package client.net.sf.saxon.ce.functions;
import client.net.sf.saxon.ce.expr.*;
import client.net.sf.saxon.ce.om.Item;
import client.net.sf.saxon.ce.value.Whitespace;
import client.net.sf.saxon.ce.trans.XPathException;
import client.net.sf.saxon.ce.type.ItemType;
import client.net.sf.saxon.ce.value.AtomicValue;
import client.net.sf.saxon.ce.value.StringValue;
import client.net.sf.saxon.ce.value.Value;
/**
* Implement the XPath normalize-space() function
*/
public class NormalizeSpace extends SystemFunction {
public NormalizeSpace newInstance() {
return new NormalizeSpace();
}
/**
* 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 client.net.sf.saxon.ce.value.StaticProperty
*/
public int getIntrinsicDependencies() {
int d = super.getIntrinsicDependencies();
if (argument.length == 0) {
d |= StaticProperty.DEPENDS_ON_CONTEXT_ITEM;
}
return d;
}
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
if (argument.length == 0 && contextItemType == null) {
typeError("The context item for normalize-space() is undefined", "XPDY0002", null);
}
return super.typeCheck(visitor, contextItemType);
}
/**
* 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
*/
public Expression preEvaluate(ExpressionVisitor visitor) throws XPathException {
if (argument.length == 0) {
return this;
} else {
return Literal.makeLiteral((Value)evaluateItem(
visitor.getStaticContext().makeEarlyEvaluationContext()));
}
}
/**
* Evaluate in a general context
*/
public Item evaluateItem(XPathContext c) throws XPathException {
if (argument.length == 0) {
Item item = c.getContextItem();
if (item == null) {
dynamicError("Context item for normalize-space() is undefined", "FONC0001", c);
return null;
}
return StringValue.makeStringValue(
Whitespace.collapseWhitespace(item.getStringValueCS()));
} else {
AtomicValue sv = (AtomicValue)argument[0].evaluateItem(c);
if (sv==null) {
return StringValue.EMPTY_STRING;
}
return StringValue.makeStringValue(
Whitespace.collapseWhitespace(sv.getStringValueCS()));
}
}
/**
* Get the effective boolean value of the expression. This returns false if the value
* is the empty sequence, a zero-length string, a number equal to zero, or the boolean
* false. Otherwise it returns true.
*
* <p>This method is implemented for normalize-space() because it is quite often used in a
* boolean context to test whether a value exists and is non-white, and because testing for the
* presence of non-white characters is a lot more efficient than constructing the normalized
* string, especially because of early-exit.</p>
*
* @param c The context in which the expression is to be evaluated
* @return the effective boolean value
* @throws client.net.sf.saxon.ce.trans.XPathException
* if any dynamic error occurs evaluating the expression
*/
public boolean effectiveBooleanValue(XPathContext c) throws XPathException {
CharSequence cs;
if (argument.length == 0) {
Item item = c.getContextItem();
if (item == null) {
dynamicError("Context item for normalize-space() is undefined", "FONC0001", c);
return false;
}
cs = item.getStringValueCS();
} else {
AtomicValue sv = (AtomicValue)argument[0].evaluateItem(c);
if (sv==null) {
return false;
}
cs = sv.getStringValueCS();
}
return !Whitespace.isWhite(cs);
}
}
// 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.