Option.java

/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 *
 * Licensed 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.google.cloud.pubsub;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.base.MoreObjects;

import java.io.Serializable;
import java.util.Objects;

/**
 * Base class for Pub/Sub operation options.
 */
abstract class Option implements Serializable {

  private static final long serialVersionUID = 4956295408130172192L;

  private final OptionType optionType;
  private final Object value;

  interface OptionType {

    String name();
  }

  Option(OptionType optionType, Object value) {
    this.optionType = checkNotNull(optionType);
    this.value = value;
  }

  @SuppressWarnings("unchecked")
  <T extends OptionType> T optionType() {
    return (T) optionType;
  }

  Object value() {
    return value;
  }

  @Override
  public boolean equals(Object obj) {
    if (!(obj instanceof Option)) {
      return false;
    }
    Option other = (Option) obj;
    return Objects.equals(optionType, other.optionType)
        && Objects.equals(value, other.value);
  }

  @Override
  public int hashCode() {
    return Objects.hash(optionType, value);
  }

  @Override
  public String toString() {
    return MoreObjects.toStringHelper(this)
        .add("name", optionType.name())
        .add("value", value)
        .toString();
  }
}