EvalContext (Apache Commons JXPath 1.4-SNAPSHOT API)

java.lang.Object
- org.apache.commons.jxpath.ri.EvalContext

All Implemented Interfaces:

Iterator, ExpressionContext

Direct Known Subclasses:

AncestorContext, AttributeContext, ChildContext, DescendantContext, InitialContext, NamespaceContext, NodeSetContext, ParentContext, PrecedingOrFollowingContext, PredicateContext, RootContext, SelfContext
```
public abstract class EvalContext
extends Object
implements ExpressionContext, Iterator
```
An XPath evaluation context. When evaluating a path, a chain of EvalContexts is created, each context in the chain representing a step of the path. Subclasses of EvalContext implement behavior of various XPath axes: "child::", "parent::" etc.

Version:

$Revision: 1234255 $ $Date: 2012-01-21 04:11:46 +0100 (Sa, 21 Jan 2012) $

Author:

Dmitri Plotnikov

Field Summary

Fields
Modifier and Type Field and Description

protected EvalContext parentContext
parent context

protected int position
position

protected RootContext rootContext
root context

Fields
Modifier and Type	Field and Description
`protected EvalContext`	`parentContext` parent context
`protected int`	`position` position
`protected RootContext`	`rootContext` root context

Constructor Summary

Constructors
Constructor and Description

EvalContext(EvalContext parentContext)
Create a new EvalContext.

Constructors
Constructor and Description
`EvalContext(EvalContext parentContext)` Create a new EvalContext.

Method Summary

Methods
Modifier and Type	Method and Description
`List`	`getContextNodeList()` Returns the list of all Pointers in this context for the current position of the parent context.
`Pointer`	`getContextNodePointer()` Get the current context node.
`abstract NodePointer`	`getCurrentNodePointer()` Returns the current context node.
`int`	`getCurrentPosition()` Get the current position.
`int`	`getDocumentOrder()` Determines the document order for this context.
`JXPathContext`	`getJXPathContext()` Get the JXPathContext in which this function is being evaluated.
`NodeSet`	`getNodeSet()` Returns the list of all Pointers in this context for all positions of the parent contexts.
`int`	`getPosition()` Returns the current context position.
`RootContext`	`getRootContext()` Returns the root context of the path, which provides easy access to variables and functions.
`Pointer`	`getSingleNodePointer()` Returns the first encountered Pointer that matches the current context's criteria.
`Object`	`getValue()` Typically returns the NodeSet by calling getNodeSet(), but will be overridden for contexts that more naturally produce individual values, e.g.
`boolean`	`hasNext()` Returns true if there are mode nodes matching the context's constraints.
`boolean`	`isChildOrderingRequired()` Even if this context has the natural ordering and therefore does not require collecting and sorting all nodes prior to returning them, such operation may be required for any child context.
`Object`	`next()` Returns the next node pointer in the context
`abstract boolean`	`nextNode()` Returns true if there is another object in the current set.
`boolean`	`nextSet()` Returns true if there is another sets of objects to interate over.
`void`	`remove()` Operation is not supported
`void`	`reset()` Sets current position = 0, which is the pre-iteration state.
`boolean`	`setPosition(int position)` Moves the current position to the specified index.
`protected void`	`sortPointers(List l)` Sort a list of pointers based on document order.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - parentContext
```
protected EvalContext parentContext
```
    parent context
  - rootContext
```
protected RootContext rootContext
```
    root context
  - position
```
protected int position
```
    position
- Constructor Detail
  - EvalContext
```
public EvalContext(EvalContext parentContext)
```
    Create a new EvalContext.
    
    Parameters:
    parentContext - parent context
- Method Detail
  - getContextNodePointer
```
public Pointer getContextNodePointer()
```
    Description copied from interface: ExpressionContext
    
    Get the current context node.
    
    Specified by:
    
    getContextNodePointer in interface ExpressionContext
    
    Returns:
    The current context node pointer.
  - getJXPathContext
```
public JXPathContext getJXPathContext()
```
    Description copied from interface: ExpressionContext
    
    Get the JXPathContext in which this function is being evaluated.
    
