updated `README.md`

README.md

@@ -1,423 +1,66 @@
-
-
-# Part 1 - Domain Implementation<br>
-* _Domain objects_ are the backbone for an application and contain the [business logic](https://en.wikipedia.org/wiki/Business_logic).
-* Create a sub package of `io.zipcoder.tc_spring_poll_application` named `domain`.
-
-
--
-# Part 1.1 - Create class `Option`
-* Create an `Option` class in the `domain` sub-package.
-* `Option` class signature is annotated with `@Entity`
-* `Option` has an `id` instance variable of type `Long`
-	* `id` should be `annotated` with
-		* `@Id`
-			* denotes primary key of this entity
-		* `@GeneratedValue`
-			* configures the way of increment of the specified `column(field)`
-		* `@Column(name = "OPTION_ID")`
-			* specifies mapped column for a persistent property or field
-
-* `Option` has a `value` instance variable of type `String`
-	* `value` should be `annotated` with
-		* `@Column(name = "OPTION_VALUE")`
-
-* Create a `getter` and `setter` for each of the respective instance variables.
-
-
--
-# Part 1.2 - Create class `Poll`
-* Create a `Poll` class in the `domain` sub-package.
-* `Poll` class signature is annotated with `@Entity`
-* `Poll` has an `id` instance variable of type `Long`
-	* `id` should be `annotated` with
-		* `@Id`
-		* `@GeneratedValue`
-		* `Column(name = "POLL_ID")`
-
-* `Poll` has a `question` instance variable of type `String`
-	* `question` should be `annotated` with
-		* `@Column(name = "QUESTION")`
-
-* `Poll` has an `options` instance variable of type `Set` of `Option`
-	* `options` should be `annotated` with
-		* `@OneToMany(cascade = CascadeType.ALL)`
-		* `@JoinColumn(name = "POLL_ID")`
-		* `@OrderBy`
-
-* Create a `getter` and `setter` for each of the respective instance variables.
-
-
-
--
-# Part 1.3 - Create class `Vote`
-* Create a `Vote` class in the `domain` sub-package.
-* `Vote` class signature is annotated with `@Entity`
-* `Vote` has an `id` instance variable of type `Long`
-	* `id` should be `annotated` with
-		* `@Id`
-		* `@GeneratedValue`
-		* `Column(name = "VOTE_ID")`
-
-* `Vote` has a `option` instance variable of type `Option`
-	* `option` should be `annotated` with
-		* `@ManyToOne`
-		* `@JoinColumn(name = "OPTION_ID")`
-
-* Create a `getter` and `setter` for each of the respective instance variables.
-
-
-
-
--
--
-# Part 2 - Repository Implementation
-* _Repositories_ or [Data Access Objects (DAO)](https://en.wikipedia.org/wiki/Data_access_object), provide an abstraction for interacting with _datastores_.
-* Typically DAOs include an interface that provides a set of finder methods such as `findById`, `findAll`, for retrieving data, and methods to persist and delete data.
-* It is customary to have one `Repository` per `domain` object.
-* Create a sub-package of `io.zipcoder.tc_spring_poll_application` named `repositories`.
-
-
--
-# Part 2.1 - Create interface `OptionRepository`
-* Create an `OptionRepository` interface in the `repositories` subpackage.
-* `OptionRepository` extends `CrudRepository<Option, Long>`
-
--
-# Part 2.2 - Create interface `PollRepository`
-* Create a `PollRepository` interface in the `repositories` subpackage.
-* `PollRepository` extends `CrudRepository<Poll, Long>`
-
--
-# Part 2.3 - Create interface `VoteRepository`
-* Create a `VoteRepository` interface in the `repositories` subpackage.
-* `VoteRepository` extends `CrudRepository<Vote, Long>`
-
-
-
-
-
-
 -
--
-# Part 3 - Controller Implementation
-* _Controllers_ provides all of the necessary [endpoints](https://en.wikipedia.org/wiki/Web_API#Endpoints) to access and manipulate respective domain objects.
-	*  REST resources are identified using URI endpoints.
-* Create a sub package of `io.zipcoder.tc_spring_poll_application` named `controller`.
-
-
--
-# Part 3.1 - Create class `PollController`
-* Create a `PollController` class in the `controller` sub package.
-	* `PollController` signature should be `annotated` with `@RestController`
-
-* `PollController` has a `pollRepository` instance variable of type `PollRepository`
