/**
* Set the local stack frame. This method is used when creating a Closure to support delayed
* evaluation of expressions. The "stack frame" is actually on the Java heap, which means it can
* survive function returns and the like.
*/
public void setStackFrame(SlotManager map, ValueRepresentation[] variables) {
stackFrame = new StackFrame(map, variables);
if (map != null && variables.length != map.getNumberOfVariables()) {
stackFrame.slots = new ValueRepresentation[map.getNumberOfVariables()];
System.arraycopy(variables, 0, stackFrame.slots, 0, variables.length);
}
}
/**
* Declare a variable. A variable may be declared before an expression referring to it is
* compiled. Alternatively, a JAXP XPathVariableResolver may be supplied to perform the
* resolution. A variable that has been explicitly declared is used in preference.
*
* @param qname Lexical QName identifying the variable. The namespace prefix, if any, must have
* been declared before this method is called, or must be resolvable using the namespace
* context.
* @param initialValue The initial value of the variable. A Java object that can be converted to
* an XPath value.
*/
public Variable declareVariable(String qname, Object initialValue) throws XPathException {
String prefix;
String localName;
try {
String[] parts = Name.getQNameParts(qname);
prefix = parts[0];
localName = parts[1];
} catch (QNameException err) {
throw new StaticError("Invalid QName for variable: " + qname);
}
String uri = "";
if (!("".equals(prefix))) {
uri = getURIForPrefix(prefix);
}
Variable var = Variable.make(qname, getConfiguration());
var.setValue(initialValue);
int fingerprint = namePool.allocate(prefix, uri, localName) & 0xfffff;
variables.put(new Integer(fingerprint), var);
stackFrameMap.allocateSlotNumber(fingerprint);
return var;
}
/**
* Create a new stack frame for local variables, using the supplied SlotManager to define the
* allocation of slots to individual variables
*
* @param map the SlotManager for the new stack frame
*/
public void openStackFrame(SlotManager map) {
stackFrame = new StackFrame(map, new ValueRepresentation[map.getNumberOfVariables()]);
}