/**
* The constructor is protected, to ensure that instances can only be created using the
* compileQuery() methods of StaticQueryContext
*
* @param exp an expression to be wrapped as an XQueryExpression
* @param exec the executable
* @param mainModule the static context of the main module
* @param config the configuration
* @throws XPathException if an error occurs
*/
protected XQueryExpression(
Expression exp, Executable exec, QueryModule mainModule, Configuration config)
throws XPathException {
stackFrameMap = config.makeSlotManager();
executable = exec;
exp.setContainer(this);
try {
ExpressionVisitor visitor = ExpressionVisitor.make(mainModule);
visitor.setExecutable(exec);
exp = visitor.simplify(exp);
exp.checkForUpdatingSubexpressions();
exp = visitor.typeCheck(exp, mainModule.getUserQueryContext().getRequiredContextItemType());
// ExpressionPresenter presenter = new ExpressionPresenter(config,
// ExpressionPresenter.defaultDestination(config, new
// FileOutputStream("c:/projects/montreal/before50.xml")));
// exp.explain(presenter);
// presenter.close();
exp = exp.optimize(visitor, Type.ITEM_TYPE);
} catch (XPathException err) {
// err.printStackTrace();
mainModule.reportFatalError(err);
throw err;
}
ExpressionTool.allocateSlots(exp, 0, stackFrameMap);
expression = exp;
executable.setConfiguration(config);
executable.setDefaultCollationName(mainModule.getDefaultCollationName());
executable.setCollationTable(mainModule.getUserQueryContext().getAllCollations());
staticContext = mainModule;
isUpdating = exp.isUpdatingExpression();
}
/**
* Diagnostic method: display a representation of the compiled query on the selected output
* stream.
*
* @param out an ExpressionPresenter to which the XML representation of the compiled query will be
* sent
*/
public void explain(ExpressionPresenter out) {
out.startElement("query");
staticContext.getExecutable().getKeyManager().explainKeys(out);
staticContext.getExecutable().explainGlobalVariables(out);
staticContext.explainGlobalFunctions(out);
out.startElement("body");
expression.explain(out);
out.endElement();
out.endElement();
out.close();
}
/**
* Run an updating query, writing back eligible updated node to persistent storage.
*
* <p>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.
*
* <p>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.
*
* <p>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
*
* @param dynamicEnv the dynamic context for query execution
* @throws XPathException if evaluation of the update query fails, or it this is not an updating
* query
*/
public void runUpdate(DynamicQueryContext dynamicEnv, UpdateAgent agent) throws XPathException {
if (!isUpdating) {
throw new XPathException("Calling runUpdate() on a non-updating query");
}
Configuration config = executable.getConfiguration();
Controller controller = newController();
initializeController(dynamicEnv, controller);
XPathContextMajor context = initialContext(dynamicEnv, controller);
try {
PendingUpdateList pul = config.newPendingUpdateList();
context.openStackFrame(stackFrameMap);
expression.evaluatePendingUpdates(context, pul);
pul.apply(context, staticContext.getRevalidationMode());
for (Iterator iter = pul.getAffectedTrees().iterator(); iter.hasNext(); ) {
NodeInfo node = (NodeInfo) iter.next();
agent.update(node, controller);
}
} catch (XPathException e) {
if (!e.hasBeenReported()) {
try {
controller.getErrorListener().fatalError(e);
} catch (TransformerException e2) {
// ignore secondary error
}
}
throw e;
}
}
/**
* Get an iterator over the results of the expression. This returns results without any conversion
* of the returned items to "native" Java classes. The iterator will deliver a sequence of Item
* objects, each item being either a NodeInfo (representing a node) or an AtomicValue
* (representing an atomic value).
*
* <p>
*
* <p>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:
*
* <p>
*
* <p><code>QueryResult.wrap(iterator(env))</code>
*
* <p>
*
* <p>To serialize the results to a file, use the QueryResult.serialize() method.
*
* @param env Provides the dynamic query evaluation context
* @return an iterator over the results of the query. The class SequenceIterator is modeled on the
* standard Java Iterator class, but has extra functionality and can throw exceptions when
* errors occur.
* @throws 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 SequenceIterator iterator(DynamicQueryContext env) throws XPathException {
if (isUpdating) {
throw new XPathException("Cannot call iterator() on an updating query");
}
Controller controller = newController();
initializeController(env, controller);
try {
Item contextItem = env.getContextItem();
// Bindery bindery = controller.getBindery();
// bindery.openStackFrame();
controller.defineGlobalParameters();
XPathContextMajor context = controller.newXPathContext();
if (contextItem != null) {
if (!staticContext
.getUserQueryContext()
.getRequiredContextItemType()
.matchesItem(contextItem, false, env.getConfiguration())) {
throw new XPathException(
"The supplied context item does not match the required context item type");
}
UnfailingIterator single = SingletonIterator.makeIterator(contextItem);
single.next();
context.setCurrentIterator(single);
controller.setInitialContextItem(contextItem);
}
// In tracing/debugging mode, evaluate all the global variables first
if (controller.getTraceListener() != null) {
controller.preEvaluateGlobals(context);
}
context.openStackFrame(stackFrameMap);
SequenceIterator iterator = expression.iterate(context);
return new ErrorReportingIterator(iterator, controller.getErrorListener());
} catch (XPathException err) {
TransformerException terr = err;
while (terr.getException() instanceof TransformerException) {
terr = (TransformerException) terr.getException();
}
XPathException de = XPathException.makeXPathException(terr);
controller.reportFatalError(de);
throw de;
}
}
private XPathContextMajor initialContext(DynamicQueryContext dynamicEnv, Controller controller)
throws XPathException {
Item contextItem = dynamicEnv.getContextItem();
controller.defineGlobalParameters();
XPathContextMajor context = controller.newXPathContext();
if (contextItem != null) {
if (!staticContext
.getUserQueryContext()
.getRequiredContextItemType()
.matchesItem(contextItem, false, dynamicEnv.getConfiguration())) {
throw new XPathException(
"The supplied context item does not match the required context item type");
}
UnfailingIterator single = SingletonIterator.makeIterator(contextItem);
single.next();
context.setCurrentIterator(single);
controller.setInitialContextItem(contextItem);
}
return context;
}
