com.xmlmind.xml.xpath

Class OutermostExprContext

java.lang.Object

com.xmlmind.xml.xpath.OutermostExprContext

All Implemented Interfaces:

ExprContext

Direct Known Subclasses:

ExprContextImpl

public class OutermostExprContext
extends Object
implements ExprContext

An implementation of ExprContext which can be used to evaluate outermost expressions (i.e. an expression that is not part of another expression).

Though non-abstract for unit testing reasons, this basic implementation is intended to be subclassed.

Constructor Summary

Constructors

Constructor and Description
OutermostExprContext()

Method Summary

Modifier and Type	Method and Description
XNode	findElementWithId(XNode node, String id) Returns null because this basic implementation is not schema-aware.
XNode	getCurrent(XNode contextNode) Returns its context node argument because "current()".eval(node) should return node.
NodeIterator	getDocument(String uriRef, URL baseURL) Returns NullNodeIterator.INSTANCE because this basic implementation does not know how to load documents.
NodeIterator	getKeyedNodes(Name keyName, String keyValue, XNode node) Returns NullNodeIterator.INSTANCE because this basic implementation does not support key().
int	getLastPosition() Returns 1 because in outermost_expression.eval(node) the current node list just contains node.
int	getPosition() Returns 1 because in outermost_expression.eval(node) the current node list just contains node.
Variant	getVariableValue(Name name, XNode node) Returns null because this basic implementation does not handle variable references.
boolean	isElementWithId(XNode node, String id) Returns false because this basic implementation is not schema aware.

Methods inherited from class java.lang.Object

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

Constructor Detail

OutermostExprContext

public OutermostExprContext()

Method Detail

getPosition

public int getPosition()
                throws EvalException

Returns 1 because in outermost_expression.eval(node) the current node list just contains node.

Specified by:

getPosition in interface ExprContext

Throws:

EvalException

getLastPosition

public int getLastPosition()
                    throws EvalException

Returns 1 because in outermost_expression.eval(node) the current node list just contains node.

Specified by:

getLastPosition in interface ExprContext

Throws:

EvalException

getVariableValue

public Variant getVariableValue(Name name,
                                XNode node)
                         throws EvalException

Returns null because this basic implementation does not handle variable references.

Specified by:

getVariableValue in interface ExprContext

node - the context node. Generally not useful.

Throws:

EvalException

getCurrent

public XNode getCurrent(XNode contextNode)

Returns its context node argument because "current()".eval(node) should return node.

In practice, this method is never invoked because the single only useful implementation of this method is in private class WithCurrentExpr.

Specified by:

getCurrent in interface ExprContext

Parameters:

contextNode - the context node. For an outermost expression (an expression not occurring within another expression), the current node is always the same as the context node.

Returns:

the current node

findElementWithId

public XNode findElementWithId(XNode node,
                               String id)
                        throws EvalException

Returns null because this basic implementation is not schema-aware.

Specified by:

findElementWithId in interface ExprContext

Parameters:

node - used to specify the document

id - searched ID value

Returns:

element in document specified by node having specified ID if any; null otherwise

Throws:

EvalException - if a problem occurs during the search

isElementWithId

public boolean isElementWithId(XNode node,
                               String id)
                        throws EvalException

Returns false because this basic implementation is not schema aware.

Specified by:

isElementWithId in interface ExprContext

Parameters:

node - node possibly having an ID attribute

id - ID value to be matched against the possible ID attribute of node

Returns:

true if specified node has an ID attribute having specified value; false otherwise

Throws:

EvalException - if a problem occurs during the match

getDocument

public NodeIterator getDocument(String uriRef,
                                URL baseURL)
                         throws EvalException

Returns NullNodeIterator.INSTANCE because this basic implementation does not know how to load documents.

Specified by:

getDocument in interface ExprContext

Parameters:

uriRef - specifies nodes (using a fragment) in a document

baseURL - URL possibly used to resolve relative URL in uriRef; may be null

Returns:

nodes specified by uriRef

Throws:

EvalException - if a problem occurs during the operation

See Also:

NullNodeIterator

getKeyedNodes

public NodeIterator getKeyedNodes(Name keyName,
                                  String keyValue,
                                  XNode node)
                           throws EvalException

Returns NullNodeIterator.INSTANCE because this basic implementation does not support key().

Specified by:

getKeyedNodes in interface ExprContext

Parameters:

keyName - name of the key

keyValue - searched value

node - the context node.

Returns:

nodes belonging to the same document as node having specified key with specified value.

The returned nodes don't need to be sorted by document order.

Throws:

EvalException - if a problem occurs during the operation