/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 The eXist Project
* http://exist-db.org
*
* 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.functions.util;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.xquery.AnalyzeContextInfo;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Expression;
import org.exist.xquery.Function;
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.FunctionReference;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* @author wolf
*/
public class CallFunction extends Function {
protected static final Logger logger = Logger.getLogger(CallFunction.class);
public final static FunctionSignature signature =
new FunctionSignature(
new QName("call", UtilModule.NAMESPACE_URI, UtilModule.PREFIX),
"Invokes a first-class function reference created by util:function. The function " +
"to be called is passed as the first argument. All remaining arguments are " +
"forwarded to the called function.",
new SequenceType[] {
new FunctionParameterSequenceType("function-reference", Type.FUNCTION_REFERENCE, Cardinality.EXACTLY_ONE, "The function to ba called"),
new FunctionParameterSequenceType("parameters", Type.ITEM, Cardinality.ZERO_OR_MORE, "The parameters to be passed into the function")
},
new FunctionReturnSequenceType(Type.ITEM, Cardinality.ZERO_OR_MORE, "the results from the function called"),
true
);
/**
* @param context
*/
public CallFunction(XQueryContext context) {
super(context, signature);
}
/* (non-Javadoc)
* @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
*/
public Sequence eval(Sequence contextSequence, Item contextItem)
throws XPathException {
final Sequence arg0 = getArgument(0).eval(contextSequence, contextItem);
if(arg0.getCardinality() != Cardinality.EXACTLY_ONE)
{throw new XPathException(this, "Expected exactly one item for first argument");}
final Item item0 = arg0.itemAt(0);
if(item0.getType() != Type.FUNCTION_REFERENCE)
{throw new XPathException(this, "Type error: expected function, got " + Type.getTypeName(item0.getType()));}
final FunctionReference ref = (FunctionReference)item0;
// pass the remaining parameters to the function call
final List<Expression> params = new ArrayList<Expression>(getArgumentCount() - 1);
for(int i = 1; i < getArgumentCount(); i++) {
params.add(getArgument(i));
}
ref.setArguments(params);
ref.analyze(new AnalyzeContextInfo(this, 0));
// Evaluate the function
return ref.eval(contextSequence);
}
}