package net.sf.saxon.functions;
import net.sf.saxon.event.SequenceReceiver;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.om.FastStringBuffer;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.SequenceType;
import net.sf.saxon.value.StringValue;
public class Concat extends SystemFunction {
/**
* Get the required type of the nth argument
*/
protected SequenceType getRequiredType(int arg) {
return getDetails().argumentTypes[0];
// concat() is a special case
}
/**
* Evaluate the function in a string context
*/
public CharSequence evaluateAsString(XPathContext c) throws XPathException {
return evaluateItem(c).getStringValueCS();
}
/**
* Evaluate in a general context
*/
public Item evaluateItem(XPathContext c) throws XPathException {
int numArgs = argument.length;
FastStringBuffer sb = new FastStringBuffer(FastStringBuffer.SMALL);
for (int i=0; i<numArgs; i++) {
AtomicValue val = (AtomicValue)argument[i].evaluateItem(c);
if (val!=null) {
sb.append(val.getStringValueCS());
}
}
return StringValue.makeStringValue(sb.condense());
}
/**
* Process the instruction in push mode. This avoids constructing the concatenated string
* in memory, instead each argument can be sent straight to the serializer.
* @param context The dynamic context, giving access to the current node,
* the current variables, etc.
*/
public void process(XPathContext context) throws XPathException {
SequenceReceiver out = context.getReceiver();
int numArgs = argument.length;
// Start and end with an empty string to force space separation from any previous or following outputs
out.append(StringValue.EMPTY_STRING, 0, 0);
boolean empty = true;
for (int i=0; i<numArgs; i++) {
AtomicValue val = (AtomicValue)argument[i].evaluateItem(context);
if (val!=null) {
out.characters(val.getStringValueCS(), 0, 0);
empty = false;
}
}
if (!empty) {
out.append(StringValue.EMPTY_STRING, 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.
//