Refactor article Title as Class

src/main/java/seedu/address/logic/commands/articlecommands/EditArticleCommand.java

@@ -23,6 +23,7 @@
 import seedu.address.model.article.Author;
 import seedu.address.model.article.Outlet;
 import seedu.address.model.article.Source;
+import seedu.address.model.article.Title;
 import seedu.address.model.tag.Tag;
 
 /**
@@ -91,7 +92,7 @@ public CommandResult execute(Model model) throws CommandException {
     private static Article createEditedArticle(Article articleToEdit, EditArticleDescriptor editArticleDescriptor) {
         assert articleToEdit != null;
 
-        String title = editArticleDescriptor.getTitle().orElse(articleToEdit.getTitle());
+        Title title = editArticleDescriptor.getTitle().orElse(articleToEdit.getTitle());
         Set<Author> authors = editArticleDescriptor.getAuthors().orElse(articleToEdit.getAuthors());
         Set<Source> sources = editArticleDescriptor.getSources().orElse(articleToEdit.getSources());
         Set<Tag> tags = editArticleDescriptor.getTags().orElse(articleToEdit.getTags());
@@ -134,7 +135,7 @@ public String toString() {
      */
     public static class EditArticleDescriptor {
 
-        private String title;
+        private Title title;
         private Set<Author> authors;
         private Set<Source> sources;
         private Set<Tag> tags;
@@ -164,11 +165,11 @@ public boolean isAnyFieldEdited() {
             return CollectionUtil.isAnyNonNull(title, authors, sources, outlets, publicationDate, tags, status);
         }
 
-        public void setTitle(String title) {
+        public void setTitle(Title title) {
             this.title = title;
         }
 
-        public Optional<String> getTitle() {
+        public Optional<Title> getTitle() {
             return Optional.ofNullable(title);
         }
 

src/main/java/seedu/address/logic/parser/AddArticleCommandParser.java

@@ -19,6 +19,7 @@
 import seedu.address.model.article.Author;
 import seedu.address.model.article.Outlet;
 import seedu.address.model.article.Source;
+import seedu.address.model.article.Title;
 import seedu.address.model.tag.Tag;
 
 /**
@@ -41,7 +42,7 @@ public AddArticleCommand parse(String args) throws ParseException {
             throw new ParseException(String.format(MESSAGE_INVALID_COMMAND_FORMAT, AddArticleCommand.MESSAGE_USAGE));
         }
 
-        String title = ParserUtil.parseTitle(argMultimap.getValue(PREFIX_TITLE).get());
+        Title title = ParserUtil.parseTitle(argMultimap.getValue(PREFIX_TITLE).get());
         Set<Author> authorList = ParserUtil.parseAuthors(argMultimap.getAllValues(PREFIX_AUTHOR));
         Set<Source> sourceList = ParserUtil.parseSources(argMultimap.getAllValues(PREFIX_SOURCE));
         Set<Tag> tagList = ParserUtil.parseTags(argMultimap.getAllValues(PREFIX_ARTICLETAG));

src/main/java/seedu/address/logic/parser/ParserUtil.java

@@ -20,6 +20,7 @@
 import seedu.address.model.article.Author;
 import seedu.address.model.article.Outlet;
 import seedu.address.model.article.Source;
+import seedu.address.model.article.Title;
 import seedu.address.model.person.Address;
 import seedu.address.model.person.Email;
 import seedu.address.model.person.Name;
@@ -136,11 +137,13 @@ public static Set<Tag> parseTags(Collection<String> tags) throws ParseException
     /**
      * Parses a {@code String title} into a {@code Title}.
      */
-    public static String parseTitle(String title) throws ParseException {
+    public static Title parseTitle(String title) throws ParseException {
         requireNonNull(title);
         String trimmedTitle = title.trim();
-        //removed the check for title validity
-        return trimmedTitle;
+        if (!Title.isValidTitle(trimmedTitle)) {
+            throw new ParseException(Title.MESSAGE_CONSTRAINTS);
+        }
+        return new Title(trimmedTitle);
     }
 
     /**

src/main/java/seedu/address/model/article/Article.java

@@ -16,7 +16,7 @@
  * Represents an article in the address book.
  */
 public class Article {
-    private final String title;
+    private final Title title;
     private final Set<Outlet> outlets = new HashSet<>();
     private final Set<Author> authors = new HashSet<>();
     private final Set<Source> sources = new HashSet<>();
@@ -42,7 +42,7 @@ public enum Status {
      * @param tags the subject of the article.
      * @param status the current status of the article.
      */
-    public Article(String title, Set<Author> authors, Set<Source> sources, Set<Tag> tags,
+    public Article(Title title, Set<Author> authors, Set<Source> sources, Set<Tag> tags,
                    Set<Outlet> outlets, LocalDateTime publicationDate, Status status) {
         requireAllNonNull(title, authors, sources, tags, outlets, publicationDate, status);
         this.title = title;
@@ -54,8 +54,8 @@ public Article(String title, Set<Author> authors, Set<Source> sources, Set<Tag>
         this.status = status;
     }
 
