Feature/solution

src/main/java/com/scmspain/configuration/TweetConfiguration.java

@@ -2,6 +2,8 @@
 
 import com.scmspain.controller.TweetController;
 import com.scmspain.services.TweetService;
+import com.scmspain.validators.TweetValidator;
+import com.scmspain.validators.UrlRemover;
 import org.springframework.boot.actuate.metrics.writer.MetricWriter;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -10,9 +12,20 @@
 
 @Configuration
 public class TweetConfiguration {
+
+    @Bean
+    public UrlRemover getUrlRemover() {
+        return new UrlRemover();
+    }
+
+    @Bean
+    public TweetValidator getTweetValidator(UrlRemover urlRemover) {
+        return new TweetValidator(urlRemover);
+    }
+
     @Bean
-    public TweetService getTweetService(EntityManager entityManager, MetricWriter metricWriter) {
-        return new TweetService(entityManager, metricWriter);
+    public TweetService getTweetService(EntityManager entityManager, MetricWriter metricWriter, TweetValidator tweetValidator) {
+        return new TweetService(entityManager, metricWriter, tweetValidator);
     }
 
     @Bean

src/main/java/com/scmspain/controller/TweetController.java

@@ -1,14 +1,15 @@
 package com.scmspain.controller;
 
+import com.scmspain.controller.command.DiscardTweetCommand;
 import com.scmspain.controller.command.PublishTweetCommand;
 import com.scmspain.entities.Tweet;
 import com.scmspain.services.TweetService;
+import javassist.NotFoundException;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
 
-import static org.springframework.http.HttpStatus.BAD_REQUEST;
-import static org.springframework.http.HttpStatus.CREATED;
+import static org.springframework.http.HttpStatus.*;
 
 @RestController
 public class TweetController {
@@ -26,7 +27,29 @@ public List<Tweet> listAllTweets() {
     @PostMapping("/tweet")
     @ResponseStatus(CREATED)
     public void publishTweet(@RequestBody PublishTweetCommand publishTweetCommand) {
-        this.tweetService.publishTweet(publishTweetCommand.getPublisher(), publishTweetCommand.getTweet());
+        this.tweetService.publishTweet(new Tweet(publishTweetCommand.getPublisher(), publishTweetCommand.getTweet()));
+    }
+
+    @PostMapping("/discarded")
+    @ResponseStatus(OK)
+    public void discardTweet(@RequestBody DiscardTweetCommand discardTweetCommand) throws NotFoundException {
+        this.tweetService.discardTweet(discardTweetCommand.getTweet());
+    }
+
+    @GetMapping("/discarded")
+    @ResponseStatus(OK)
+    public List<Tweet> listAllDiscardedTweets() {
+        return this.tweetService.listAllDiscardedTweets();
+    }
+
+    @ExceptionHandler(NotFoundException.class)
+    @ResponseStatus(NOT_FOUND)
+    @ResponseBody
+    public Object notFoundException(NotFoundException ex) {
+        return new Object() {
+            public String message = ex.getMessage();
+            public String exceptionClass = ex.getClass().getSimpleName();
+        };
     }
 
     @ExceptionHandler(IllegalArgumentException.class)

src/main/java/com/scmspain/controller/command/DiscardTweetCommand.java

@@ -0,0 +1,14 @@
+package com.scmspain.controller.command;
+
+
+public class DiscardTweetCommand {
+    private Long tweet;
+
+    public Long getTweet() {
+        return tweet;
+    }
+
+    public void setTweet(Long tweet) {
+        this.tweet = tweet;
+    }
+}

src/main/java/com/scmspain/entities/Tweet.java

@@ -1,23 +1,43 @@
 package com.scmspain.entities;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
+import java.util.Date;
 
 @Entity
-public class Tweet {
+public final class Tweet {
     @Id
     @GeneratedValue
     private Long id;
     @Column(nullable = false)
     private String publisher;
-    @Column(nullable = false, length = 140)
+    /**
+      Todo for future versions define the limits for tweet's length and number of urls it can have
+
+      We can assume that a message including a url is not longer than 1000. This should be rethought.
+      It's more complicated than that on the real Twitter.
+      Leaving this number forever as 1000 gives opportunities for hackers trying to execute
+      time complexity attacks (see the `UrlRemover` class)
+    */
+    @Column(nullable = false, length = 1000)
     private String tweet;
     @Column (nullable=true)
     private Long pre2015MigrationStatus = 0L;
+    @JsonIgnore
+    @Column (nullable=true)
+    private Date discardDate;
 
     public Tweet() {
+
+    }
+
+    public Tweet(String publisher, String tweet) {
+        this.publisher = publisher;
+        this.tweet = tweet;
     }
 
     public Long getId() {
@@ -52,4 +72,21 @@ public void setPre2015MigrationStatus(Long pre2015MigrationStatus) {
         this.pre2015MigrationStatus = pre2015MigrationStatus;
     }
 
+    public Date getDiscardDate() {
+        return discardDate;
+    }
+
+    public void setDiscardDate(Date discardDate) {
+        this.discardDate = discardDate;
+    }
+
+    @Override
+    public String toString() {
+        return "Tweet(id=" + id +
+                ", publisher=" + publisher +
+                ", tweet=" + tweet +
+                ", discardDate=" + discardDate +
+                ")";
+    }
+
 }

src/main/java/com/scmspain/services/TweetService.java

@@ -1,6 +1,9 @@
 package com.scmspain.services;
 
 import com.scmspain.entities.Tweet;
+import com.scmspain.validators.TweetValidator;
+import javassist.NotFoundException;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.actuate.metrics.writer.Delta;
 import org.springframework.boot.actuate.metrics.writer.MetricWriter;
 import org.springframework.stereotype.Service;
@@ -9,17 +12,21 @@
 import javax.persistence.TypedQuery;
 import javax.transaction.Transactional;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Date;
 import java.util.List;
 
