DocumentAPIQuery.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.document;

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.Page;
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 DocumentAPIQuery {

    static DynamoDB dynamoDB = new DynamoDB(new AmazonDynamoDBClient(new ProfileCredentialsProvider()));

    static String tableName = "Reply";

    public static void main(String[] args) throws Exception {
        
        String forumName = "Amazon DynamoDB";
        String threadSubject = "DynamoDB Thread 1";

        findRepliesForAThread(forumName, threadSubject);
        findRepliesForAThreadSpecifyOptionalLimit(forumName, threadSubject);
        findRepliesInLast15DaysWithConfig(forumName, threadSubject);
        findRepliesPostedWithinTimePeriod(forumName, threadSubject);
        findRepliesUsingAFilterExpression(forumName, threadSubject);
    }
    
    private static void findRepliesForAThread(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;
        
        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId));
        
        ItemCollection<QueryOutcome> items = table.query(spec);
        
        System.out.println("\nfindRepliesForAThread results:");

        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
        
    }

    private static void findRepliesForAThreadSpecifyOptionalLimit(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);
        
        String replyId = forumName + "#" + threadSubject;   
               
        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId))
            .withMaxPageSize(1);

        ItemCollection<QueryOutcome> items = table.query(spec);
        
        System.out.println("\nfindRepliesForAThreadSpecifyOptionalLimit results:");

        // Process each page of results
        int pageNum = 0;
        for (Page<Item, QueryOutcome> page : items.pages()) {
            
            System.out.println("\nPage: " + ++pageNum);

            // Process each item on the current page
            Iterator<Item> item = page.iterator();
            while (item.hasNext()) {
                System.out.println(item.next().toJSONPretty());
            }
        }
    }
    
    private static void findRepliesInLast15DaysWithConfig(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        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);
        
        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime <= :v_reply_dt_tm")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_reply_dt_tm", twoWeeksAgoStr));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesInLast15DaysWithConfig results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }
    
    private static void findRepliesPostedWithinTimePeriod(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long startDateMilli = (new Date()).getTime() - (15L*24L*60L*60L*1000L); 
        long endDateMilli = (new Date()).getTime() - (5L*24L*60L*60L*1000L);    
        java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String startDate = df.format(startDateMilli);
        String endDate = df.format(endDateMilli);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime between :v_start_dt and :v_end_dt")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_start_dt", startDate)
                .withString(":v_end_dt", endDate));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesPostedWithinTimePeriod results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
    }

    private static void findRepliesUsingAFilterExpression(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);
        
        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id")
            .withFilterExpression("PostedBy = :v_postedby")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_postedby", "User B"));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesUsingAFilterExpression results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
     }
    
}