/**
* 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();
}
/**
* Compile: this registers the template with the rule manager, and ensures space is available for
* local variables
*/
public Expression compile(Executable exec) throws XPathException {
Expression block = compileSequenceConstructor(exec, iterateAxis(Axis.CHILD), true);
if (block == null) {
block = Literal.makeEmptySequence();
}
compiledTemplate.setMatchPattern(match);
compiledTemplate.setBody(block);
compiledTemplate.setStackFrameMap(stackFrameMap);
compiledTemplate.setExecutable(getExecutable());
compiledTemplate.setSystemId(getSystemId());
compiledTemplate.setLineNumber(getLineNumber());
compiledTemplate.setHasRequiredParams(hasRequiredParams);
compiledTemplate.setRequiredType(requiredType);
Expression exp = null;
try {
exp = makeExpressionVisitor().simplify(block);
} catch (XPathException e) {
compileError(e);
}
try {
if (requiredType != null) {
RoleLocator role = new RoleLocator(RoleLocator.TEMPLATE_RESULT, diagnosticId, 0);
// role.setSourceLocator(new ExpressionLocation(this));
role.setErrorCode("XTTE0505");
exp = TypeChecker.staticTypeCheck(exp, requiredType, false, role, makeExpressionVisitor());
}
} catch (XPathException err) {
compileError(err);
}
compiledTemplate.setBody(exp);
compiledTemplate.init(getObjectName(), getPrecedence(), getMinImportPrecedence());
if (getConfiguration().isCompileWithTracing()) {
TraceWrapper trace = new TraceInstruction(exp, this);
trace.setLocationId(allocateLocationId(getSystemId(), getLineNumber()));
trace.setContainer(compiledTemplate);
exp = trace;
compiledTemplate.setBody(exp);
}
ItemType contextItemType = Type.ITEM_TYPE;
if (getObjectName() == null) {
// the template can't be called by name, so the context item must match the match pattern
contextItemType = match.getNodeTest();
}
ExpressionVisitor visitor = makeExpressionVisitor();
try {
// We've already done the typecheck of each XPath expression, but it's worth doing again at
// this
// level because we have more information now.
Expression exp2 = visitor.typeCheck(exp, contextItemType);
exp2 = visitor.optimize(exp2, contextItemType);
if (exp != exp2) {
compiledTemplate.setBody(exp2);
exp = exp2;
}
} catch (XPathException e) {
compileError(e);
}
// Try to extract new global variables from the body of the function
// ExpressionPresenter presenter = ExpressionPresenter.make(getConfiguration());
// exp.explain(presenter);
// presenter.close();
if (!getConfiguration().isCompileWithTracing()) {
Expression exp2 = getConfiguration().getOptimizer().promoteExpressionsToGlobal(exp, visitor);
if (exp != exp2) {
compiledTemplate.setBody(exp2);
exp = exp2;
}
}
allocateSlots(exp);
if (match != null) {
RuleManager mgr = getPrincipalStylesheet().getRuleManager();
for (int i = 0; i < modeNames.length; i++) {
StructuredQName nc = modeNames[i];
Mode mode = mgr.getMode(nc, true);
if (prioritySpecified) {
mgr.setHandler(match, compiledTemplate, mode, getPrecedence(), priority);
} else {
mgr.setHandler(match, compiledTemplate, mode, getPrecedence());
}
}
allocatePatternSlots(match, getSlotManager());
}
if (isExplaining()) {
System.err.println(
"Optimized expression tree for template at line "
+ getLineNumber()
+ " in "
+ getSystemId()
+ ':');
exp.explain(System.err);
}
return null;
}