-	* `pollRepository` should be `annotated` with `@Inject`
-
--
-# Part 3.1.1 - Create `GET` request method
-* The method definition below supplies a `GET` request on the `/polls` endpoint which provides a collection of all of the polls available in the QuickPolls application. Copy and paste this into your `PollController` class.
-
-```java
-@RequestMapping(value="/polls", method= RequestMethod.GET)
-public ResponseEntity<Iterable<Poll>> getAllPolls() {
-    Iterable<Poll> allPolls = pollRepository.findAll();
-    return new ResponseEntity<>(allPolls, HttpStatus.OK);
-}
-```
-
-* The method above begins with reading all of the polls using the `PollRepository`.
-* We then create an instance of `ResponseEntity` and pass in `Poll` data and the `HttpStatus.OK` status value.
-* The `Poll` data becomes part of the response body and `OK` (code 200) becomes the response status code.
-
-
-
-
--
-# Part 3.1.2 - Testing via Postman
-* Ensure that the `start-class` tag in your `pom.xml` encapsulates `io.zipcoder.springdemo.QuickPollApplication`
-* Open a command line and navigate to the project's root directory and run this command:
-	* `mvn spring-boot:run`
-* Launch the [Postman](https://chrome.google.com/webstore/detail/postman/fhbjgbiflinjbdggehcddcbncdddomop?hl=en) app in your Chrome browser and enter the URL `http://localhost:8080/polls` and hit Send.
-* Because we don’t have any polls created yet, this command should result in an empty collection.
-
-
-
-
--
-# Part 3.1.3 - Create `POST` request method
-* We accomplish the capability to add new polls to the `PollController` by implementing the `POST` verb functionality in a `createPoll` method:
-
-```java
-@RequestMapping(value="/polls", method=RequestMethod.POST)
-public ResponseEntity<?> createPoll(@RequestBody Poll poll) {
-        poll = pollRepository.save(poll);
-        return new ResponseEntity<>(null, HttpStatus.CREATED);
-}
-```
-
-* Take note that the method
-	* has a parameter of type `@RequestBody Poll poll`
-		* `@RequestBody` tells Spring that the entire request body needs to be converted to an instance of Poll
-	* delegates the `Poll` persistence to `PollRepository`’s save method
-		* `poll = pollRepository.save(poll);`
-
-
-
-
--
-# Part 3.1.4 - Modify `createPoll`
-* Best practice is to convey the URI to the newly created resource using the Location HTTP header via Spring's `ServletUriComponentsBuilder` utility class. This will ensure that the client has some way of knowing the URI of the newly created Poll.
-
-```java
-URI newPollUri = ServletUriComponentsBuilder
-	.fromCurrentRequest()
-	.path("/{id}")
-	.buildAndExpand(poll.getId())
-	.toUri();
-```
-
-* Modify the `createPoll` method so that it returns a `ResponseEntity` which takes an argument of a `new HttpHeaders()` whose _location_ has been _set_ to the above `newPollUri` via the `setLocation` method.
-
-
-
-
--
-# Part 3.1.5 - Create `GET` request method
-* The code snippet below enables us to access an individual poll.
-* The _value attribute_ in the `@RequestMapping` takes a URI template `/polls/{pollId}`.
-* The placeholder `{pollId}` along with `@PathVarible` annotation allows Spring to examine the request URI path and extract the `pollId` parameter value.
-* Inside the method, we use the `PollRepository`’s `findOne` finder method to read the poll and pass it as part of a `ResponseEntity`.
-
-```java
-@RequestMapping(value="/polls/{pollId}", method=RequestMethod.GET)
-public ResponseEntity<?> getPoll(@PathVariable Long pollId) {
-	Poll p = pollRepository.findOne(pollId);
-	return new ResponseEntity<> (p, HttpStatus.OK);
-}
-```
-
-
-
+# Pagination
+* To optimize performance, it is important to limit the amount of data returned, especially in the case of a mobile client.
+* REST services have the ability to give clients access large datasets in manageable chunks, by splitting the data into discrete pages or _paging data_. 
+* For this lab, we will approach this by implementing the _page number pagination pattern_.
 
