content: /*
   * 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 samples;
  
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStreamWriter;
  import java.io.Writer;
  
  import com.aliyun.oss.ClientException;
  import com.aliyun.oss.OSS;
  import com.aliyun.oss.OSSClientBuilder;
  import com.aliyun.oss.OSSException;
  import com.aliyun.oss.model.AppendObjectRequest;
  import com.aliyun.oss.model.AppendObjectResult;
  import com.aliyun.oss.model.OSSObject;
  
  /**
   * This sample demonstrates how to upload an object by append mode 
   * to Aliyun OSS using the OSS SDK for Java.
   */
  public class AppendObjectSample {
      
      private static String endpoint = "*** Provide OSS endpoint ***";
      private static String accessKeyId = "*** Provide your AccessKeyId ***";
      private static String accessKeySecret = "*** Provide your AccessKeySecret ***";
      
      private static String bucketName = "*** Provide bucket name ***";
      private static String key = "*** Provide key ***";
      
      public static void main(String[] args) throws IOException {        
          /*
           * Constructs a client instance with your account for accessing OSS
           */
          OSS client = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
          
          try {            
              /*
               * Append an object from specfied input stream, keep in mind that
               * position should be set to zero at first time.
               */
              String content = "Thank you for using Aliyun Object Storage Service";
              InputStream instream = new ByteArrayInputStream(content.getBytes());
              Long firstPosition = 0L;
              System.out.println("Begin to append object at position(" + firstPosition + ")");
              AppendObjectResult appendObjectResult = client.appendObject(
                      new AppendObjectRequest(bucketName, key, instream).withPosition(0L));
              System.out.println("\tNext position=" + appendObjectResult.getNextPosition() + 
                      ", CRC64=" + appendObjectResult.getObjectCRC() + "\n");
              
              /*
               * Continue to append the object from specfied file descriptor at last position
               */
              Long nextPosition = appendObjectResult.getNextPosition();
              System.out.println("Continue to append object at last position(" + nextPosition + "):");
              appendObjectResult = client.appendObject(
                      new AppendObjectRequest(bucketName, key, createTempFile())
                      .withPosition(nextPosition));
              System.out.println("\tNext position=" + appendObjectResult.getNextPosition() + 
                      ", CRC64=" + appendObjectResult.getObjectCRC());
              
              /*
               * View object type of the appendable object
               */
              OSSObject object = client.getObject(bucketName, key);
              System.out.println("\tObject type=" + object.getObjectMetadata().getObjectType() + "\n");
              // Do not forget to close object input stream if not use it any more
              object.getObjectContent().close();
              
              /*
               * Delete the appendable object
               */
              System.out.println("Deleting an appendable object");
              client.deleteObject(bucketName, key);
              
          } catch (OSSException oe) {
              System.out.println("Caught an OSSException, which means your request made it to OSS, "
                      + "but was rejected with an error response for some reason.");
              System.out.println("Error Message: " + oe.getErrorMessage());
              System.out.println("Error Code:       " + oe.getErrorCode());
              System.out.println("Request ID:      " + oe.getRequestId());
              System.out.println("Host ID:           " + oe.getHostId());
          } catch (ClientException ce) {
              System.out.println("Caught an ClientException, which means the client encountered "
                      + "a serious internal problem while trying to communicate with OSS, "
                      + "such as not being able to access the network.");
              System.out.println("Error Message: " + ce.getMessage());
          } finally {
              /*
               * Do not forget to shut down the client finally to release all allocated resources.
               */
              client.shutdown();
          }
      }
      
      private static File createTempFile() throws IOException {
          File file = File.createTempFile("oss-java-sdk-", ".txt");
          file.deleteOnExit();
  
          Writer writer = new OutputStreamWriter(new FileOutputStream(file));
          writer.write("abcdefghijklmnopqrstuvwxyz\n");
          writer.write("0123456789011234567890\n");
          writer.close();
  
          return file;
      }
  }
  