// 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.impala.common;

/**
 * "Indirection layer" that allows returning an object via an output
 * parameter of a function call, similar to a pointer or reference parameter
 * in C/C++.
 * Example:
 *   Reference<T> ref = new Reference<T>();
 *   createT(ref);  // calls ref.setRef()
 *   <do something with ref.getRef()>;
 */
public class Reference<RefType> {
  protected RefType ref_;

  public Reference(RefType ref) {
    this.ref_ = ref;
  }

  public Reference() {
    this.ref_ = null;
  }

  public RefType getRef() { return ref_; }
  public void setRef(RefType ref) { this.ref_ = ref; }
}