 -
-# Part 3.1.6 - Create `UPDATE` request method
-* The code snippet below enables us to update a poll.
-
-```java
-RequestMapping(value="/polls/{pollId}", method=RequestMethod.PUT)
-public ResponseEntity<?> updatePoll(@RequestBody Poll poll, @PathVariable Long pollId) {
-        // Save the entity
-        Poll p = pollRepository.save(poll);
-        return new ResponseEntity<>(HttpStatus.OK);
-}
-```
-
+### Get Data From Page 
 
+* For example, a client wanting a blog post in page 3 of a hypothetical blog service can use a `GET` method resembling the following:
+`http://blog.example.com/posts?page=3`
 
 -
-# Part 3.1.7 - Create `DELETE` request method.
-
-* The code snippet below enables us to delete a poll.
-
-```java
-@RequestMapping(value="/polls/{pollId}", method=RequestMethod.DELETE)
-public ResponseEntity<?> deletePoll(@PathVariable Long pollId) {
-        pollRepository.delete(pollId);
-        return new ResponseEntity<>(HttpStatus.OK);
-}
-```
-
-
-
+### Limit Data Retrieved From Page
+* It is possible for the client to override the default page size by passing in a page-size parameter:
+`http://blog.example.com/posts?page=3&size=20`
 
 -
-# Part 3.1.8 - Test
-* Restart the QuickPoll application.
-* Use Postman to execute a `PUT` to `http://localhost:8080/polls/1` whose request body is the `JSON` object below.
-* You can modify the request body in Postman by navigating to the `Body` tab, selecting the `raw` radio button, and selecting the `JSON` option from the text format dropdown.
-
-```JSON
-{
-    "id": 1,
-        "question": "What's the best netflix original?",
-        "options": [
-	    { "id": 1, "value": "Black Mirror" },
-	    { "id": 2, "value": "Stranger Things" },
-	    { "id": 3, "value": "Orange is the New Black"},
-	    { "id": 4, "value": "The Get Down" }
-	]
-}
-```
-
+### Pagination Specific Information
+* Pagination-specific information includes
+	* total number of records
+	* total number of pages
+	* current page number
+	* page size
 
