de.grogra.imp3d
Class Visitor3D

java.lang.Object
  de.grogra.imp3d.Visitor3D

All Implemented Interfaces:

Visitor

Direct Known Subclasses:

DisplayVisitor, PickRayVisitor

public abstract class Visitor3D
extends java.lang.Object
implements Visitor

This base implementation of the Visitor interface tracks information about the current coordinate transformation and layer of objects. Invocations of visit methods are forwarded to the abstract methods visitEnterImpl(Object, boolean, Path) and visitLeaveImpl(Object, boolean, Path).

Author:

Ole Kniemeyer

Field Summary

protected int	layer The current layer.
protected GraphState	state The graph state in which this visitor runs.
protected Matrix4d	transformation The current transformation from local coordinates to global coordinates.

Fields inherited from interface de.grogra.graph.Visitor

STOP

Constructor Summary

Visitor3D()

Method Summary

Matrix4d	getCurrentTransformation() Returns the current affine transformation from local coordinates to global coordinates.
GraphState	getGraphState() Returns the graph state within which the visitor is operating.
protected void	init(GraphState gs, EdgePattern pattern, Matrix4d t) Initializes this visitor.
protected java.lang.Object	visitEnter(java.lang.Object object, boolean asNode, Path path)
java.lang.Object	visitEnter(Path path, boolean node) Informs this visitor about a node or edge in the graph.
protected abstract void	visitEnterImpl(java.lang.Object object, boolean asNode, Path path) This method has to be implemented by subclasses.
java.lang.Object	visitInstanceEnter() Informs this visitor about the beginning of an instantiation.
boolean	visitInstanceLeave(java.lang.Object o) Informs this visitor that an instantiation has been processed completely.
boolean	visitLeave(java.lang.Object o, Path path, boolean node) Informs this visitor that a node or an edge has been processed completely.
protected abstract void	visitLeaveImpl(java.lang.Object object, boolean asNode, Path path) This method has to be implemented by subclasses.

Methods inherited from class java.lang.Object

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

Field Detail

layer

protected int layer

The current layer.

state

protected GraphState state

The graph state in which this visitor runs.

transformation

protected Matrix4d transformation

The current transformation from local coordinates to global coordinates.

Constructor Detail

Visitor3D

public Visitor3D()

Method Detail

getCurrentTransformation

public Matrix4d getCurrentTransformation()

Returns the current affine transformation from local coordinates to global coordinates.

Returns:

current coordinate transformation

getGraphState

public GraphState getGraphState()

Description copied from interface: Visitor

Returns the graph state within which the visitor is operating.

Specified by:

getGraphState in interface Visitor

Returns:

graph state of visitor

init

protected void init(GraphState gs,
                    EdgePattern pattern,
                    Matrix4d t)

Initializes this visitor.

Parameters:

gs - the graph state in which the visitor runs

pattern - the pattern which is used to extract the scene tree to visit from the complete graph

t - the initial transformation from local to global coordinates

visitEnter

protected java.lang.Object visitEnter(java.lang.Object object,
                                      boolean asNode,
                                      Path path)

visitEnter

public java.lang.Object visitEnter(Path path,
                                   boolean node)

Description copied from interface: Visitor

Informs this visitor about a node or edge in the graph. path contains the path from the root up to and including the node or, in case an edge is visited, the edge and its terminal node. Later on, Visitor.visitLeave(java.lang.Object, de.grogra.graph.Path, boolean) will be invoked with the returned value of this invocation, path and node as arguments. If this method returns Visitor.STOP, the corresponding visitLeave-method will be invoked immediately after this method, i.e., the visitor does not dive more deeply in the hierarchy. Otherwise, if a node is visited and there are instantiations associated with or edges connected with it (regardless of their direction), their corresponding visitor methods will be invoked inbetween. Likewise, if an edge is visited, its indicent terminal node will be visited next.

Specified by:

visitEnter in interface Visitor

Parameters:

path - current path

node - do we enter a node or an edge?

Returns:

value to pass to visitLeave, may be Visitor.STOP

visitEnterImpl

protected abstract void visitEnterImpl(java.lang.Object object,
                                       boolean asNode,
                                       Path path)

This method has to be implemented by subclasses. It is invoked when object is entered.

Parameters:

object - the object being entered

asNode - is object a node or an edge?

path - the path to object if object is a node, the path to the node where object points to if object is an edge

visitInstanceEnter

public java.lang.Object visitInstanceEnter()

Description copied from interface: Visitor

Informs this visitor about the beginning of an instantiation. This method invokation is nested immediately within visitEnter/visitLeave of a node. Later on, Visitor.visitInstanceLeave(Object) will be invoked with the returned value of this invocation as argument. If this method returns Visitor.STOP, the visitInstanceLeave-method will be invoked immediately after this method, i.e., the visitor does not dive into the instantiation. Otherwise, the instantiation is performed, starting with an edge.

Specified by:

visitInstanceEnter in interface Visitor

Returns:

value to pass to visitInstanceLeave, may be Visitor.STOP

visitInstanceLeave

public boolean visitInstanceLeave(java.lang.Object o)

Description copied from interface: Visitor

Informs this visitor that an instantiation has been processed completely. The value o is the return value of the corresponding invocation of Visitor.visitInstanceEnter(). If this invocation returns false, no further instantiations or edges of the current level of hierarchy will be passed to this visitor, i.e., the visitLeave method for the enclosing node will be invoked immediately.

Specified by:

visitInstanceLeave in interface Visitor

Parameters:

o - returned value of visitInstanceEnter

Returns:

true iff processing of current level shall be continued

visitLeave

public boolean visitLeave(java.lang.Object o,
                          Path path,
                          boolean node)

Description copied from interface: Visitor

Informs this visitor that a node or an edge has been processed completely. The value o is the return value of the corresponding invocation of Visitor.visitEnter(de.grogra.graph.Path, boolean). In case of a node and if this invocation returns false, no further edges of the current level of hierarchy will be passed to this visitor, i.e., the visitLeave methods for the enclosing edge and node will be invoked immediately. Likewise, in case of an edge and a return value false, no further instantiations or edges of the current level of hierarchy will be passed to this visitor, i.e., the visitLeave method for the enclosing node will be invoked immediately.

Specified by:

visitLeave in interface Visitor

Parameters:

o - returned value of visitEnter

path - current path to node

node - do we leave a node or an edge?

Returns:

true iff processing of current level shall be continued

visitLeaveImpl

protected abstract void visitLeaveImpl(java.lang.Object object,
                                       boolean asNode,
                                       Path path)

This method has to be implemented by subclasses. It is invoked when object is left.

Parameters:

object - the object being left

asNode - is object a node or an edge?

path - the path to object if object is a node, the path to the node where object points to if object is an edge