/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-06 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.xquery.modules.math;
import org.apache.log4j.Logger;
import org.exist.dom.QName;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.DoubleValue;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* Class containing math functions that accept no parameters.
*
* @author Dannes Wessels
*/
public class NoParamFunctions extends BasicFunction {
private static final Logger logger = Logger.getLogger(NoParamFunctions.class);
public final static FunctionSignature signature[] = {
new FunctionSignature(
new QName("e", MathModule.NAMESPACE_URI),
"Returns base of the natural logarithms, e.",
null,
new FunctionReturnSequenceType(Type.DOUBLE, Cardinality.EXACTLY_ONE, "the value of e")
),
new FunctionSignature(
new QName("pi", MathModule.NAMESPACE_URI),
"Returns the value of pi.",
null,
new FunctionReturnSequenceType(Type.DOUBLE, Cardinality.EXACTLY_ONE, "the value of pi")
),
new FunctionSignature(
new QName("random", MathModule.NAMESPACE_URI),
"Returns a value greater than or equal to 0.0 and less than 1.0.",
null,
new FunctionReturnSequenceType(Type.DOUBLE, Cardinality.EXACTLY_ONE, "a random value")
)
};
/**
* @param context
*/
public NoParamFunctions(XQueryContext context, FunctionSignature signature) {
super(context, signature);
}
public int getDependencies() {
return Dependency.NO_DEPENDENCY;
}
/* (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[] args, Sequence contextSequence) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null){
context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);
}
}
Sequence result;
String functionName = getSignature().getName().getLocalName();
if("e".equals(functionName)) {
result=new DoubleValue(Math.E);
} else if("pi".equals(functionName)) {
result=new DoubleValue(Math.PI);
} else if("random".equals(functionName)) {
result=new DoubleValue(Math.random());
} else {
throw new XPathException(this, "Function "+functionName+" not found.");
}
if (context.getProfiler().isEnabled()){
context.getProfiler().end(this, "", result);
}
return result;
}
}