 @Service
 @Transactional
 public class TweetService {
     private EntityManager entityManager;
     private MetricWriter metricWriter;
+    private TweetValidator tweetValidator;
 
-    public TweetService(EntityManager entityManager, MetricWriter metricWriter) {
+    public TweetService(EntityManager entityManager, MetricWriter metricWriter, TweetValidator tweetValidator) {
         this.entityManager = entityManager;
         this.metricWriter = metricWriter;
+        this.tweetValidator = tweetValidator;
     }
 
     /**
@@ -28,19 +35,23 @@ public TweetService(EntityManager entityManager, MetricWriter metricWriter) {
       Parameter - text - Content of the Tweet
       Result - recovered Tweet
     */
-    public void publishTweet(String publisher, String text) {
-        if (publisher != null && publisher.length() > 0 && text != null && text.length() > 0 && text.length() < 140) {
-            Tweet tweet = new Tweet();
-            tweet.setTweet(text);
-            tweet.setPublisher(publisher);
-
+    public void publishTweet(Tweet tweet) {
+        if (tweetValidator.isValid(tweet)) {
             this.metricWriter.increment(new Delta<Number>("published-tweets", 1));
             this.entityManager.persist(tweet);
-        } else {
-            throw new IllegalArgumentException("Tweet must not be greater than 140 characters");
         }
     }
 
+    public void discardTweet(Long tweetId) throws NotFoundException {
+        Tweet tweet = getTweet(tweetId);
+        if (tweet == null)
+            throw new NotFoundException("The tweet id does not match any tweet");
+        tweet.setDiscardDate(new Date());
+        this.metricWriter.increment(new Delta<Number>("discarded-tweets", 1));
+        this.entityManager.persist(tweet);
+    }
+
+
     /**
       Recover tweet from repository
       Parameter - id - id of the Tweet to retrieve
@@ -58,11 +69,23 @@ public Tweet getTweet(Long id) {
     public List<Tweet> listAllTweets() {
         List<Tweet> result = new ArrayList<Tweet>();
         this.metricWriter.increment(new Delta<Number>("times-queried-tweets", 1));
-        TypedQuery<Long> query = this.entityManager.createQuery("SELECT id FROM Tweet AS tweetId WHERE pre2015MigrationStatus<>99 ORDER BY id DESC", Long.class);
+        TypedQuery<Long> query = this.entityManager.createQuery("SELECT id FROM Tweet AS tweetId WHERE discardDate is null and pre2015MigrationStatus<>99 ORDER BY id DESC", Long.class);
         List<Long> ids = query.getResultList();
         for (Long id : ids) {
             result.add(getTweet(id));
         }
         return result;
     }
+
+    public List<Tweet> listAllDiscardedTweets() {
+        List<Tweet> result = new ArrayList<>();
+        this.metricWriter.increment(new Delta<Number>("times-queried-discarded-tweets", 1));
+        TypedQuery<Long> query = this.entityManager.createQuery("SELECT id FROM Tweet AS tweetId WHERE discardDate is not null and pre2015MigrationStatus<>99 ORDER BY discardDate DESC", Long.class);
+        List<Long> ids = query.getResultList();
+        for (Long id : ids) {
+            Tweet t = getTweet(id);
+            result.add(t);
+        }
+        return result;
+    }
 }

src/main/java/com/scmspain/validators/TweetValidator.java

@@ -0,0 +1,27 @@
+package com.scmspain.validators;
+
+import com.scmspain.entities.Tweet;
+import org.springframework.stereotype.Component;
+
+@Component
+public class TweetValidator {
+
+    private UrlRemover urlRemover;
+
+    public TweetValidator(UrlRemover urlRemover) {
+        this.urlRemover = urlRemover;
+    }
+
+    public boolean isValid(Tweet t) {
+        String tweetText = t.getTweet();
+        if (tweetText == null  || tweetText.length() == 0)
+            throw new IllegalArgumentException("Tweet should not be empty.");
+        String textWithoutUrls = urlRemover.getTextWithoutUrls(tweetText);
+        if (140 < textWithoutUrls.length())
+            throw new IllegalArgumentException("Tweet should have at most 140 characters.");
+        else if (t.getPublisher() == null || t.getPublisher().length() == 0)
+            throw new IllegalArgumentException("Publisher should not be empty.");
+        else
+            return true;
+    }
+}

src/main/java/com/scmspain/validators/UrlRemover.java

@@ -0,0 +1,24 @@
+package com.scmspain.validators;
+
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+
+@Component
+public class UrlRemover {
+
+    public String getTextWithoutUrls(String text) {
+        String urlRegex = "((https?)://+[\\w\\d:#@%/;$()~_?\\+-=\\\\\\.&]*)";
+        String result = text.replaceAll(urlRegex, "");
+        return result;
+    }
+
+
+    // Todo make sure hackers don't send messages with hundreds of short links
+    String removeUrls(String s, List<String> urls) {
+        String result = s;
+        for (String url: urls)
+            result = result.replace(url, "");
+        return result;
+    }
+}