com.r573.enfili.common.resource.cloud.aws.dynamodb.DynamoDbManager.java Source code

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Here is the source code for com.r573.enfili.common.resource.cloud.aws.dynamodb.DynamoDbManager.java

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/*
 * Enfili
 * Project hosted at https://github.com/ryanhosp/enfili/
 * Copyright 2013 Ho Siaw Ping Ryan
 *    
 * Licensed 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 com.r573.enfili.common.resource.cloud.aws.dynamodb;

import java.util.ArrayList;
import java.util.Iterator;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.dynamodb.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBMapper;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBScanExpression;
import com.amazonaws.services.dynamodb.datamodeling.PaginatedScanList;
import com.r573.enfili.common.resource.cloud.aws.AwsConstants;
import com.r573.enfili.common.singleton.SingletonManager;

public class DynamoDbManager {
    private static SingletonManager<DynamoDbManager> singletonManager = new SingletonManager<DynamoDbManager>();;

    private AmazonDynamoDBClient client;
    private DynamoDBMapper mapper;

    public static void initFromEnv(String region, String tag) {
        initFromEnv(AwsConstants.DEFAULT_ENV_KEY_ACCESS_KEY, AwsConstants.DEFAULT_ENV_KEY_SECRET_KEY, region, tag);
    }

    public static void initFromEnv(String keyAccessKey, String keySecretKey, String region, String tag) {
        String awsAccessKey = System.getenv(keyAccessKey);
        String awsSecretKey = System.getenv(keySecretKey);
        if ((awsAccessKey == null) || (awsAccessKey.isEmpty())) {
            throw new IllegalStateException("AWS_ACCESS_KEY environment variable not defined");
        }
        if ((awsSecretKey == null) || (awsSecretKey.isEmpty())) {
            throw new IllegalStateException("AWS_SECRET_KEY environment variable not defined");
        }

        initWithCredentials(awsAccessKey, awsSecretKey, region, tag);
    }

    public static void initWithCredentials(String awsAccessKey, String awsSecretKey, String region, String tag) {
        AWSCredentials awsCredentials = new BasicAWSCredentials(awsAccessKey, awsSecretKey);
        initWithCredentials(awsCredentials, region, tag);
    }

    public static void initWithCredentials(AWSCredentials awsCredentials, String region, String tag) {
        DynamoDbManager manager = new DynamoDbManager(awsCredentials, region);

        singletonManager.addInstance(tag, manager);
    }

    public static DynamoDbManager getDefaultInstance() {
        return singletonManager.getDefaultInstance();
    }

    public static DynamoDbManager getInstance(String tag) {
        return singletonManager.getInstance(tag);
    }

    public static void removeInstance(String tag) {
        singletonManager.removeInstance(tag);
    }

    private DynamoDbManager(AWSCredentials awsCredentials, String region) {
        client = new AmazonDynamoDBClient(awsCredentials);
        client.setEndpoint("https://dynamodb." + region + ".amazonaws.com");
        mapper = new DynamoDBMapper(client);
    }

    public <T> T getItem(Class<T> clazz, Object hashKey) {
        return mapper.load(clazz, hashKey);
    }

    public <T> ArrayList<T> getItemsByScan(Class<T> clazz) {
        DynamoDBScanExpression scanExpression = new DynamoDBScanExpression().withLimit(40);
        PaginatedScanList<T> scanList = mapper.scan(clazz, scanExpression);

        ArrayList<T> results = new ArrayList<T>();
        Iterator<T> it = scanList.iterator();
        while (it.hasNext()) {
            T element = it.next();
            results.add(element);
        }
        return results;
    }

    public void saveItem(Object item) {
        mapper.save(item);
    }
}