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/*
 * Copyright (c) 2010-2015 Pivotal Software, 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. See accompanying
 * LICENSE file.
 */
package com.gemstone.gemfire.cache;

import com.gemstone.gemfire.internal.i18n.LocalizedStrings;

import java.io.*;
import java.util.*;

/**
 * Specifies how access to the region is affected when one or more required
 * roles are lost. A role is lost when it is are offline and no longer
 * present in the system membership.
 * The LossAction is specified when configuring a region's
 * {@link com.gemstone.gemfire.cache.MembershipAttributes}.
 * 
 * @author Kirk Lund
 * @since 5.0
 */
public class LossAction implements Serializable {
  private static final long serialVersionUID = -832035480397447797L;

  // NOTE: to change/add these files are impacted:
  //   LossAction, package.html
  
  /**
   * The region is unavailable when required roles are missing. All operations
   * including read and write access are denied.  All read and write operations
   * on the region will result in {@link RegionAccessException} while any 
   * required roles are absent.  Basic administration of the region is allowed,
   * including {@linkplain Region#close close} and 
   * {@linkplain Region#localDestroyRegion() localDestroyRegion}.
   */
  public static final LossAction NO_ACCESS = 
      new LossAction("NO_ACCESS");

  /** 
   * Only local access to the region is allowed when required roles are 
   * missing.  All distributed write operations on the region will throw 
   * {@link RegionAccessException} while any required roles are absent.
   * Reads which result in a netSearch behave normally, while any attempt
   * to invoke a netLoad is not allowed.
   */
  public static final LossAction LIMITED_ACCESS = 
      new LossAction("LIMITED_ACCESS");

  /** 
   * Access to the region is unaffected when required roles are missing. 
   */
  public static final LossAction FULL_ACCESS = 
      new LossAction("FULL_ACCESS");

  /** 
   * Loss of required roles causes the entire cache to be closed. In addition,
   * this process will disconnect from the DistributedSystem and then
   * reconnect. Attempting to use any existing references to the regions
   * or cache will throw a {@link CacheClosedException}.
   */
  public static final LossAction RECONNECT = 
      new LossAction("RECONNECT");

  /** The name of this mirror type. */
  private final transient String name;

  // The 4 declarations below are necessary for serialization
  /** byte used as ordinal to represent this Scope */
  public final byte ordinal = nextOrdinal++;

  private static byte nextOrdinal = 0;
  
  private static final LossAction[] PRIVATE_VALUES =
    { NO_ACCESS, LIMITED_ACCESS, FULL_ACCESS, RECONNECT };
  
  /** List of all LossAction values */
  public static final List VALUES = 
    Collections.unmodifiableList(Arrays.asList(PRIVATE_VALUES));

  private Object readResolve() throws ObjectStreamException {
    return PRIVATE_VALUES[ordinal];  // Canonicalize
  }
  
  /** Creates a new instance of LossAction. */
  private LossAction(String name) {
      this.name = name;
  }
  
  /** Return the LossAction represented by specified ordinal */
  public static LossAction fromOrdinal(byte ordinal) {
    return PRIVATE_VALUES[ordinal];
  }
  
  /** Return the LossAction specified by name */
  public static LossAction fromName(String name) {
    if (name == null || name.length() == 0) {
      throw new IllegalArgumentException(LocalizedStrings.LossAction_INVALID_LOSSACTION_NAME_0.toLocalizedString(name));
    }
    for (int i = 0; i < PRIVATE_VALUES.length; i++) {
      if (name.equals(PRIVATE_VALUES[i].name)) {
        return PRIVATE_VALUES[i];
      }
    }
    throw new IllegalArgumentException(LocalizedStrings.LossAction_INVALID_LOSSACTION_NAME_0.toLocalizedString(name));
  }
  
  /** Returns true if this is NO_ACCESS. */
  public boolean isNoAccess() {
    return this == NO_ACCESS;
  }
  
  /** Returns true if this is LIMITED_ACCESS. */
  public boolean isLimitedAccess() {
    return this == LIMITED_ACCESS;
  }
  
  /** Returns true if this is FULL_ACCESS. */
  public boolean isAllAccess() {
    return this == FULL_ACCESS;
  }
  
  /** Returns true if this is RECONNECT. */
  public boolean isReconnect() {
    return this == RECONNECT;
  }
  
  /** 
   * Returns a string representation for this loss action.
   * @return the name of this loss action
   */
  @Override
  public String toString() {
      return this.name;
  }
  
}