virtual' nodes. This class is intended to facilitate practical creation of virtual builders by capturing events that migth otherwise lead to unexpected or faulty behavior.

Version:

$Id: VirtualBuilder.java,v 1.22 2006/01/16 15:17:59 michiel Exp $

Author:

Pierre van Rooden

Field Summary

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

AGE_PARAMETERS, broadCastChanges, DEFAULT_ALINEA, DEFAULT_EOL, description, descriptions, EVENT_TYPE_LOCAL, EVENT_TYPE_REMOTE, FIELD_NUMBER, FIELD_OBJECT_TYPE, FIELD_OWNER, fields, genericBlobCache, getFunctions, GUI_PARAMETERS, guiFunction, infoFunction, internalVersion, nodeCache, oType, searchAge, SYSTEM_OWNER, TEMPNODE_DEFAULT_SIZE, temporaryNodes, TMP_FIELD_NUMBER, virtual, WRAP_PARAMETERS, wrapFunction

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

maxNodesFromQuery, mmb, storageConnector, tableName

Fields inherited from class org.mmbase.util.functions.FunctionProvider

functions

Constructor Summary

	VirtualBuilder(MMBase m) Creates an instance of a Virtual builder.
protected	VirtualBuilder(MMBase m, String tableName) Creates an instance of a Virtual builder and registers it in MMBase.

Method Summary

boolean	create() Creates a new builder table in the current database.
int	getDBState(String fieldName) Return a field's database state.
Map	getFields(MMObjectNode node) Get text from a blob field from a database.
String	getGUIIndicator(MMObjectNode node) What should a GUI display for this node. Default is the first non system field (first field after owner). Override this to display your own choice (see Images.java). You may want to override MMObjectBuilder.getNodeGUIIndicator(org.mmbase.module.core.MMObjectNode, org.mmbase.util.functions.Parameters) for more flexibility. The default behavior of a virtual node is to display the content of the 'name' field (if present).
MMObjectNode	getNewNode(String owner) Get a new node, using this builder as its parent.
protected byte[]	getShortedByte(String fieldName, MMObjectNode node) Get binary data of a blob field. This function is called to 'load' a field into the node, because it was not loaded together with the node, because it is supposed to be too big. Since virtual builders are generally not associated with a database, this method returns null.
protected String	getShortedText(String fieldName, MMObjectNode node) Get text from a blob field. This function is called to 'load' a field into the node, because it was not loaded together with the node, because it is supposed to be too big. Since virtual builders are generally not associated with a database, this method returns null.
boolean	init() Initializes this builder.
int	insert(String owner, MMObjectNode node) Insert a new object (content provided) in the cloud, including an entry for the object alias (if provided).

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

addEventListener, addField, addLocalObserver, addRemoteObserver, broadcastChanges, checkAddTmpField, clearBlobCache, commit, createAlias, createAlias, delete, equals, equals, executeFunction, executeFunction, fieldLocalChanged, getAncestors, getBlobCache, getClassName, getConfigFile, getConfigResource, getDataTypeCollector, getDBKey, getDBType, getDefaultTeaser, getDefaultUrl, getDescendants, getDescription, getDescription, getDescriptions, getEditFields, getEmptyNode, getField, getFieldNames, getFields, getFields, getFunction, getFunctionParameters, getFunctions, getGUIIndicator, getGUIIndicator, getHardNode, getHardNode, getHTML, getInitParameter, getInitParameters, getInternalVersion, getList, getLocaleGUIIndicator, getLocaleGUIIndicator, getMachineName, getMaintainer, getNewTmpNode, getNextField, getNextField, getNode, getNode, getNode, getNodeFromCache, getNodeGUIIndicator, getNumber, getObjectType, getObjectValue, getParentBuilder, getPluralName, getPluralName, getPluralNames, getRelations_main, getSearchAge, getShort, getSingularName, getSingularName, getSingularNames, getSmartPath, getSortedFields, getSortedListFields, getTmpNode, getURLEncode, getValue, getVersion, getWAP, getXMLPath, hasField, hashCode, hashCode, hostname_function, insert, isExtensionOf, isNodeCached, isVirtual, newFunctionInstance, nodeLocalChanged, nodeRemoteChanged, notify, notify, preCommit, process, putTmpNode, removeEventListener, removeField, removeLocalObserver, removeNode, removeRelations, removeRemoteObserver, removeSyncNodes, removeTmpNode, replace, safeCache, sendFieldChangeSignal, setDefaults, setDescription, setDescriptions, setFields, setInitParameter, setMaintainer, setParentBuilder, setPluralNames, setSearchAge, setSingularNames, setUniqueValue, setUniqueValue, setValue, setValue, setVersion, setXMLPath, testValidData, toString, toString, update, updateFields, wrap

