/*
* 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.functions.util;
import java.util.Iterator;
import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.memtree.DocumentImpl;
import org.exist.memtree.MemTreeBuilder;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Module;
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.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.xml.sax.helpers.AttributesImpl;
/**
* Describe a built-in function identified by its QName.
*
* @author wolf
*/
public class DescribeFunction extends Function {
protected static final Logger logger = Logger.getLogger(DescribeFunction.class);
public final static FunctionSignature signature =
new FunctionSignature(
new QName("describe-function", UtilModule.NAMESPACE_URI, UtilModule.PREFIX),
"Describes a built-in function. Returns an element describing the " +
"function signature.",
new SequenceType[] {
new FunctionParameterSequenceType("function-name", Type.QNAME, Cardinality.EXACTLY_ONE, "The name of the function to get the signature of"),
},
new FunctionReturnSequenceType(Type.NODE, Cardinality.EXACTLY_ONE, "the signature of the function"));
public DescribeFunction(XQueryContext context) {
super(context, signature);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval(
Sequence contextSequence,
Item contextItem)
throws XPathException {
String fname = getArgument(0).eval(contextSequence, contextItem).getStringValue();
QName qname = QName.parse(context, fname, context.getDefaultFunctionNamespace());
String uri = qname.getNamespaceURI();
MemTreeBuilder builder = context.getDocumentBuilder();
AttributesImpl attribs = new AttributesImpl();
attribs.addAttribute("", "name", "name", "CDATA", qname.getStringValue());
attribs.addAttribute("", "module", "module", "CDATA", uri);
int nodeNr = builder.startElement("", "function", "function", attribs);
FunctionSignature signature;
Module module = context.getModule(uri);
if(module != null) {
Iterator i = module.getSignaturesForFunction(qname);
while(i.hasNext()) {
signature = (FunctionSignature) i.next();
writeSignature(signature, builder);
}
} else {
Iterator i = context.getSignaturesForFunction(qname);
while(i.hasNext()) {
signature = (FunctionSignature) i.next();
writeSignature(signature, builder);
}
}
builder.endElement();
return ((DocumentImpl)builder.getDocument()).getNode(nodeNr);
}
/**
* @param signature
* @param builder
* @param attribs
*/
private void writeSignature(FunctionSignature signature, MemTreeBuilder builder) {
AttributesImpl attribs = new AttributesImpl();
attribs.addAttribute("", "arguments", "arguments", "CDATA", Integer.toString(signature.getArgumentCount()));
builder.startElement("", "prototype", "prototype", attribs);
attribs.clear();
builder.startElement("", "signature", "signature", attribs);
builder.characters(signature.toString());
builder.endElement();
if(signature.getDescription() != null) {
builder.startElement("", "description", "description", attribs);
StringBuilder description = new StringBuilder();
description.append(signature.getDescription());
description.append("\n\n");
SequenceType argumentTypes[] = signature.getArgumentTypes();
if(argumentTypes != null && argumentTypes.length>0){
StringBuilder args = new StringBuilder();
int noArgs=0;
for (SequenceType argumentType : argumentTypes) {
if (argumentType instanceof FunctionParameterSequenceType) {
noArgs++;
FunctionParameterSequenceType fp
= (FunctionParameterSequenceType) argumentType;
args.append("$");
args.append(fp.getAttributeName());
args.append(" : ");
args.append(fp.getDescription());
args.append("\n");
}
}
// only add if there were good arguments
if(noArgs>0){
description.append("Parameters:\n");
description.append(args);
}
}
SequenceType returnType = signature.getReturnType();
if(returnType != null){
if (returnType instanceof FunctionReturnSequenceType) {
description.append("\n");
description.append("Returns ");
FunctionReturnSequenceType fp
= (FunctionReturnSequenceType) returnType;
description.append(fp.getDescription());
description.append("\n");
}
}
builder.characters(description.toString());
builder.endElement();
}
if (signature.getDeprecated() != null) {
builder.startElement("", "deprecated", "deprecated", attribs);
builder.characters(signature.getDeprecated());
builder.endElement();
}
builder.endElement();
}
}