org.javarosa.xpath.expr

Class XPathPathExpr

java.lang.Object

org.javarosa.xpath.expr.XPathExpression

org.javarosa.xpath.expr.XPathPathExpr

All Implemented Interfaces:

Serializable, Externalizable

public class XPathPathExpr
extends XPathExpression

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
XPathFilterExpr	filtExpr
int	init_context
static int	INIT_CONTEXT_EXPR
static int	INIT_CONTEXT_RELATIVE
static int	INIT_CONTEXT_ROOT
XPathStep[]	steps

Constructor Summary

Constructors

Constructor and Description
XPathPathExpr()
XPathPathExpr(int init_context, XPathStep[] steps)
XPathPathExpr(XPathFilterExpr filtExpr, XPathStep[] steps)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
XPathNodeset	eval(DataInstance unusedDataInstance, EvaluationContext ec)
static XPathPathExpr	fromRef(TreeReference ref)
TreeReference	getReference() translate an xpath path reference into a TreeReference TreeReferences only support a subset of true xpath paths; restrictions are: simple child name tests 'child::name', '.', and '..' allowed only no predicates all '..' steps must come before anything else
static Object	getRefValue(DataInstance model, EvaluationContext ec, TreeReference ref)
boolean	matches(XPathExpression o) Warning: this method has somewhat unclear semantics.
Object	pivot(DataInstance model, EvaluationContext evalContext, List<Object> pivots, Object sentinal) Pivot this expression, returning values if appropriate, and adding any pivots to the list.
void	readExternal(DataInputStream in, PrototypeFactory pf)
String	toString()
static Object	unpackValue(IAnswerData val)
void	writeExternal(DataOutputStream out)

Methods inherited from class org.javarosa.xpath.expr.XPathExpression

eval, hashCode, pivot, print, printParseTree

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

INIT_CONTEXT_ROOT

public static final int INIT_CONTEXT_ROOT

See Also:

Constant Field Values

INIT_CONTEXT_RELATIVE

public static final int INIT_CONTEXT_RELATIVE

See Also:

Constant Field Values

INIT_CONTEXT_EXPR

public static final int INIT_CONTEXT_EXPR

See Also:

Constant Field Values

init_context

public int init_context

steps

public XPathStep[] steps

filtExpr

public XPathFilterExpr filtExpr

Constructor Detail

XPathPathExpr

public XPathPathExpr()

XPathPathExpr

public XPathPathExpr(int init_context,
                     XPathStep[] steps)

XPathPathExpr

public XPathPathExpr(XPathFilterExpr filtExpr,
                     XPathStep[] steps)

Method Detail

getReference

public TreeReference getReference()
                           throws XPathUnsupportedException

translate an xpath path reference into a TreeReference TreeReferences only support a subset of true xpath paths; restrictions are: simple child name tests 'child::name', '.', and '..' allowed only no predicates all '..' steps must come before anything else

Throws:

XPathUnsupportedException

eval

public XPathNodeset eval(DataInstance unusedDataInstance,
                         EvaluationContext ec)

Specified by:

eval in class XPathExpression

getRefValue

public static Object getRefValue(DataInstance model,
                                 EvaluationContext ec,
                                 TreeReference ref)

unpackValue

public static Object unpackValue(IAnswerData val)

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

matches

public boolean matches(XPathExpression o)

Warning: this method has somewhat unclear semantics. "matches" follows roughly the same process as equals(), in that it goes through the path step by step and compares whether each step can refer to the same node. The only difference is that match() will allow for a named step to match a step who's name is a wildcard. So \/data\/path\/to will "match" \/data\/*\/to

even though they are not equal.

Matching is reflexive, consistent, and symmetric, but _not_ transitive.

Parameters:

o -

Returns:

true if the expression is a path that matches this one

readExternal

public void readExternal(DataInputStream in,
                         PrototypeFactory pf)
                  throws IOException,
                         DeserializationException

Throws:

IOException

DeserializationException

writeExternal

public void writeExternal(DataOutputStream out)
                   throws IOException

Throws:

IOException

fromRef

public static XPathPathExpr fromRef(TreeReference ref)

pivot

public Object pivot(DataInstance model,
                    EvaluationContext evalContext,
                    List<Object> pivots,
                    Object sentinal)
             throws UnpivotableExpressionException

Description copied from class: XPathExpression

Pivot this expression, returning values if appropriate, and adding any pivots to the list.

Overrides:

pivot in class XPathExpression

Parameters:

model - The model to evaluate the current expression against

evalContext - The evaluation context to evaluate against

pivots - The list of pivot points in the xpath being evaluated. Pivots should be added to this list.

sentinal - The value which is being pivoted around.

Returns:

null - If a pivot was identified in this expression sentinal - If the current expression represents the sentinal being pivoted any other value - The result of the expression if no pivots are detected

Throws:

UnpivotableExpressionException - If the expression is too complex to pivot