    Specified by:
    
    getJXPathContext in interface ExpressionContext
    
    Returns:
    A list representing the current context nodes.
  - getPosition
```
public int getPosition()
```
    Description copied from interface: ExpressionContext
    
    Returns the current context position.
    
    Specified by:
    
    getPosition in interface ExpressionContext
    
    Returns:
    int
  - getDocumentOrder
```
public int getDocumentOrder()
```
    Determines the document order for this context.
    
    Returns:
    1 ascending order, -1 descending order, 0 - does not require ordering
  - isChildOrderingRequired
```
public boolean isChildOrderingRequired()
```
    Even if this context has the natural ordering and therefore does not require collecting and sorting all nodes prior to returning them, such operation may be required for any child context.
    
    Returns:
    boolean
  - hasNext
```
public boolean hasNext()
```
    Returns true if there are mode nodes matching the context's constraints.
    
    Specified by:
    
    hasNext in interface Iterator
    
    Returns:
    boolean
  - next
```
public Object next()
```
    Returns the next node pointer in the context
    
    Specified by:
    
    next in interface Iterator
    
    Returns:
    Object
  - remove
```
public void remove()
```
    Operation is not supported
    
    Specified by:
    
    remove in interface Iterator
    
    Throws:
    
    UnsupportedOperationException
  - sortPointers
```
protected void sortPointers(List l)
```
    Sort a list of pointers based on document order.
    
    Parameters:
    l - the list to sort.
  - getContextNodeList
```
public List getContextNodeList()
```
    Returns the list of all Pointers in this context for the current position of the parent context.
    
    Specified by:
    
    getContextNodeList in interface ExpressionContext
    
    Returns:
    List
  - getNodeSet
```
public NodeSet getNodeSet()
```
    Returns the list of all Pointers in this context for all positions of the parent contexts. If there was an ongoing iteration over this context, the method should not be called.
    
    Returns:
    NodeSet
  - getValue
```
public Object getValue()
```
    Typically returns the NodeSet by calling getNodeSet(), but will be overridden for contexts that more naturally produce individual values, e.g. VariableContext
    
    Returns:
    Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getRootContext
```
public RootContext getRootContext()
```
    Returns the root context of the path, which provides easy access to variables and functions.
    
    Returns:
    RootContext
  - reset
```
public void reset()
```
    Sets current position = 0, which is the pre-iteration state.
  - getCurrentPosition
```
public int getCurrentPosition()
```
    Get the current position.
    
    Returns:
    int position.
  - getSingleNodePointer
```
public Pointer getSingleNodePointer()
```
    Returns the first encountered Pointer that matches the current context's criteria.
    
    Returns:
    Pointer
  - getCurrentNodePointer
```
public abstract NodePointer getCurrentNodePointer()
```
    Returns the current context node. Undefined before the beginning of the iteration.
    
    Returns:
    NodePoiner
  - nextSet
```
public boolean nextSet()
```
    Returns true if there is another sets of objects to interate over. Resets the current position and node.
    
    Returns:
    boolean
  - nextNode
```
public abstract boolean nextNode()
```
    Returns true if there is another object in the current set. Switches the current position and node to the next object.
    
    Returns:
    boolean
  - setPosition
```
public boolean setPosition(int position)
```
    Moves the current position to the specified index. Used with integer predicates to quickly get to the n'th element of the node set. Returns false if the position is out of the node set range. You can call it with 0 as the position argument to restart the iteration.
    
    Parameters:
    position - to set
    
    Returns:
    boolean

Class EvalContext

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

parentContext

rootContext

position

Constructor Detail

EvalContext

Method Detail

getContextNodePointer

getJXPathContext

getPosition

getDocumentOrder

isChildOrderingRequired

hasNext

next

remove

sortPointers

getContextNodeList

getNodeSet

getValue

toString

getRootContext

reset

getCurrentPosition

getSingleNodePointer

getCurrentNodePointer

nextSet

nextNode

setPosition