org.openanzo.glitter.syntax.abstrakt
Class TreeNode

java.lang.Object
  org.openanzo.glitter.syntax.abstrakt.TreeNode

Direct Known Subclasses:

GraphPattern

public abstract class TreeNode
extends java.lang.Object

A TreeNode is the (abstract) base class for all nodes in the abstract syntax of a SPARQL query. TreeNodes also maintain a cache of properties calculated recursively over a node and its descendants.

Author:

Lee Feigenbaum

Constructor Summary

TreeNode()

Method Summary

abstract void	addChild(TreeNode child) Adds the given child at the end of this node's children.
boolean	containsVariable(Variable v)
java.util.Map<Variable,java.lang.Integer>	getBindableVariableCount()
java.util.Set<Variable>	getBindableVariableSet()
abstract java.util.Iterator<? extends TreeNode>	getChildren()
java.util.Set<Expression>	getFilters() Default implementation of getFilters().
java.util.Set<Expression>	getInScopeFilterSet()
TreeNode	getParent()
TreeNode	getRoot()
java.util.Map<Variable,java.lang.Integer>	getVariableCount()
java.util.Set<Variable>	getVariableSet()
void	invalidateCache() Invalidate the entire cache.
void	invalidateCache(java.lang.String key) Clear the cache corresponding to the given key
boolean	mightBindVariable(Variable v)
void	prettyPrint(java.lang.StringBuffer output) Pretty prints this tree node to the given StringBuffer.
void	prettyPrint(java.lang.StringBuffer output, boolean deep) Pretty prints this tree node to the given StringBuffer.
abstract boolean	removeChild(TreeNode child) Removes the given child from the collection of children
abstract boolean	replaceChild(TreeNode oldChild, TreeNode newChild) Changes the tree below this node by replacing oldChild with newChild

Methods inherited from class java.lang.Object

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

Constructor Detail

TreeNode

public TreeNode()

Method Detail

invalidateCache

public void invalidateCache(java.lang.String key)

Clear the cache corresponding to the given key

Parameters:

key -

invalidateCache

public void invalidateCache()

Invalidate the entire cache.

getParent

public TreeNode getParent()

Returns:

The parent of this TreeNode. If this is the root of a query, returns null.

getChildren

public abstract java.util.Iterator<? extends TreeNode> getChildren()

Returns:

An Iterator over the children of this node.

replaceChild

public abstract boolean replaceChild(TreeNode oldChild,
                                     TreeNode newChild)

Changes the tree below this node by replacing oldChild with newChild

Parameters:

oldChild -

newChild -

Returns:

true if the oldChild was found and replaced; false otherwise.

removeChild

public abstract boolean removeChild(TreeNode child)

Removes the given child from the collection of children

Parameters:

child -

Returns:

true if the child was found and removed; false otherwise.

addChild

public abstract void addChild(TreeNode child)

Adds the given child at the end of this node's children.

Parameters:

child -

containsVariable

public final boolean containsVariable(Variable v)

Parameters:

v -

Returns:

whether or not this node and its subtree contains Variable v.

mightBindVariable

public final boolean mightBindVariable(Variable v)

Parameters:

v -

Returns:

whether or not this node and its subtree contains Variable v in a position that it could receive bindings (e.g., a variable in a FILTER cannot receive bindings, but a variable in the GRAPH clause can.

getVariableCount

public final java.util.Map<Variable,java.lang.Integer> getVariableCount()

Returns:

A map from variables to counts for all variables that appear in this node and its descendants.

getBindableVariableCount

public final java.util.Map<Variable,java.lang.Integer> getBindableVariableCount()

Returns:

A map from variables to counts for all variables that appear in this node and its descendants. This only counts instances of Variables that can receive bindings. (As in mightBindVariable(Variable).

getVariableSet

public final java.util.Set<Variable> getVariableSet()

Returns:

A set of all variables that occur in this node and its descendants.

getBindableVariableSet

public final java.util.Set<Variable> getBindableVariableSet()

Returns:

A set of all variables that occur in this node and its descendants that may receive bindings.

getRoot

public final TreeNode getRoot()

Returns:

The root of the tree that contains this TreeNode.

getInScopeFilterSet

public final java.util.Set<Expression> getInScopeFilterSet()

Returns:

A set of all filters Expressions that are in scope (act on the bindings) for this tree node.

getFilters

public java.util.Set<Expression> getFilters()

Default implementation of getFilters(). Most tree nodes cannot contain filters.

Returns:

Default implementation of getFilters().

prettyPrint

public void prettyPrint(java.lang.StringBuffer output)

Pretty prints this tree node to the given StringBuffer.

Parameters:

output -

prettyPrint

public void prettyPrint(java.lang.StringBuffer output,
                        boolean deep)

Pretty prints this tree node to the given StringBuffer.

Parameters:

output -

deep - If true, recurse into descendants. Otherwise, includes an elipsis ("...") for any children.