org.javarosa.xpath

Class XPathNodeset

java.lang.Object

org.javarosa.xpath.XPathNodeset

Direct Known Subclasses:

XPathLazyNodeset

public class XPathNodeset
extends Object

Represents a set of XPath nodes returned from a path or other operation which acts on multiple paths. Current encompasses two states. 1) A nodeset which references between 0 and N nodes which are known about (but, for instance, don't match any predicates or are irrelevant). Some operations cannot be evaluated in this state directly. If more than one node is referenced, it is impossible to return a normal evaluation, for instance. 2) A nodeset which wasn't able to reference into any known model (generally a reference which is written in error). In this state, the size of the nodeset can be evaluated, but the actual reference cannot be returned, since it doesn't have any semantic value. (2) may be a deviation from normal XPath. This should be evaluated in the future.

Author:

ctsims

Field Summary

Fields

Modifier and Type	Field and Description
protected EvaluationContext	ec
protected DataInstance	instance

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	XPathNodeset(DataInstance instance, EvaluationContext ec) for lazy evaluation
	XPathNodeset(List<TreeReference> nodes, DataInstance instance, EvaluationContext ec) Construct an XPath nodeset.

Method Summary

Modifier and Type	Method and Description
static XPathNodeset	ConstructInvalidPathNodeset(String pathEvaluated, String originalPath)
protected XPathTypeMismatchException	getInvalidNodesetException()
int	getNonEmptySize()
TreeReference	getRefAt(int i)
List<TreeReference>	getReferences()
Object	getValAt(int i)
protected String	nodeContents()
protected void	setReferences(List<TreeReference> nodes)
static XPathNodeset	shuffle(XPathNodeset input) Builds and returns a copy of a XPathNodeset with nodes in a randomized order.
static XPathNodeset	shuffle(XPathNodeset input, long seed) Builds and returns a copy of a XPathNodeset with nodes in a randomized order.
int	size()
Object[]	toArgList()
Object	unpack()

Methods inherited from class java.lang.Object

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

Field Detail

instance

protected DataInstance instance

ec

protected EvaluationContext ec

Constructor Detail

XPathNodeset

protected XPathNodeset(DataInstance instance,
                       EvaluationContext ec)

for lazy evaluation

Parameters:

instance -

ec -

XPathNodeset

public XPathNodeset(List<TreeReference> nodes,
                    DataInstance instance,
                    EvaluationContext ec)

Construct an XPath nodeset.

Parameters:

nodes -

instance -

ec -

Method Detail

ConstructInvalidPathNodeset

public static XPathNodeset ConstructInvalidPathNodeset(String pathEvaluated,
                                                       String originalPath)

shuffle

public static XPathNodeset shuffle(XPathNodeset input)

Builds and returns a copy of a XPathNodeset with nodes in a randomized order.

Returns:

a copy of this nodeset with nodes in a randomized order

shuffle

public static XPathNodeset shuffle(XPathNodeset input,
                                   long seed)

Builds and returns a copy of a XPathNodeset with nodes in a randomized order.

Parameters:

seed - the seed used when building a Random object to get reproducible results. If null, no seed is used

Returns:

a copy of this nodeset with nodes in a randomized order

setReferences

protected void setReferences(List<TreeReference> nodes)

getReferences

public List<TreeReference> getReferences()

unpack

public Object unpack()

Returns:

The value represented by this xpath. Can only be evaluated when this xpath represents exactly one reference, or when it represents 0 references after a filtering operation (a reference which _could_ have existed, but didn't, rather than a reference which could not represent a real node).

toArgList

public Object[] toArgList()

size

public int size()

getNonEmptySize

public int getNonEmptySize()

Returns:

The number of nodes that are not empty

getRefAt

public TreeReference getRefAt(int i)

getValAt

public Object getValAt(int i)

getInvalidNodesetException

protected XPathTypeMismatchException getInvalidNodesetException()

nodeContents

protected String nodeContents()