Ejercicio: Desarrollo y Despliegue de AWS Lambda con Java ​

package com.demo.model;

import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBHashKey;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable;

@DynamoDBTable(tableName = "Tasks")
public class Task {
    private String id;
    private String title;
    private String description;
    private String status;
    private String createdAt;

    @DynamoDBHashKey
    public String getId() { return id; }
    public void setId(String id) { this.id = id; }

    @DynamoDBAttribute
    public String getTitle() { return title; }
    public void setTitle(String title) { this.title = title; }

    @DynamoDBAttribute
    public String getDescription() { return description; }
    public void setDescription(String description) { this.description = description; }

    @DynamoDBAttribute
    public String getStatus() { return status; }
    public void setStatus(String status) { this.status = status; }

    @DynamoDBAttribute
    public String getCreatedAt() { return createdAt; }
    public void setCreatedAt(String createdAt) { this.createdAt = createdAt; }
}

package com.demo.util;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;

public class DynamoDBUtil {
    private static final AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().build();
    private static final DynamoDBMapper mapper = new DynamoDBMapper(client);

    public static DynamoDBMapper getMapper() {
        return mapper;
    }
}

package com.demo.handler;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent;
import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyResponseEvent;
import com.demo.model.Task;
import com.demo.util.DynamoDBUtil;
import com.google.gson.Gson;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

public class CreateTaskHandler implements RequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
    private static final Logger logger = LogManager.getLogger(CreateTaskHandler.class);
    private static final Gson gson = new Gson();

    @Override
    public APIGatewayProxyResponseEvent handleRequest(APIGatewayProxyRequestEvent input, Context context) {
        logger.info("Received request: " + input.getBody());

        try {
            Task task = gson.fromJson(input.getBody(), Task.class);
            task.setId(UUID.randomUUID().toString());
            task.setCreatedAt(java.time.Instant.now().toString());

            DynamoDBUtil.getMapper().save(task);

            Map<String, String> headers = new HashMap<>();
            headers.put("Content-Type", "application/json");
            headers.put("X-Custom-Header", "application/json");

            return new APIGatewayProxyResponseEvent()
                    .withStatusCode(201)
                    .withHeaders(headers)
                    .withBody(gson.toJson(task));
        } catch (Exception e) {
            logger.error("Error creating task: ", e);
            return new APIGatewayProxyResponseEvent()
                    .withStatusCode(500)
                    .withBody("{\"error\":\"Error creating task\"}");
        }
    }
}

package com.demo.handler;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent;
import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyResponseEvent;
import com.demo.model.Task;
import com.demo.util.DynamoDBUtil;
import com.google.gson.Gson;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.HashMap;
import java.util.Map;

public class GetTaskHandler implements RequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
    private static final Logger logger = LogManager.getLogger(GetTaskHandler.class);
    private static final Gson gson = new Gson();

    @Override
    public APIGatewayProxyResponseEvent handleRequest(APIGatewayProxyRequestEvent input, Context context) {
        String taskId = input.getPathParameters().get("id");
        logger.info("Getting task with ID: " + taskId);

        try {
            Task task = DynamoDBUtil.getMapper().load(Task.class, taskId);
            
            if (task == null) {
                return new APIGatewayProxyResponseEvent()
                        .withStatusCode(404)
                        .withBody("{\"error\":\"Task not found\"}");
            }

            Map<String, String> headers = new HashMap<>();
            headers.put("Content-Type", "application/json");

            return new APIGatewayProxyResponseEvent()
                    .withStatusCode(200)
                    .withHeaders(headers)
                    .withBody(gson.toJson(task));
        } catch (Exception e) {
            logger.error("Error getting task: ", e);
            return new APIGatewayProxyResponseEvent()
                    .withStatusCode(500)
                    .withBody("{\"error\":\"Error getting task\"}");
        }
    }
}