 -
-# Part 3.2 - Create class `VoteController`
-* Following the principles used to create `PollController`, we implement the `VoteController` class.
-* Below is the code for the `VoteController` class along with the functionality to create a vote.
-* The `VoteController` uses an injected instance of `VoteRepository` to perform `CRUD` operations on Vote instances.
-
-```java
-@RestController
-public class VoteController {
-    @Inject
-    private VoteRepository voteRepository;
-
-    @RequestMapping(value = "/polls/{pollId}/votes", method = RequestMethod.POST)
-    public ResponseEntity<?> createVote(@PathVariable Long pollId, @RequestBody Vote
-            vote) {
-        vote = voteRepository.save(vote);
-        // Set the headers for the newly created resource
-        HttpHeaders responseHeaders = new HttpHeaders();
-        responseHeaders.setLocation(ServletUriComponentsBuilder.
-                fromCurrentRequest().path("/{id}").buildAndExpand(vote.getId()).toUri());
-        return new ResponseEntity<>(null, responseHeaders, HttpStatus.CREATED);
-    }
-}
-```
-
-# Part 3.2.1 - Testing `VoteController`
-* To test the voting capabilities, `POST` a new Vote to the `/polls/1/votes` endpoint with the option object expressed in `JSON` below.
-* On successful request execution, you will see a Location response header with value http://localhost:8080/polls/1/votes/1.
+### Pagination Data
+* In the above scenario, one would expect a response body with pagination infromation closely resembling the `JSON` object below.
 
 ```JSON
 {
-    "option": { "id": 1, "value": "Black Mirror" }
-}
-```
-
-
-
-
--
-# Part 3.2.2 - Modify `VoteRepository`
-* The method `findAll` in the `VoteRepository` retrieves all votes in a Database rather than a given poll.
-* To ensure we can get votes for a given poll, we must add the code below to our `VoteRepository`.
-
-```java
-public interface VoteRepository extends CrudRepository<Vote, Long> {
-    @Query(value = "SELECT v.* " +
-            "FROM Option o, Vote v " +
-            "WHERE o.POLL_ID = ?1 " +
-            "AND v.OPTION_ID = o.OPTION_ID", nativeQuery = true)
-    public Iterable<Vote> findVotesByPoll(Long pollId);
+"data": [
+         ... Blog Data
+    ],
+    "totalPages": 9,
+    "currentPageNumber": 2,
+    "pageSize": 10,
+    "totalRecords": 90
 }
 ```
-
-* The custom finder method `findVotesByPoll` takes the `ID` of the `Poll` as its parameter.
-* The `@Query` annotation on this method takes a native SQL query along with the `nativeQuery` flag set to `true`.
-* At runtime, Spring Data JPA replaces the `?1` placeholder with the passed-in `pollId` parameter value.
-
-
-
-
-
-
--
-# Part 3.2.3 - Modify `VoteController`
-* Create a `getAllVotes` method in the `VoteController`
-
-
-```java
-@RequestMapping(value="/polls/{pollId}/votes", method=RequestMethod.GET)
-public Iterable<Vote> getAllVotes(@PathVariable Long pollId) {
-        return voteRepository. findByPoll(pollId);
-}
-```
-
-
-
-
-
--
--
-# Part 4 - Data Transfer Object (DTO) Implementation
-* The final piece remaining for us is the implementation of the ComputeResult resource.
-* Because we don’t have any domain objects that can directly help generate this resource representation, we implement two Data Transfer Objects or DTOs—OptionCount and VoteResult
-* Create a sub package of `java` named `dtos`
-
--
-# Part 4.1 - Create class `OptionCount`
-* The `OptionCount` DTO contains the `ID` of the option and a count of votes casted for that option.
-
-```java
-public class OptionCount {
-    private Long optionId;
-    private int count;
-
-    public Long getOptionId() {
-        return optionId;
-    }
-
-    public void setOptionId(Long optionId) {
-        this.optionId = optionId;
-    }
-
-    public int getCount() {
-        return count;
-    }
-
-    public void setCount(int count) {
-        this.count = count;
-    }
-}
-```
-
-# Part 4.2 - Create class `VoteResult`
-* The `VoteResult` DTO contains the total votes cast and a collection of `OptionCount` instances.
-
-```java
-import java.util.Collection;
-public class VoteResult {
-    private int totalVotes;
-    private Collection<OptionCount> results;
-
-    public int getTotalVotes() {
-        return totalVotes;
-    }
-
-    public void setTotalVotes(int totalVotes) {
-        this.totalVotes = totalVotes;
-    }
-
-    public Collection<OptionCount> getResults() {
-        return results;
-    }
-
-    public void setResults(Collection<OptionCount> results) {
-        this.results = results;
-    }
-}
-```
-
-
-# Part 4.3 - Create class `ComputeResultController`
-* Following the principles used in creating the `PollController` and `VoteController`, we create a new `ComputeResultController` class
-
-```java
-@RestController
-public class ComputeResultController {
-    @Inject
-    private VoteRepository voteRepository;
-
-    @RequestMapping(value = "/computeresult", method = RequestMethod.GET)
-    public ResponseEntity<?> computeResult(@RequestParam Long pollId) {
-        VoteResult voteResult = new VoteResult();
-        Iterable<Vote> allVotes = voteRepository.findVotesByPoll(pollId);
-
-        // Algorithm to count votes
-        return new ResponseEntity<VoteResult>(voteResult, HttpStatus.OK);
-    }
-```
-
-
-* We inject an instance of `VoteRepository` into the controller, which is used to retrieve votes for a given poll.
-* The `computeResult` method takes `pollId` as its parameter.
-* The `@RequestParam` annotation instructs Spring to retrieve the `pollId` value from a HTTP query parameter.
-* The computed results are sent to the client using a newly created instance of `ResponseEntity`.
-
-
-# Part 4.4 - Test via Postman
-* Start/restart the `QuickPoll` application.
-* Using the earlier Postman requests, create a poll and cast votes on its options.
-* Ensure a JSON file with a `status` of `200` is returned by executing a `GET` request of `http://localhost:8080/computeresults?pollId=1` via Postman
+* Read more about REST pagination in Spring by clicking [here](https://dzone.com/articles/rest-pagination-spring).
+
+
+-
+# Taking Action!
+
+0. Create a `src/main/resource/import.sql` file with [DML statements](http://lmgtfy.com/?q=DML+statement) for populating the database upon bootstrap. The `import.sql` should insert at least 10 polls, each with 3 or more options.
+	* Below is an example of `SQL` statements for creating a single poll with only one option.
+	
+		* Poll Creation
+		
+			```sql
+			insert into poll (poll_id, question) values (1, 'What is your favorite color?');
+			```
+		* Option Creation
+	
+			```sql
+			insert into option (option_id, option_value, poll_id) values (1, 'Red', 1);
+			``` 
+	
+0. Restart your application.
+* Ensure database is populated by `import.sql`.
+* Utilize Spring's built-in page number pagination support by researching the `PagingAndSortingRepository` class.
+* Ensure the `Controller` methods handle `Pageable` arguments.
+* Send a `GET` request to `http://localhost:8080/polls?page=0&size=2` via Postman.
+	* Ensure the response is a `JSON` object with pagination-specific information.