package client.net.sf.saxon.ce.trace;
import java.util.Iterator;
import client.net.sf.saxon.ce.expr.UserFunctionCall;
import client.net.sf.saxon.ce.expr.XPathContext;
import client.net.sf.saxon.ce.expr.XPathContextMajor;
import client.net.sf.saxon.ce.expr.instruct.ApplyTemplates;
import client.net.sf.saxon.ce.expr.instruct.CallTemplate;
import client.net.sf.saxon.ce.expr.instruct.GeneralVariable;
import client.net.sf.saxon.ce.om.StandardNames;
/**
* This class provides a representation of the current runtime call stack, as represented by the stack
* of XPathContext objects.
*/
public class ContextStackIterator implements Iterator<ContextStackFrame> {
private XPathContextMajor next;
/**
* Create an iterator over the stack of XPath dynamic context objects, starting with the top-most
* stackframe and working down. The objects returned by this iterator will be of class {@link ContextStackFrame}.
* Note that only "major" context objects are considered - those that have a stack frame of their own.
* @param context the current context
*/
public ContextStackIterator(XPathContext context) {
if (!(context instanceof XPathContextMajor)) {
context = getMajorCaller(context);
}
next = (XPathContextMajor)context;
}
/**
* Returns <tt>true</tt> if the iteration has more elements. (In other
* words, returns <tt>true</tt> if <tt>next</tt> would return an element
* rather than throwing an exception.)
*
* @return <tt>true</tt> if the iterator has more elements.
*/
public boolean hasNext() {
return next != null;
}
/**
* Returns the next element in the iteration. Calling this method
* repeatedly until the {@link #hasNext()} method returns false will
* return each element in the underlying collection exactly once.
*
* @return the next element in the iteration, which will always be an instance
* of {@link ContextStackFrame}
* @throws java.util.NoSuchElementException
* iteration has no more elements.
*/
/*@Nullable*/ public ContextStackFrame next() {
XPathContextMajor context = next;
if (context == null) {
return null;
}
int construct = context.getOriginatingConstructType();
Object origin = context.getOrigin();
if (construct == Location.CONTROLLER) {
next = getMajorCaller(context);
return new ContextStackFrame.CallingApplication();
} else if (construct == Location.BUILT_IN_TEMPLATE) {
next = getMajorCaller(context);
return new ContextStackFrame.BuiltInTemplateRule();
}
if (construct == Location.FUNCTION_CALL) {
ContextStackFrame.FunctionCall sf = new ContextStackFrame.FunctionCall();
UserFunctionCall ufc = (UserFunctionCall)origin;
sf.setSystemId(ufc.getSystemId());
sf.setLineNumber(-1); //(ufc.getLineNumber());
sf.setContainer(ufc.getContainer());
sf.setFunctionName(ufc.getFunctionName());
sf.setContextItem(context.getContextItem());
next = getMajorCaller(context);
return sf;
} else if (construct == StandardNames.XSL_APPLY_TEMPLATES) {
ContextStackFrame.ApplyTemplates sf = new ContextStackFrame.ApplyTemplates();
ApplyTemplates loc = (ApplyTemplates)origin;
sf.setSystemId(loc.getSystemId());
sf.setLineNumber(-1); //(loc.getLineNumber());
sf.setContainer(loc.getContainer());
sf.setContextItem(context.getContextItem());
next = getMajorCaller(context);
return sf;
} else if (construct == StandardNames.XSL_CALL_TEMPLATE) {
ContextStackFrame.CallTemplate sf = new ContextStackFrame.CallTemplate();
CallTemplate loc = (CallTemplate)origin;
sf.setSystemId(loc.getSystemId());
sf.setLineNumber(-1); //(loc.getLineNumber());
sf.setContainer(loc.getContainer());
sf.setTemplateName(loc.getObjectName());
sf.setContextItem(context.getContextItem());
next = getMajorCaller(context);
return sf;
} else if (construct == StandardNames.XSL_VARIABLE) {
ContextStackFrame.VariableEvaluation sf = new ContextStackFrame.VariableEvaluation();
GeneralVariable var = ((GeneralVariable)origin);
sf.setSystemId(var.getSystemId());
sf.setLineNumber(-1); //(var.getLineNumber());
sf.setContainer(var.getContainer());
sf.setContextItem(context.getContextItem());
sf.setVariableName(var.getVariableQName());
next = getMajorCaller(context);
return sf;
} else {
//other context changes are not considered significant enough to report
//out.println(" In unidentified location " + construct);
next = getMajorCaller(context);
ContextStackFrame csf = next();
if (csf == null) {
// we can't return null, because hasNext() returned true...
return new ContextStackFrame.CallingApplication();
} else {
return csf;
}
}
}
private static XPathContextMajor getMajorCaller(XPathContext context) {
XPathContext caller = context.getCaller();
while (!(caller == null || caller instanceof XPathContextMajor)) {
caller = caller.getCaller();
}
return (XPathContextMajor)caller;
}
/**
* Removes from the underlying collection the last element returned by the
* iterator (optional operation).
*
* @throws UnsupportedOperationException as the <tt>remove</tt>
* operation is not supported by this Iterator.
*/
public void remove() {
throw new UnsupportedOperationException();
}
}
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is “Incompatible With Secondary Licenses”, as defined by the Mozilla Public License, v. 2.0.