/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist.sourceforge.net
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery.modules.example;
import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
/**
* This is an example module showing how to create a function module.
*
* @author Wolfgang Meier (wolfgang@exist-db.org)
* @author Loren Cahlander (loren@syntactica.com)
*/
public class EchoFunction extends BasicFunction {
@SuppressWarnings("unused")
private final static Logger logger = Logger.getLogger(EchoFunction.class);
public final static FunctionSignature signature =
new FunctionSignature(
new QName("echo", ExampleModule.NAMESPACE_URI, ExampleModule.PREFIX),
"A useless example function. It just echoes the input parameters.",
new SequenceType[] { new FunctionParameterSequenceType("text", Type.STRING, Cardinality.ZERO_OR_MORE, "The text to echo")},
new FunctionReturnSequenceType(Type.STRING, Cardinality.ZERO_OR_MORE, "the echoed text"));
public EchoFunction(XQueryContext context) {
super(context, signature);
}
public Sequence eval(Sequence[] args, Sequence contextSequence)
throws XPathException {
// is argument the empty sequence?
if (args[0].isEmpty()) {
return Sequence.EMPTY_SEQUENCE;
}
// iterate through the argument sequence and echo each item
ValueSequence result = new ValueSequence();
for (SequenceIterator i = args[0].iterate(); i.hasNext();) {
String str = i.nextItem().getStringValue();
result.add(new StringValue("echo: " + str));
}
return result;
}
}