-    public String getTitle() {
-        return this.title;
+    public Title getTitle() {
+        return title;
     }
 
     public Set<Author> getAuthors() {

src/main/java/seedu/address/model/article/Title.java

@@ -0,0 +1,64 @@
+package seedu.address.model.article;
+
+import static java.util.Objects.requireNonNull;
+import static seedu.address.commons.util.AppUtil.checkArgument;
+
+/**
+ * Represents a Article's title in the address book.
+ * Guarantees: immutable; is valid as declared in {@link #isValidTitle(String)}
+ */
+public class Title implements Comparable<Title> {
+    public static final String MESSAGE_CONSTRAINTS =
+            "Titles should should not be blank or start with a whitespace character.";
+
+    public static final String VALIDATION_REGEX = "^(?!\\s).*";
+
+    public final String fullTitle;
+
+    /**
+     * Constructs a {@code Title}.
+     *
+     * @param title A valid title.
+     */
+    public Title(String title) {
+        requireNonNull(title);
+        checkArgument(isValidTitle(title), MESSAGE_CONSTRAINTS);
+        fullTitle = title;
+    }
+
+    /**
+     * Returns true if a given string is a valid title.
+     */
+    public static boolean isValidTitle(String test) {
+        return test.matches(VALIDATION_REGEX);
+    }
+
+    @Override
+    public String toString() {
+        return fullTitle;
+    }
+
+    @Override
+    public int compareTo(Title other) {
+        return this.fullTitle.compareTo(other.fullTitle);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
+        }
+
+        if (!(other instanceof Title)) {
+            return false;
+        }
+
+        Title otherTitle = (Title) other;
+        return otherTitle.fullTitle.equals(this.fullTitle);
+    }
+
+    @Override
+    public int hashCode() {
+        return fullTitle.hashCode();
+    }
+}

src/main/java/seedu/address/model/article/TitleContainsKeywordsPredicate.java

@@ -19,7 +19,7 @@ public TitleContainsKeywordsPredicate(List<String> keywords) {
     @Override
     public boolean test(Article article) {
         return keywords.stream()
-                .anyMatch(keyword -> StringUtil.containsWordIgnoreCase(article.getTitle(), keyword));
+                .anyMatch(keyword -> StringUtil.containsWordIgnoreCase(article.getTitle().fullTitle, keyword));
     }
 
     @Override

src/main/java/seedu/address/model/util/SampleArticleDataUtil.java

@@ -12,6 +12,7 @@
 import seedu.address.model.article.Author;
 import seedu.address.model.article.Outlet;
 import seedu.address.model.article.Source;
+import seedu.address.model.article.Title;
 import seedu.address.model.tag.Tag;
 
 /**
@@ -21,7 +22,8 @@ public class SampleArticleDataUtil {
 
     public static Article[] getSampleArticles() {
         return new Article[]{
-            new Article("The epitome of pain and suffering by NUS CS students.", getAuthorSet("Alice", "Bob"),
+            new Article(new Title("The epitome of pain and suffering by NUS CS students."),
+                    getAuthorSet("Alice", "Bob"),
                     getSourceSet("NUS Computing Club"), getTagSet("Student Life"), getOutletSet("SOC News Bulletin"),
                     LocalDateTime.now(), Status.PUBLISHED)
         };

src/main/java/seedu/address/storage/JsonAdaptedArticle.java

@@ -15,6 +15,7 @@
 import seedu.address.model.article.Author;
 import seedu.address.model.article.Outlet;
 import seedu.address.model.article.Source;
+import seedu.address.model.article.Title;
 import seedu.address.model.tag.Tag;
 
 /**
@@ -70,7 +71,7 @@ public JsonAdaptedArticle(@JsonProperty("title") String title,
      * @param sourceArticle
      */
     public JsonAdaptedArticle(Article sourceArticle) {
-        title = sourceArticle.getTitle();
+        title = sourceArticle.getTitle().fullTitle;
         authors.addAll(sourceArticle.getAuthors().stream()
                 .map(JsonAdaptedAuthor::new)
                 .collect(Collectors.toList()));
@@ -96,6 +97,7 @@ public Article toModelType() throws IllegalValueException {
         if (title == null) {
             throw new IllegalValueException("The title is missing");
         }
+        final Title modelTitle = new Title(title);
         if (status == null) {
             throw new IllegalValueException("The status is missing");
         }
@@ -125,6 +127,6 @@ public Article toModelType() throws IllegalValueException {
 
         final Set<Outlet> modelOutlets = new HashSet<>(articleOutlets);
 
-        return new Article(title, modelAuthors, modelSources, modelTags, modelOutlets, publicationDate, status);
+        return new Article(modelTitle, modelAuthors, modelSources, modelTags, modelOutlets, publicationDate, status);
     }
 }

src/main/java/seedu/address/ui/ArticleCard.java

@@ -53,7 +53,7 @@ public ArticleCard(Article article, int displayedIndex) {
         super(FXML);
         this.article = article;
         id.setText(displayedIndex + ". ");
-        title.setText(article.getTitle());
+        title.setText(article.getTitle().fullTitle);
 
         article.getAuthors().stream()
                 .sorted(Comparator.comparing(author -> author.authorName))