org.apache.commons.jxpath
Interface CompiledExpression
- JXPathCompiledExpression
public interface CompiledExpression
Represents a compiled XPath. The interpretation of compiled XPaths
may be faster, because it bypasses the compilation step. The reference
implementation of JXPathContext also globally caches some of the
results of compilation, so the direct use of JXPathContext is not
always less efficient than the use of CompiledExpression.
Use CompiledExpression only when there is a need to evaluate the
same expression multiple times and the CompiledExpression can be
conveniently cached.
To acqure a CompiledExpression, call
JXPathContext.compile
$Revision: 1.6 $ $Date: 2004/02/29 14:17:42 $ Pointer | createPath(JXPathContext context) - Creates intermediate elements of
the path by invoking an AbstractFactory, which should first be
installed on the context by calling "setFactory".
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Pointer | createPathAndSetValue(JXPathContext context, Object value) - The same as setValue, except it creates intermediate elements of
the path by invoking an AbstractFactory, which should first be
installed on the context by calling "setFactory".
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Pointer | getPointer(JXPathContext context, String xpath) - Traverses the xpath and returns a Pointer.
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Object | getValue(JXPathContext context) - Evaluates the xpath and returns the resulting object.
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Object | getValue(JXPathContext context, Class requiredType) - Evaluates the xpath, converts the result to the specified class and
returns the resulting object.
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Iterator | iterate(JXPathContext context) - Traverses the xpath and returns a Iterator of all results found
for the path.
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Iterator | iteratePointers(JXPathContext context) - Traverses the xpath and returns an Iterator of Pointers.
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void | removeAll(JXPathContext context) - Remove all graph elements described by this expression
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void | removePath(JXPathContext context) - Remove the graph element described by this expression
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void | setValue(JXPathContext context, Object value) - Modifies the value of the property described by the supplied xpath.
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createPath
public Pointer createPath(JXPathContext context)
Creates intermediate elements of
the path by invoking an AbstractFactory, which should first be
installed on the context by calling "setFactory".
createPathAndSetValue
public Pointer createPathAndSetValue(JXPathContext context,
Object value)
The same as setValue, except it creates intermediate elements of
the path by invoking an AbstractFactory, which should first be
installed on the context by calling "setFactory".
Will throw an exception if one of the following conditions occurs:
- Elements of the xpath aleady exist, by the path does not in
fact describe an existing property
- The AbstractFactory fails to create an instance for an intermediate
element.
- The property is not writable (no public, non-static set method)
getPointer
public Pointer getPointer(JXPathContext context,
String xpath)
Traverses the xpath and returns a Pointer.
A Pointer provides easy access to a property.
If the xpath matches no properties
in the graph, the pointer will be null.
getValue
public Object getValue(JXPathContext context)
Evaluates the xpath and returns the resulting object. Primitive
types are wrapped into objects.
getValue
public Object getValue(JXPathContext context,
Class requiredType)
Evaluates the xpath, converts the result to the specified class and
returns the resulting object.
iterate
public Iterator iterate(JXPathContext context)
Traverses the xpath and returns a Iterator of all results found
for the path. If the xpath matches no properties
in the graph, the Iterator will not be null.
iteratePointers
public Iterator iteratePointers(JXPathContext context)
Traverses the xpath and returns an Iterator of Pointers.
A Pointer provides easy access to a property.
If the xpath matches no properties
in the graph, the Iterator be empty, but not null.
removeAll
public void removeAll(JXPathContext context)
Remove all graph elements described by this expression
removePath
public void removePath(JXPathContext context)
Remove the graph element described by this expression
setValue
public void setValue(JXPathContext context,
Object value)
Modifies the value of the property described by the supplied xpath.
Will throw an exception if one of the following conditions occurs:
- The xpath does not in fact describe an existing property
- The property is not writable (no public, non-static set method)