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

count, count, created, getFullTableName, getMMBase, getNode, getNodes, getNodes, getNodes, getNodeType, getStorageConnector, getTableName, search, searchVector, setMMBase, setTableName, size

Methods inherited from class org.mmbase.util.functions.FunctionProvider

addFunction, createParameters, getFunction, getFunctions, getFunctionValue

Methods inherited from class java.lang.Object

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

Constructor Detail

VirtualBuilder

public VirtualBuilder(MMBase m)

Creates an instance of a Virtual builder. A builder instantiated with this constrcutor is not registered in MMBase and should only be used as a temporary parent for virtual nodes which do not have a long life span.

Parameters:

m - the MMbase cloud creating the node

VirtualBuilder

protected VirtualBuilder(MMBase m,
                         String tableName)

Creates an instance of a Virtual builder and registers it in MMBase.

Parameters:

m - the MMbase cloud creating the node

tableName - the name of the builder as known in the MMbase system

Method Detail

init

public boolean init()

Initializes this builder. No specifici cation is performed. This method overrides the default emthod in MMObhjectBuilder, which would otherwise attempt to access the database.

Overrides:

init in class MMObjectBuilder

Returns:

Always true.

See Also:

create()

create

public boolean create()

Creates a new builder table in the current database. This method does not perform any action in a virtual builder, as there is no actual table associated with it.

Overrides:

create in class MMObjectBuilder

insert

public int insert(String owner,
                  MMObjectNode node)

Insert a new object (content provided) in the cloud, including an entry for the object alias (if provided). This method does not perform any action in a virtual builder.

Overrides:

insert in class MMObjectBuilder

Parameters:

owner - The administrator creating the node

node - The object to insert

Returns:

-1 (the insert failed)

getNewNode

public MMObjectNode getNewNode(String owner)

Get a new node, using this builder as its parent. The new node is a virtual node.

Overrides:

getNewNode in class MMObjectBuilder

Parameters:

owner - The administrator creating the new node.

Returns:

A newly initialized VirtualNode.

getGUIIndicator

public String getGUIIndicator(MMObjectNode node)

What should a GUI display for this node. Default is the first non system field (first field after owner). Override this to display your own choice (see Images.java). You may want to override MMObjectBuilder.getNodeGUIIndicator(org.mmbase.module.core.MMObjectNode, org.mmbase.util.functions.Parameters) for more flexibility. The default behavior of a virtual node is to display the content of the 'name' field (if present). XXX: should be changed to something better

Overrides:

getGUIIndicator in class MMObjectBuilder

Parameters:

node - The node to display

Returns:

either the name field of the node or "no info"

getDBState

public int getDBState(String fieldName)

Return a field's database state. The default behavior for a virtual node is to return DBSTATE_VIRTUAL.

Overrides:

getDBState in class MMObjectBuilder

Parameters:

fieldName - the requested field's name

Returns:

DBSTATE_VIRTUAL

getShortedText

protected String getShortedText(String fieldName,
                                MMObjectNode node)

Get text from a blob field. This function is called to 'load' a field into the node, because it was not loaded together with the node, because it is supposed to be too big. Since virtual builders are generally not associated with a database, this method returns null.

Overrides:

getShortedText in class MMObjectBuilder

Parameters:

fieldName - name of the field

node -

Returns:

null

getShortedByte

protected byte[] getShortedByte(String fieldName,
                                MMObjectNode node)

Get binary data of a blob field. This function is called to 'load' a field into the node, because it was not loaded together with the node, because it is supposed to be too big. Since virtual builders are generally not associated with a database, this method returns null.

Overrides:

getShortedByte in class MMObjectBuilder

Parameters:

fieldName - name of the field

node -

Returns:

null

getFields

public Map getFields(MMObjectNode node)

Get text from a blob field from a database.

Since:

MMBase-1.8