cc.redberry.core.tensor.iterator

Class TreeTraverseIterator<T extends Payload<T>>

java.lang.Object

cc.redberry.core.tensor.iterator.TreeTraverseIterator<T>

public final class TreeTraverseIterator<T extends Payload<T>>
extends java.lang.Object

An iterator for tensors that allows the programmer to traverse the tensor tree structure, modify the tensor during iteration, and obtain information about iterator current position in the tensor. A TensorTreeIterator has current element, so all methods are defined in terms of the cursor position. *

Example:

      Tensor tensor = Tensors.parse("Cos[a+b+Sin[x]]");
      TensorIterator iterator = new TreeTraverseIterator(tensor);
      TraverseState state;
      while ((state = iterator.next()) != null)
           System.out.println(state + " " + iterator.depth() + " " + iterator.current());
 

This code will print:

    Entering   Cos[a+b+Sin[y*c+x]]
    Entering   a+b+Sin[y*c+x]
    Entering   a
    Leaving   a
    Entering   b
    Leaving   b
    Entering   Sin[y*c+x]
    Entering   y*c+x
    Entering   y*c
    Entering   y
    Leaving   y
    Entering   c
    Leaving   c
    Leaving   y*c
    Entering   x
    Leaving   x
    Leaving   y*c+x
    Leaving   Sin[y*c+x]
    Leaving   a+b+Sin[y*c+x]
    Leaving   Cos[a+b+Sin[y*c+x]]
 

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
TreeTraverseIterator(Tensor tensor)
TreeTraverseIterator(Tensor tensor, PayloadFactory<T> payloadFactory)
TreeTraverseIterator(Tensor tensor, TraverseGuide guide)
TreeTraverseIterator(Tensor tensor, TraverseGuide guide, PayloadFactory<T> payloadFactory)

Method Summary

Modifier and Type	Method and Description
boolean	checkLevel(Indicator<Tensor> indicator, int level) Checks specified condition at position specified by relative level to current cursor.
Tensor	current() Returns current cursor.
StackPosition<T>	currentStackPosition() Current StackPosition
int	depth() Returns depth in the tree, relatively to the current cursor position.
boolean	isUnder(Indicator<Tensor> indicator, int searchDepth)
TraverseState	next() Moves iterator to the next state.
Tensor	result() Return the resulting tensor.
void	set(Tensor tensor) Replaces the current cursor with the specified element.

Methods inherited from class java.lang.Object

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

Constructor Detail

TreeTraverseIterator

public TreeTraverseIterator(Tensor tensor,
                            TraverseGuide guide,
                            PayloadFactory<T> payloadFactory)

TreeTraverseIterator

public TreeTraverseIterator(Tensor tensor,
                            TraverseGuide guide)

TreeTraverseIterator

public TreeTraverseIterator(Tensor tensor)

TreeTraverseIterator

public TreeTraverseIterator(Tensor tensor,
                            PayloadFactory<T> payloadFactory)

Method Detail

next

public TraverseState next()

Moves iterator to the next state.

Returns:

next traverse state or null if there is no next element

set

public void set(Tensor tensor)

Replaces the current cursor with the specified element.

Parameters:

tensor - the element with which to replace the current cursor

depth

public int depth()

Returns depth in the tree, relatively to the current cursor position. Note that depth is counted from zero (e.g. zero will be returned after first next()). If next() never called or last next() was null , this method returns -1.

Returns:

depth in the tree relatively to the current cursor position

isUnder

public boolean isUnder(Indicator<Tensor> indicator,
                       int searchDepth)

checkLevel

public boolean checkLevel(Indicator<Tensor> indicator,
                          int level)

Checks specified condition at position specified by relative level to current cursor.

Parameters:

indicator - level relative position of element to be tested

Returns:

true if condition satisfies at specified level

current

public Tensor current()

Returns current cursor.

Returns:

current cursor.

result

public Tensor result()

Return the resulting tensor.

Returns:

the resulting tensor

currentStackPosition

public StackPosition<T> currentStackPosition()

Current StackPosition

Returns:

current StackPosition