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java.lang.Object net.sf.saxon.query.XQueryExpression
public class XQueryExpression
XQueryExpression represents a compiled query. This object is immutable and thread-safe, the same compiled query may be executed many times in series or in parallel. The object can be created only by using the compileQuery method of the QueryProcessor class.
Various methods are provided for evaluating the query, with different options for delivery of the results.
Constructor Summary | |
---|---|
protected |
XQueryExpression(Expression exp,
Executable exec,
QueryModule mainModule,
Configuration config)
The constructor is protected, to ensure that instances can only be created using the compileQuery() methods of StaticQueryContext |
Method Summary | |
---|---|
List |
evaluate(DynamicQueryContext env)
Execute a the compiled Query, returning the results as a List. |
Object |
evaluateSingle(DynamicQueryContext env)
Execute the compiled Query, returning the first item in the result. |
void |
explain(ExpressionPresenter out)
Diagnostic method: display a representation of the compiled query on the selected output stream. |
int |
getColumnNumber()
Return the character position where the current document event ends. |
int |
getContainerGranularity()
Get the granularity of the container. |
Executable |
getExecutable()
Get the Executable (representing a complete stylesheet or query) of which this Container forms part |
Expression |
getExpression()
Get the expression wrapped in this XQueryExpression object |
StructuredQName[] |
getExternalVariableNames()
Get a list containing the names of the external variables in the query. |
int |
getHostLanguage()
Get the host language (XSLT, XQuery, XPath) used to implement the code in this container |
int |
getLineNumber()
Return the line number where the current document event ends. |
LocationProvider |
getLocationProvider()
Get the LocationProvider allowing location identifiers to be resolved. |
PathMap |
getPathMap()
Get the path map for the query expression |
String |
getPublicId()
Return the public identifier for the current document event. |
SlotManager |
getStackFrameMap()
Get the stack frame map used for the outermost level of this query |
QueryModule |
getStaticContext()
Get the static context in which this expression was compiled. |
String |
getSystemId()
Return the system identifier for the current document event. |
boolean |
isDocumentProjectionAllowed()
Ask whether document projection is allowed |
boolean |
isUpdateQuery()
Ask whether this is an update query |
EventIterator |
iterateEvents(Controller controller,
DynamicQueryContext dynamicEnv)
Run the query returning the results as an EventIterator |
SequenceIterator |
iterator(DynamicQueryContext env)
Get an iterator over the results of the expression. |
Controller |
newController()
Get a controller that can be used to execute functions in this compiled query. |
void |
pull(DynamicQueryContext dynamicEnv,
Result destination,
Properties outputProperties)
Run the query in pull mode. |
void |
run(DynamicQueryContext env,
Result result,
Properties outputProperties)
Run the query, sending the results directly to a JAXP Result object. |
Set |
runUpdate(DynamicQueryContext dynamicEnv)
Run an updating query |
void |
runUpdate(DynamicQueryContext dynamicEnv,
UpdateAgent agent)
Run an updating query, writing back eligible updated node to persistent storage. |
void |
setAllowDocumentProjection(boolean allowed)
Indicate that document projection is or is not allowed |
boolean |
usesContextItem()
Ask whether this query uses the context item |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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protected XQueryExpression(Expression exp, Executable exec, QueryModule mainModule, Configuration config) throws XPathException
exp
- an expression to be wrapped as an XQueryExpressionexec
- the executablemainModule
- the static context of the main moduleconfig
- the configuration
XPathException
- if an error occursMethod Detail |
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public Expression getExpression()
public int getContainerGranularity()
getContainerGranularity
in interface Container
public boolean usesContextItem()
public boolean isUpdateQuery()
public SlotManager getStackFrameMap()
public QueryModule getStaticContext()
public StructuredQName[] getExternalVariableNames()
Changed in Saxon 9.0 to return an array of StructuredQName objects rather than integer fingerprints.
public List evaluate(DynamicQueryContext env) throws XPathException
env
- Provides the dynamic query evaluation context
evaluate
method
of class XPathProcessor
XPathException
public Object evaluateSingle(DynamicQueryContext env) throws XPathException
env
- Provides the dynamic query evaluation context
evaluate
method
XPathException
public SequenceIterator iterator(DynamicQueryContext env) throws XPathException
To get the results of the query in the form of an XML document in which each item is wrapped by an element indicating its type, use:
QueryResult.wrap(iterator(env))
To serialize the results to a file, use the QueryResult.serialize() method.
env
- Provides the dynamic query evaluation context
XPathException
- if a dynamic error occurs in evaluating the query. Some
dynamic errors will not be reported by this method, but will only be reported
when the individual items of the result are accessed using the returned iterator.public void run(DynamicQueryContext env, Result result, Properties outputProperties) throws XPathException
env
- the dynamic query contextresult
- the destination for the results of the query. The query is effectively wrapped
in a document{} constructor, so that the items in the result are concatenated to form a single
document; this is then written to the requested Result destination, which may be (for example)
a DOMResult, a SAXResult, or a StreamResultoutputProperties
- Supplies serialization properties, in JAXP format, if the result is to
be serialized. This parameter can be defaulted to null.
