geode-core/src/main/java/org/apache/geode/cache/InterestResultPolicy.java

/*
 * 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.geode.cache;

import java.io.ObjectStreamException;
import java.io.Serializable;

import org.apache.geode.annotations.Immutable;
import org.apache.geode.internal.cache.tier.sockets.InterestResultPolicyImpl;

/**
 * Class <code>InterestResultPolicy</code> is an enumerated type for a register interest result. The
 * result of a call to Region.registerInterest can be the keys and current values, just the keys or
 * nothing.
 *
 *
 * @see org.apache.geode.cache.Region#registerInterest(Object)
 * @see org.apache.geode.cache.Region#registerInterestRegex(String)
 *
 * @since GemFire 4.2.3
 */
public class InterestResultPolicy implements Serializable {
  private static final long serialVersionUID = -4993765891973030160L;

  @Immutable
  private static final InterestResultPolicy[] VALUES = new InterestResultPolicy[3];

  @Immutable
  public static final InterestResultPolicy NONE = new InterestResultPolicyImpl("NONE", 0);
  @Immutable
  public static final InterestResultPolicy KEYS = new InterestResultPolicyImpl("KEYS", 1);
  @Immutable
  public static final InterestResultPolicy KEYS_VALUES =
      new InterestResultPolicyImpl("KEYS_VALUES", 2);

  /**
   * The <code>InterestResultPolicy</code> used by default; it is {@link #KEYS_VALUES}.
   */
  @Immutable
  public static final InterestResultPolicy DEFAULT = KEYS_VALUES;


  /** The name of this <code>InterestResultPolicy</code>. */
  private final transient String name;

  /** The ordinal representing this <code>InterestResultPolicy</code>. */
  public final byte ordinal;

  protected Object readResolve() throws ObjectStreamException {
    return VALUES[ordinal]; // Canonicalize
  }


  /** should only be called from InterestResultPolicyImpl */
  protected InterestResultPolicy(String name, int ordinal) {
    this.name = name;
    this.ordinal = (byte) ordinal;
    VALUES[this.ordinal] = this;
  }

  /** Returns the <code>InterestResultPolicy</code> represented by specified ordinal */
  public static InterestResultPolicy fromOrdinal(byte ordinal) {
    return VALUES[ordinal];
  }

  /**
   * Returns the ordinal value.
   *
   * @since GemFire 5.0
   */
  public byte getOrdinal() {
    return this.ordinal;
  }

  /**
   * Returns true if this <code>InterestResultPolicy</code> is {@link #NONE}.
   *
   * @return true if this <code>InterestResultPolicy</code> is {@link #NONE}.
   */
  public boolean isNone() {
    return this == NONE;
  }

  /**
   * Returns true if this <code>InterestResultPolicy</code> is {@link #KEYS}.
   *
   * @return true if this <code>InterestResultPolicy</code> is {@link #KEYS}.
   */
  public boolean isKeys() {
    return this == KEYS;
  }

  /**
   * Returns true if this <code>InterestResultPolicy</code> is {@link #KEYS_VALUES}.
   *
   * @return true if this <code>InterestResultPolicy</code> is {@link #KEYS_VALUES}.
   */
  public boolean isKeysValues() {
    return this == KEYS_VALUES;
  }

  /**
   * Returns true if this <code>InterestResultPolicy</code> is the default.
   *
   * @return true if this <code>InterestResultPolicy</code> is the default.
   */
  public boolean isDefault() {
    return this == DEFAULT;
  }

  /**
   * Returns a string representation for this <code>InterestResultPolicy</code>.
   *
   * @return the name of this data policy.
   */
  @Override // GemStoneAddition
  public String toString() {
    return this.name;
  }
}