org.apache.openjpa.kernel.exps.Extension Maven / Gradle / Ivy
/*
* 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.openjpa.kernel.exps;
import org.apache.openjpa.kernel.StoreContext;
/**
* A value produced from evaluating a custom extension.
*
* @author Abe White
*/
class Extension
extends Val {
private final FilterListener _listener;
private final Val _target;
private final Val _arg;
/**
* Constructor. Supply filter listener, its target value, and
* its argument value, if any.
*/
public Extension(FilterListener listener, Val target, Val arg) {
_listener = listener;
_target = target;
_arg = arg;
}
public Class getType() {
Class targetClass = (_target == null) ? null : _target.getType();
return _listener.getType(targetClass, getArgTypes());
}
public void setImplicitType(Class type) {
}
protected Object eval(Object candidate, Object orig,
StoreContext ctx, Object[] params) {
Object target = null;
Class targetClass = null;
if (_target != null) {
target = _target.eval(candidate, orig, ctx, params);
targetClass = _target.getType();
}
Object arg = null;
if (_arg != null)
arg = _arg.eval(candidate, orig, ctx, params);
return _listener.evaluate(target, targetClass, getArgs(arg),
getArgTypes(), candidate, ctx);
}
private Class[] getArgTypes() {
if (_arg == null)
return null;
if (_arg instanceof Args)
return ((Args) _arg).getTypes();
return new Class[]{ _arg.getType() };
}
private Object[] getArgs(Object arg) {
if (arg == null)
return null;
if (_arg instanceof Args)
return (Object[]) arg;
return new Object[]{ arg };
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
if (_target != null)
_target.acceptVisit(visitor);
if (_arg != null)
_arg.acceptVisit(visitor);
visitor.exit(this);
}
}