/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.sparql.expr.aggregate;
import org.apache.jena.atlas.logging.Log ;
import org.apache.jena.graph.Node ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.expr.Expr ;
import org.apache.jena.sparql.expr.ExprList ;
import org.apache.jena.sparql.expr.NodeValue ;
import org.apache.jena.sparql.function.FunctionEnv ;
import org.apache.jena.sparql.graph.NodeConst ;
import org.apache.jena.sparql.serializer.SerializationContext ;
public class AggCount extends AggregatorBase
{
// ---- COUNT(*)
public AggCount() { super("COUNT", false, (ExprList)null) ; }
@Override
public Aggregator copy(ExprList expr)
{
if ( expr != null )
Log.warn(this, "Copying non-null expression for COUNT(*)") ;
return new AggCount() ; }
@Override
public Expr getExpr() { return null ; }
@Override
public Accumulator createAccumulator()
{
return new AggCount.AccCount();
}
@Override
public String asSparqlExpr(SerializationContext sCxt) { return "count(*)" ; }
@Override
public String toString() { return "count(*)" ; }
@Override
public String toPrefixString() { return "(count)" ; }
@Override
public Node getValueEmpty() { return NodeConst.nodeZero ; }
@Override
public int hashCode() { return HC_AggCount ; }
@Override
public boolean equals(Aggregator other, boolean bySyntax) {
if ( other == null ) return false ;
if ( this == other ) return true ;
if ( ! ( other instanceof AggCount ) ) return false ;
return true ;
}
static class AccCount implements Accumulator
{
private long count = 0 ;
public AccCount() { }
@Override
public void accumulate(Binding binding, FunctionEnv functionEnv)
{ count++ ; }
// Errors can't occur.
@Override
public NodeValue getValue() { return NodeValue.makeInteger(count) ; }
}
}