hadoop S3ListResult 源码

haddop S3ListResult 代码

文件路径：/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3ListResult.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.hadoop.fs.s3a;

import java.util.Collection;
import java.util.List;
import java.util.stream.Collectors;

import com.amazonaws.services.s3.model.ListObjectsV2Result;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import org.slf4j.Logger;

/**
 * API version-independent container for S3 List responses.
 */
public class S3ListResult {
  private ObjectListing v1Result;
  private ListObjectsV2Result v2Result;

  protected S3ListResult(ObjectListing v1, ListObjectsV2Result v2) {
    v1Result = v1;
    v2Result = v2;
  }

  /**
   * Restricted constructors to ensure v1 or v2, not both.
   * @param result v1 result
   * @return new list result container
   */
  public static S3ListResult v1(ObjectListing result) {
    return new S3ListResult(result, null);
  }

  /**
   * Restricted constructors to ensure v1 or v2, not both.
   * @param result v2 result
   * @return new list result container
   */
  public static S3ListResult v2(ListObjectsV2Result result) {
    return new S3ListResult(null, result);
  }

  /**
   * Is this a v1 API result or v2?
   * @return true if v1, false if v2
   */
  public boolean isV1() {
    return v1Result != null;
  }

  public ObjectListing getV1() {
    return v1Result;
  }

  public ListObjectsV2Result getV2() {
    return v2Result;
  }

  public List<S3ObjectSummary> getObjectSummaries() {
    if (isV1()) {
      return v1Result.getObjectSummaries();
    } else {
      return v2Result.getObjectSummaries();
    }
  }

  public boolean isTruncated() {
    if (isV1()) {
      return v1Result.isTruncated();
    } else {
      return v2Result.isTruncated();
    }
  }

  public List<String> getCommonPrefixes() {
    if (isV1()) {
      return v1Result.getCommonPrefixes();
    } else {
      return v2Result.getCommonPrefixes();
    }
  }

  /**
   * Get the list of keys in the object summary.
   * @return a possibly empty list
   */
  private List<String> objectSummaryKeys() {
    return getObjectSummaries().stream()
        .map(S3ObjectSummary::getKey)
        .collect(Collectors.toList());
  }

  /**
   * Does this listing have prefixes or objects?
   * @return true if the result is non-empty
   */
  public boolean hasPrefixesOrObjects() {

    return !(getCommonPrefixes()).isEmpty()
        || !getObjectSummaries().isEmpty();
  }

  /**
   * Does this listing represent an empty directory?
   * @param dirKey directory key
   * @return true if the list is considered empty.
   */
  public boolean representsEmptyDirectory(
      final String dirKey) {
    // If looking for an empty directory, the marker must exist but
    // no children.
    // So the listing must contain the marker entry only as an object,
    // and prefixes is null
    List<String> keys = objectSummaryKeys();
    return keys.size() == 1 && keys.contains(dirKey)
        && getCommonPrefixes().isEmpty();
  }

  /**
   * Dump the result at debug level.
   * @param log log to use
   */
  public void logAtDebug(Logger log) {
    Collection<String> prefixes = getCommonPrefixes();
    Collection<S3ObjectSummary> summaries = getObjectSummaries();
    log.debug("Prefix count = {}; object count={}",
        prefixes.size(), summaries.size());
    for (S3ObjectSummary summary : summaries) {
      log.debug("Summary: {} {}", summary.getKey(), summary.getSize());
    }
    for (String prefix : prefixes) {
      log.debug("Prefix: {}", prefix);
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop AWSBadRequestException 源码

hadoop AWSClientIOException 源码

hadoop AWSCredentialProviderList 源码

hadoop AWSNoResponseException 源码

hadoop AWSRedirectException 源码

hadoop AWSS3IOException 源码

hadoop AWSServiceIOException 源码

hadoop AWSServiceThrottledException 源码

hadoop AWSStatus500Exception 源码

hadoop AnonymousAWSCredentialsProvider 源码