XPathException
- if the query fails.public void pull(DynamicQueryContext dynamicEnv, Result destination, Properties outputProperties) throws XPathException
For maximum effect this method should be used when lazyConstructionMode has been set in the Configuration.
Note: this method usually has very similar performance to the
run(DynamicQueryContext,javax.xml.transform.Result,java.util.Properties)
method (which does
the same thing), but sometimes it is significantly slower. Therefore, the run() method is preferred.
dynamicEnv
- the dynamic context for query evaluationdestination
- the destination of the query resultsoutputProperties
- the serialization parameters
XPathException
Configuration.setLazyConstructionMode(boolean)
public EventIterator iterateEvents(Controller controller, DynamicQueryContext dynamicEnv) throws XPathException
controller
- The Controller used to run the querydynamicEnv
- the XQuery dynamic context for evaluating the query
XPathException
public Set runUpdate(DynamicQueryContext dynamicEnv) throws XPathException
dynamicEnv
- the dynamic context for query execution
On completion of this method it is generally unsafe to rely on the contents or relationships of NodeInfo objects that were obtained before the updating query was run. Such objects may or may not reflect the results of the update operations. This is especially true in the case of nodes that are part of a subtree that has been deleted (detached from its parent). Instead, the new updated tree should be accessed by navigation from the root nodes returned by this method.
XPathException
- if evaluation of the update query fails, or it this is not an updating querypublic void runUpdate(DynamicQueryContext dynamicEnv, UpdateAgent agent) throws XPathException
A node is eligible to be written back to disk if it is present in the document pool, which generally means that it was originally read using the doc() or collection() function.
On completion of this method it is generally unsafe to rely on the contents or relationships of NodeInfo objects that were obtained before the updating query was run. Such objects may or may not reflect the results of the update operations. This is especially true in the case of nodes that are part of a subtree that has been deleted (detached from its parent). Instead, the new updated tree should be accessed by navigation from the root nodes returned by this method.
If one or more eligible updated nodes cannot be written back to disk, perhaps because the URI identifies a non-updatable location, then an exception is thrown. In this case it is undefined
dynamicEnv
- the dynamic context for query execution
XPathException
- if evaluation of the update query fails, or it this is not an updating querypublic Controller newController()
QueryModule.getUserDefinedFunction(java.lang.String, java.lang.String, int)
.
They can then be called directly from the Java application using UserFunction.call(net.sf.saxon.om.ValueRepresentation[], net.sf.saxon.expr.XPathContextMajor)
The same Controller can be used for a series of function calls. Note that the Controller should only be used
in a single thread.
public void explain(ExpressionPresenter out)
out
- an ExpressionPresenter to which the XML representation of the compiled query
will be sentpublic Executable getExecutable()
getExecutable
in interface Container
public PathMap getPathMap()
public LocationProvider getLocationProvider()
getLocationProvider
in interface Container
public void setAllowDocumentProjection(boolean allowed)
allowed
- true if projection is allowedpublic boolean isDocumentProjectionAllowed()
public String getPublicId()
The return value is the public identifier of the document entity or of the external parsed entity in which the markup that triggered the event appears.
getPublicId
in interface SourceLocator
getSystemId()
public String getSystemId()
The return value is the system identifier of the document entity or of the external parsed entity in which the markup that triggered the event appears.
If the system identifier is a URL, the parser must resolve it fully before passing it to the application.
getSystemId
in interface SourceLocator
getPublicId()
public int getLineNumber()
Warning: The return value from the method is intended only as an approximation for the sake of error reporting; it is not intended to provide sufficient information to edit the character content of the original XML document.
The return value is an approximation of the line number in the document entity or external parsed entity where the markup that triggered the event appears.
getLineNumber
in interface SourceLocator
getColumnNumber()
public int getColumnNumber()
Warning: The return value from the method is intended only as an approximation for the sake of error reporting; it is not intended to provide sufficient information to edit the character content of the original XML document.
The return value is an approximation of the column number in the document entity or external parsed entity where the markup that triggered the event appears.
getColumnNumber
in interface SourceLocator
getLineNumber()
public int getHostLanguage()
getHostLanguage
in interface Container
Configuration.XSLT
or Configuration.XQUERY
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