org.mmbase.module.core
Class MMTable

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

Direct Known Subclasses:

MMObjectBuilder

public abstract class MMTable
extends FunctionProvider

MMTable is the base abstraction of a cloud of objects stored in one database table, essentially a cloud of objects of the same type. It provides a starting point for MMObjectBuilder by defining a scope - the database table - and basic functionality to create the table and query properties such as its size. This class does not contain actual management of nodes (this is left to MMOBjectBuilder).

Version:

$Id: MMTable.java 43919 2010-12-14 11:57:11Z michiel $

Author:

Daniel Ockeloen, Pierre van Rooden (javadoc)

Field Summary

protected int	maxNodesFromQuery Maximum number of nodes to return on a query (-1 means no limit, and is also the default)
protected MMBase	mmb The MMBase module that this table belongs to
protected StorageConnector	storageConnector
protected String	tableName The table name

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

functions, getFunctions

Constructor Summary

MMTable()
Empty constructor.

Method Summary

int	count(NodeSearchQuery query) Counts number of nodes matching a specified constraint.
int	count(String where) Deprecated. Use count(NodeSearchQuery) instead.
boolean	created() Check whether the table is accessible.
String	getFullTableName() Retrieve the full table name (including the clouds' base name)
MMBase	getMMBase() Return the MMBase object
MMObjectNode	getNode(int number, boolean useCache) Retrieves a node based on it's number (a unique key).
List<MMObjectNode>	getNodes() Returns all the nodes from the builder.
protected List<MMObjectNode>	getNodes(Collection<MMObjectNode> virtuals) Convert virtual nodes to real nodes based on their otype Normally a multirelations-search will return virtual nodes.
List<MMObjectNode>	getNodes(NodeSearchQuery query) Returns nodes matching a specified constraint.
int	getNodeType(int number) Retrieves an object's type.
StorageConnector	getStorageConnector()
String	getTableName() Retrieve the table name (without the clouds' base name)
Enumeration<MMObjectNode>	search(String where) Deprecated. Use getNodes(NodeSearchQuery to perform a node search.
Vector<MMObjectNode>	searchVector(String where) Deprecated. Use getNodes(NodeSearchQuery to perform a node search.
void	setMMBase(MMBase m) Set the MMBase object, and retrieve the storage layer.
void	setTableName(String tableName) Set tablename of the builder.
int	size() Determine the number of objects in this table.

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

addFunction, createParameters, getFunction, getFunctions, getFunctionValue, newFunctionInstance

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

mmb

protected MMBase mmb

The MMBase module that this table belongs to

tableName

protected String tableName

The table name

maxNodesFromQuery

protected int maxNodesFromQuery

Maximum number of nodes to return on a query (-1 means no limit, and is also the default)

storageConnector

protected StorageConnector storageConnector

Constructor Detail

MMTable

public MMTable()

Empty constructor.

Method Detail

setMMBase

public void setMMBase(MMBase m)

Set the MMBase object, and retrieve the storage layer.

Parameters:

m - the MMBase object to set as owner of this builder

getMMBase

public MMBase getMMBase()

Return the MMBase object

Since:

1.7

setTableName

public void setTableName(String tableName)

Set tablename of the builder. Should be used to initialize a MMTable object before calling init().

Parameters:

tableName - the name of the table

getTableName

public String getTableName()

Retrieve the table name (without the clouds' base name)

Returns:

a String containing the table name

Since:

MMBase-1.7

getFullTableName

public String getFullTableName()

Retrieve the full table name (including the clouds' base name)

Returns:

a String containing the full table name

Since:

MMBase-1.7

size

public int size()

Determine the number of objects in this table.

Returns:

The number of entries in the table.

created

public boolean created()

Check whether the table is accessible. In general, this means the table does not exist. Please note that this routine may also return false if the table is inaccessible due to insufficient rights.

Returns:

true if the table is accessible, false otherwise.

getStorageConnector

public StorageConnector getStorageConnector()

getNode

public MMObjectNode getNode(int number,
                            boolean useCache)

Retrieves a node based on it's number (a unique key).

Parameters:

number - The number of the node to search for

useCache - If true, the node is retrieved from the node cache if possible.

Returns:

null if the node does not exist, the key is invalid,or a MMObjectNode containing the contents of the requested node.

To Do:

when something goes wrong, the method currently catches the exception and returns null. It should actually throw a NotFoundException instead.

getNodeType

public int getNodeType(int number)

Retrieves an object's type. If necessary, the type is added to the cache.

Parameters:

number - The number of the node to search for

Returns:

an int value which is the object type (otype) of the node.

To Do:

when something goes wrong, the method currently catches the exception and returns -1. It should actually throw a NotFoundException instead.

getNodes

protected List<MMObjectNode> getNodes(Collection<MMObjectNode> virtuals)

Convert virtual nodes to real nodes based on their otype Normally a multirelations-search will return virtual nodes. These nodes will only contain values which where specified in the field-vector. This method will make real nodes of those virtual nodes.

Parameters:

virtuals - containing virtual nodes

Returns:

List containing real nodes, directly from this Builders

Since:

MMBase-1.6.2

count

public int count(String where)

Deprecated. Use count(NodeSearchQuery) instead.

Counts number of nodes matching a specified constraint.

Parameters:

where - The constraint, can be a SQL where-clause, a MMNODE expression or an altavista-formatted expression.

Returns:

The number of nodes, or -1 when failing to retrieve the data.

count

public int count(NodeSearchQuery query)
          throws SearchQueryException

Counts number of nodes matching a specified constraint. The constraint is specified by a query that selects nodes of a specified type, which must be the nodetype corresponding to this builder.

Parameters:

query - The query.

Returns:

The number of nodes.

Throws:

IllegalArgumentException - when an invalid argument is supplied.

SearchQueryException - when failing to retrieve the data.

Since:

MMBase-1.7

getNodes

public List<MMObjectNode> getNodes(NodeSearchQuery query)
                            throws SearchQueryException

Returns nodes matching a specified constraint. The constraint is specified by a query that selects nodes of a specified type, which must be the nodetype corresponding to this builder.

Parameters:

query - The query.

Returns:

The nodes.

Throws:

IllegalArgumentException - When the nodetype specified by the query is not the nodetype corresponding to this builder.

SearchQueryException

Since:

MMBase-1.7

search

public Enumeration<MMObjectNode> search(String where)

Deprecated. Use getNodes(NodeSearchQuery to perform a node search.

Enumerate all the objects that match the searchkeys

Parameters:

where - scan expression that the objects need to fulfill

Returns:

an Enumeration containing all the objects that apply.

searchVector

public Vector<MMObjectNode> searchVector(String where)

Deprecated. Use getNodes(NodeSearchQuery to perform a node search.

Returns a vector containing all the objects that match the searchkeys

Parameters:

where - scan expression that the objects need to fulfill

Returns:

a vector containing all the objects that apply.

getNodes

public List<MMObjectNode> getNodes()

Returns all the nodes from the builder.

Returns:

The nodes.