com.google.cloud.hadoop.gcsio.ObjectWriteConditions Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of gcsio Show documentation

An implementation of org.apache.hadoop.fs.FileSystem targeting Google Cloud Storage

There is a newer version: 3.0.5

/*
 * Copyright 2014 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.hadoop.gcsio;

import com.google.api.services.storage.Storage.Objects.Insert;
import com.google.common.base.Optional;

/**
 * Conditions on which a object write should be allowed to continue. Corresponds to setting
 * IfGenerationMatch and IfMetaGenerationMatch in API requests.
 */
public class ObjectWriteConditions {

  /**
   * No conditions for completing the write.
   */
  public static final ObjectWriteConditions NONE = new ObjectWriteConditions();

  private final Optional contentGenerationMatch;
  private final Optional metaGenerationMatch;

  public ObjectWriteConditions() {
    metaGenerationMatch = Optional.absent();
    contentGenerationMatch = Optional.absent();
  }

  public ObjectWriteConditions(Optional contentGenerationMatch,
      Optional metaGenerationMatch) {
    this.contentGenerationMatch = contentGenerationMatch;
    this.metaGenerationMatch = metaGenerationMatch;
  }

  public boolean hasContentGenerationMatch() {
    return contentGenerationMatch.isPresent();
  }

  public boolean hasMetaGenerationMatch() {
    return metaGenerationMatch.isPresent();
  }

  public long getContentGenerationMatch() {
    return contentGenerationMatch.get();
  }

  public long getMetaGenerationMatch() {
    return metaGenerationMatch.get();
  }

  /**
   * Apply the conditions represented by this object to an Insert operation.
   */
  public void apply(Insert objectToInsert) {
    if (hasContentGenerationMatch()) {
      objectToInsert.setIfGenerationMatch(getContentGenerationMatch());
    }

    if (hasMetaGenerationMatch()) {
      objectToInsert.setIfMetagenerationMatch(getMetaGenerationMatch());
    }
  }
}