GettingStartedTryQuery.java

/*
* Copyright 2014-2015 Amazon.com, Inc. or its affiliates. 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://aws.amazon.com/apache2.0
*
* 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.amazonaws.codesamples;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;

import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.ItemCollection;
import com.amazonaws.services.dynamodbv2.document.QueryOutcome;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.document.spec.QuerySpec;
import com.amazonaws.services.dynamodbv2.document.utils.ValueMap;

public class GettingStartedTryQuery {

    static DynamoDB dynamoDB = new DynamoDB(new AmazonDynamoDBClient(
            new ProfileCredentialsProvider()));
    static SimpleDateFormat dateFormatter = new SimpleDateFormat(
        "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

    public static void main(String[] args) throws Exception {

        try {

            String forumName = "Amazon DynamoDB";
            String threadSubject = "DynamoDB Thread 1";

            // Get an item.
            getBook(101, "ProductCatalog");

            // Query replies posted in the past 15 days for a forum thread.
            findRepliesInLast15DaysWithConfig("Reply", forumName, threadSubject);
        } catch (Exception e) {
            System.err.println(e.getMessage());
        }
    }

    private static void getBook(int id, String tableName) {

        Table table = dynamoDB.getTable(tableName);

        Item item = table.getItem("Id", // attribute name
                id, // attribute value
                "Id, ISBN, Title, Authors", // projection expression
                null); // name map - don't need this

        System.out.println("GetItem: printing results...");
        System.out.println(item.toJSONPretty());

    }

    private static void findRepliesInLast15DaysWithConfig(
        String tableName, String forumName, String threadSubject) {

        String replyId = forumName + "#" + threadSubject;
        long twoWeeksAgoMilli = (new Date()).getTime()
            - (15L * 24L * 60L * 60L * 1000L);
        Date twoWeeksAgo = new Date();
        twoWeeksAgo.setTime(twoWeeksAgoMilli);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String twoWeeksAgoStr = df.format(twoWeeksAgo);

        Table table = dynamoDB.getTable(tableName);

        QuerySpec querySpec = new QuerySpec()
            .withKeyConditionExpression("Id = :v1 and ReplyDateTime > :v2")
            .withValueMap(new ValueMap()
                .withString(":v1", replyId)
                .withString(":v2", twoWeeksAgoStr))
            .withProjectionExpression("Message, ReplyDateTime, PostedBy");

        ItemCollection<QueryOutcome> items = table.query(querySpec);
        Iterator<Item> iterator = items.iterator();

        System.out.println("Query: printing results...");

        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
    }

}