package net.sf.saxon.functions;
import net.sf.saxon.event.SequenceOutputter;
import net.sf.saxon.event.SequenceReceiver;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.ExpressionVisitor;
import net.sf.saxon.expr.PathMap;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.instruct.DivisibleInstruction;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.value.StringValue;
import java.util.Stack;
/**
* Implement XPath function string()
*/
public class StringFn extends SystemFunction implements DivisibleInstruction {
/**
* Simplify and validate.
* This is a pure function so it can be simplified in advance if the arguments are known
* @param visitor an expression visitor
*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
useContextItemAsDefault();
argument[0].setFlattened(true);
return simplifyArguments(visitor);
}
/**
* Add a representation of a doc() call or similar function to a PathMap.
* This is a convenience method called by the addToPathMap() methods for doc(), document(), collection()
* and similar functions. These all create a new root expression in the path map.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodes the node in the PathMap representing the focus at the point where this expression
* is called. Set to null if this expression appears at the top level.
* @return the pathMapNode representing the focus established by this expression, in the case where this
* expression is the first operand of a path expression or filter expression
*/
public PathMap.PathMapNodeSet addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes) {
PathMap.PathMapNodeSet result = argument[0].addToPathMap(pathMap, pathMapNodes);
if (result != null) {
result.setAtomized();
}
return null;
}
/**
* Evaluate the function
*/
public Item evaluateItem(XPathContext c) throws XPathException {
try {
Item arg = argument[0].evaluateItem(c);
if (arg==null) {
return StringValue.EMPTY_STRING;
} else if (arg instanceof StringValue && ((StringValue)arg).getTypeLabel() == BuiltInAtomicType.STRING) {
return arg;
} else {
return StringValue.makeStringValue(arg.getStringValueCS());
}
} catch (UnsupportedOperationException e) {
// Cannot obtain the string value of a function item
XPathException err = new XPathException(e.getMessage(), "FOTY0014");
err.setLocator(this);
err.setXPathContext(c);
throw err;
}
}
/**
* In streaming mode, process the first half of the instruction (for example, to start a new document or element)
* @param contextStack
* @param state a stack on which the instruction can save state information during the call on processLeft()
*/
public void processLeft(Stack<XPathContext> contextStack, Stack state) throws XPathException {
XPathContext context = contextStack.peek();
SequenceReceiver out = context.getReceiver();
state.push(out);
SequenceOutputter out2 = new SequenceOutputter();
out2.setPipelineConfiguration(out.getPipelineConfiguration());
context.setReceiver(out2);
}
/**
* In streaming mode, process the right half of the instruction (for example, to end a new document or element)
* Note that unlike other divisible instructions this one doesn't push the result to the current output
* destination, it leaves a sequenceIterator over the result on the stack.
* @param contextStack
* @param state a stack on which the instruction can save state information during the call on processLeft()
*/
public void processRight(Stack<XPathContext> contextStack, Stack state) throws XPathException {
XPathContext context = contextStack.peek();
CharSequence value = ((SequenceOutputter)context.getReceiver()).getFirstItem().getStringValueCS();
SequenceReceiver out = (SequenceReceiver)state.pop();
context.setReceiver(out);
out.append(new StringValue(value), 0, 0);
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//