package client.net.sf.saxon.ce.functions;
import client.net.sf.saxon.ce.event.ComplexContentOutputter;
import client.net.sf.saxon.ce.event.SequenceReceiver;
import client.net.sf.saxon.ce.expr.XPathContext;
import client.net.sf.saxon.ce.tree.util.FastStringBuffer;
import client.net.sf.saxon.ce.om.Item;
import client.net.sf.saxon.ce.trans.XPathException;
import client.net.sf.saxon.ce.value.AtomicValue;
import client.net.sf.saxon.ce.value.SequenceType;
import client.net.sf.saxon.ce.value.StringValue;
public class Concat extends SystemFunction {
public Concat newInstance() {
return new Concat();
}
/**
* 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();
if (out instanceof ComplexContentOutputter) {
// This optimization is only safe if the output forms part of document or element content
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);
boolean empty = true;
for (int i=0; i<numArgs; i++) {
AtomicValue val = (AtomicValue)argument[i].evaluateItem(context);
if (val!=null) {
out.characters(val.getStringValueCS());
empty = false;
}
}
if (!empty) {
out.append(StringValue.EMPTY_STRING, 0);
}
} else {
out.append(evaluateItem(context), 0);
}
}
}
// 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.