org.apache.cayenne.query
Class PrefetchTreeNode

java.lang.Object
  org.apache.cayenne.query.PrefetchTreeNode

All Implemented Interfaces:

java.io.Serializable, XMLSerializable

public class PrefetchTreeNode
extends java.lang.Object
implements java.io.Serializable, XMLSerializable

Defines a node in a prefetch tree.

Since:

1.2

Author:

Andrus Adamchik

See Also:

Serialized Form

Field Summary

protected java.util.Collection	children
static int	DISJOINT_PREFETCH_SEMANTICS
static int	JOINT_PREFETCH_SEMANTICS
protected java.lang.String	name
protected PrefetchTreeNode	parent
protected boolean	phantom
protected int	semantics
static int	UNDEFINED_SEMANTICS

Constructor Summary

	PrefetchTreeNode() Creates a root node of the prefetch tree.
protected	PrefetchTreeNode(PrefetchTreeNode parent, java.lang.String segmentPath) Creates a phantom PrefetchTreeNode, initializing it with parent node and a name of a relationship segment connecting this node with the parent.

Method Summary

void	addChild(PrefetchTreeNode child)
PrefetchTreeNode	addPath(java.lang.String path) Adds a "path" with specified semantics to this prefetch node.
java.util.Collection	adjacentJointNodes() Returns a subset of nodes with "joint" semantics that are to be prefetched in the same query as the current node.
java.util.Collection	disjointNodes() Returns a collection of PrefetchTreeNodes with disjoint semantics.
void	encodeAsXML(XMLEncoder encoder) Prints itself as XML to the provided XMLEncoder.
protected PrefetchTreeNode	getChild(java.lang.String segment)
java.util.Collection	getChildren() Returns an unmodifiable collection of children.
java.lang.String	getName()
PrefetchTreeNode	getNode(java.lang.String path) Looks up an existing node in the tree desribed by the dot-separated path.
PrefetchTreeNode	getParent()
java.lang.String	getPath() Returns full prefetch path, that is a dot separated String of node names starting from root and up to and including this node.
java.lang.String	getPath(PrefetchTreeNode upTillParent)
PrefetchTreeNode	getRoot() Returns the root of the node tree.
int	getSemantics()
boolean	hasChildren()
boolean	isDisjointPrefetch()
boolean	isJointPrefetch()
boolean	isPhantom()
java.util.Collection	jointNodes() Returns a collection of PrefetchTreeNodes in this tree with joint semantics.
java.util.Collection	nonPhantomNodes() Returns a collection of PrefetchTreeNodes that are not phantoms.
void	removeChild(PrefetchTreeNode child)
protected void	removeChild(java.lang.String segment)
void	removePath(java.lang.String path) Removes or makes phantom a node defined by this path.
void	setPhantom(boolean phantom)
void	setSemantics(int semantics)
void	traverse(PrefetchProcessor processor) Traverses the tree depth-first, invoking callback methods of the processor when passing through the nodes.

Methods inherited from class java.lang.Object

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

Field Detail

UNDEFINED_SEMANTICS

public static final int UNDEFINED_SEMANTICS

See Also:

Constant Field Values

JOINT_PREFETCH_SEMANTICS

public static final int JOINT_PREFETCH_SEMANTICS

See Also:

Constant Field Values

DISJOINT_PREFETCH_SEMANTICS

public static final int DISJOINT_PREFETCH_SEMANTICS

See Also:

Constant Field Values

name

protected java.lang.String name

phantom

protected boolean phantom

semantics

protected int semantics

parent

protected transient PrefetchTreeNode parent

children

protected java.util.Collection children

Constructor Detail

PrefetchTreeNode

public PrefetchTreeNode()

Creates a root node of the prefetch tree. Children can be added to the parent by calling "addPath".

PrefetchTreeNode

protected PrefetchTreeNode(PrefetchTreeNode parent,
                           java.lang.String segmentPath)

Creates a phantom PrefetchTreeNode, initializing it with parent node and a name of a relationship segment connecting this node with the parent.

Method Detail

encodeAsXML

public void encodeAsXML(XMLEncoder encoder)

Description copied from interface: XMLSerializable

Prints itself as XML to the provided XMLEncoder.

Specified by:

encodeAsXML in interface XMLSerializable

getRoot

public PrefetchTreeNode getRoot()

Returns the root of the node tree. Root is the topmost parent node that itself has no parent set.

getPath

public java.lang.String getPath()

Returns full prefetch path, that is a dot separated String of node names starting from root and up to and including this node. Note that root "name" is considered to be an empty string.

getPath

public java.lang.String getPath(PrefetchTreeNode upTillParent)

adjacentJointNodes

public java.util.Collection adjacentJointNodes()

Returns a subset of nodes with "joint" semantics that are to be prefetched in the same query as the current node. Result excludes this node, regardless of its semantics.

jointNodes

public java.util.Collection jointNodes()

Returns a collection of PrefetchTreeNodes in this tree with joint semantics.

disjointNodes

public java.util.Collection disjointNodes()

Returns a collection of PrefetchTreeNodes with disjoint semantics.

nonPhantomNodes

public java.util.Collection nonPhantomNodes()

Returns a collection of PrefetchTreeNodes that are not phantoms.

traverse

public void traverse(PrefetchProcessor processor)

Traverses the tree depth-first, invoking callback methods of the processor when passing through the nodes.

getNode

public PrefetchTreeNode getNode(java.lang.String path)

Looks up an existing node in the tree desribed by the dot-separated path. Will return null if no matching child exists.

addPath

public PrefetchTreeNode addPath(java.lang.String path)

Adds a "path" with specified semantics to this prefetch node. All yet non-existent nodes in the created path will be marked as phantom.

Returns:

the last segment in the created path.

removePath

public void removePath(java.lang.String path)

Removes or makes phantom a node defined by this path. If the node for this path doesn't have any children, it is removed, otherwise it is made phantom.

addChild

public void addChild(PrefetchTreeNode child)

removeChild

public void removeChild(PrefetchTreeNode child)

removeChild

protected void removeChild(java.lang.String segment)

getChild

protected PrefetchTreeNode getChild(java.lang.String segment)

getParent

public PrefetchTreeNode getParent()

getChildren

public java.util.Collection getChildren()

Returns an unmodifiable collection of children.

hasChildren

public boolean hasChildren()

getName

public java.lang.String getName()

isPhantom

public boolean isPhantom()

setPhantom

public void setPhantom(boolean phantom)

getSemantics

public int getSemantics()

setSemantics

public void setSemantics(int semantics)

isJointPrefetch

public boolean isJointPrefetch()

isDisjointPrefetch

public boolean isDisjointPrefetch()