com.emc.vipr.s3.sample._10_AtomicAppend.java Source code

Introduction

Here is the source code for com.emc.vipr.s3.sample._10_AtomicAppend.java

Source

/*
 * Copyright 2013 EMC Corporation. 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.
 * A copy of the License is located at
 *
 * http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 * or in the "license" file accompanying this file. This file 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.emc.vipr.s3.sample;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.util.StringInputStream;
import com.emc.vipr.services.s3.ViPRS3Client;
import com.emc.vipr.services.s3.model.AppendObjectResult;

public class _10_AtomicAppend {

    public static void main(String[] args) throws Exception {
        // create the ViPR S3 Client
        ViPRS3Client s3 = ViPRS3Factory.getS3Client();

        // object key to create, update, and append
        String key = "atomic-append.txt";
        String bucketName = ViPRS3Factory.S3_BUCKET; // bucket to create object in
        String content = "Hello World!"; // initial object content
        StringInputStream stream;

        // first create an initial object
        stream = new StringInputStream(content);
        System.out.println(String.format("creating initial object %s/%s", bucketName, key));
        s3.putObject(bucketName, key, stream, null);

        // read object and print content
        System.out.println(String.format("initial object %s/%s with content: [%s]", bucketName, key,
                readObject(s3, bucketName, key)));

        // append to the end of the object
        String content2 = " ... and Universe!!";
        AppendObjectResult result = s3.appendObject(bucketName, key, new StringInputStream(content2), null);

        // the offset at which our appended data was written is returned
        // (this is the previous size of the object)
        long appendOffset = result.getAppendOffset();

        // read object and print content
        System.out.println(String.format("final object %s/%s with content: [%s]", bucketName, key,
                readObject(s3, bucketName, key)));
    }

    private static String readObject(ViPRS3Client s3, String bucketName, String key) throws IOException {
        // read the object from the demo bucket
        S3Object object = s3.getObject(bucketName, key);

        // convert object to a text string
        BufferedReader reader = new BufferedReader(new InputStreamReader(object.getObjectContent()));
        String content = reader.readLine();
        return content;
    }
}