package net.sf.saxon.functions;
import net.sf.saxon.expr.*;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.Int64Value;
import net.sf.saxon.value.StringValue;
import net.sf.saxon.value.Value;
/**
* Implement the XPath string-length() function
*/
public class StringLength extends SystemFunction {
/**
* 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();
return simplifyArguments(visitor);
}
/**
* Determine the intrinsic dependencies of an expression, that is, those which are not derived
* from the dependencies of its subexpressions. For example, position() has an intrinsic dependency
* on the context position, while (position()+1) does not. The default implementation
* of the method returns 0, indicating "no dependencies".
*
* @return a set of bit-significant flags identifying the "intrinsic"
* dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
*/
public int getIntrinsicDependencies() {
int d = super.getIntrinsicDependencies();
if (argument.length == 0) {
d |= StaticProperty.DEPENDS_ON_CONTEXT_ITEM;
}
return d;
}
/**
* Pre-evaluate a function at compile time. Functions that do not allow
* pre-evaluation, or that need access to context information, can override this method.
* @param visitor an expression visitor
* @return the expression, either unchanged, or pre-evaluated
*/
public Expression preEvaluate(ExpressionVisitor visitor) throws XPathException {
if (argument.length == 0) {
return this;
} else {
return Literal.makeLiteral(
(Value)evaluateItem(visitor.getStaticContext().makeEarlyEvaluationContext()));
}
}
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
if (argument.length == 0 && contextItemType == null) {
XPathException err = new XPathException("The context item for string-length() is undefined");
err.setErrorCode("XPDY0002");
err.setIsTypeError(true);
err.setLocator(this);
throw err;
}
return super.typeCheck(visitor, contextItemType);
}
/**
* Evaluate in a general context
*/
public Item evaluateItem(XPathContext c) throws XPathException {
AtomicValue sv;
if (argument.length == 0) {
final Item contextItem = c.getContextItem();
if (contextItem == null) {
dynamicError("The context item for string-length() is not set", "XPDY0002", c);
return null;
}
sv = StringValue.makeStringValue(contextItem.getStringValueCS());
} else {
sv = (AtomicValue)argument[0].evaluateItem(c);
}
if (sv==null) {
return Int64Value.ZERO;
}
if (sv instanceof StringValue) {
return Int64Value.makeIntegerValue(((StringValue)sv).getStringLength());
} else {
CharSequence s = sv.getStringValueCS();
return Int64Value.makeIntegerValue(StringValue.getStringLength(s));
}
}
}
//
// 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.
//