/*
* 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 com.hp.hpl.jena.sparql.expr;
import org.apache.jena.atlas.lib.Lib ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.function.FunctionEnv ;
import com.hp.hpl.jena.sparql.function.FunctionEnvBase ;
import com.hp.hpl.jena.sparql.graph.NodeTransform ;
/** A function that has a single argument */
public abstract class ExprFunction1 extends ExprFunction
{
protected final Expr expr ;
protected ExprFunction1(Expr expr, String fName) { this(expr, fName, null) ; }
protected ExprFunction1(Expr expr, String fName, String opSign)
{
super(fName, opSign) ;
this.expr = expr ;
}
public Expr getArg() { return expr ; }
@Override
public Expr getArg(int i)
{
if ( i == 1 )
return expr ;
return null ;
}
@Override
public int hashCode()
{
return getFunctionSymbol().hashCode() ^ Lib.hashCodeObject(expr) ;
}
@Override
public int numArgs() { return 1 ; }
// ---- Evaluation
@Override
final public NodeValue eval(Binding binding, FunctionEnv env)
{
NodeValue s = evalSpecial(binding, env) ;
if ( s != null )
return s ;
NodeValue x = eval(binding, env, expr) ;
return eval(x, env) ;
}
// Ideally, we would only have the FunctionEnv form but that break compatibility.
public NodeValue eval(NodeValue v, FunctionEnv env) { return eval(v) ; }
public abstract NodeValue eval(NodeValue v) ;
// Allow special cases.
protected NodeValue evalSpecial(Binding binding, FunctionEnv env) { return null ; }
@Override
final public Expr copySubstitute(Binding binding, boolean foldConstants)
{
Expr e = (expr == null ? null : expr.copySubstitute(binding, foldConstants)) ;
if ( foldConstants)
{
try {
if ( e != null && e.isConstant() )
return eval(e.getConstant(), new FunctionEnvBase()) ;
} catch (ExprEvalException ex) { /* Drop through */ }
}
return copy(e) ;
}
@Override
final public Expr applyNodeTransform(NodeTransform transform)
{
Expr e = (expr == null ? null : expr.applyNodeTransform(transform)) ;
return copy(e) ;
}
public abstract Expr copy(Expr expr) ;
@Override
public void visit(ExprVisitor visitor) { visitor.visit(this) ; }
public Expr apply(ExprTransform transform, Expr sub) { return transform.transform(this, sub) ; }
}