Merge pull request #3861 from aurasphere/BAEL-1591-mongodb-tagging

Bael 1591 mongodb tagging

persistence-modules/java-mongodb/src/main/java/com/baeldung/tagging/Post.java

@@ -0,0 +1,172 @@
+package com.baeldung.tagging;
+
+import java.util.List;
+
+/**
+ * Model for a blog post.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class Post {
+
+	/**
+	 * Title of the post. Must be unique.
+	 */
+	private String title;
+
+	/**
+	 * Full article.
+	 */
+	private String article;
+
+	/**
+	 * Author of the post.
+	 */
+	private String author;
+
+	/**
+	 * Tags of the post.
+	 */
+	private List<String> tags;
+
+	/**
+	 * Gets the {@link #title}.
+	 *
+	 * @return the {@link #title}
+	 */
+	public String getTitle() {
+		return title;
+	}
+
+	/**
+	 * Sets the {@link #title}.
+	 *
+	 * @param title
+	 *            the new {@link #title}
+	 */
+	public void setTitle(String title) {
+		this.title = title;
+	}
+
+	/**
+	 * Gets the {@link #article}.
+	 *
+	 * @return the {@link #article}
+	 */
+	public String getArticle() {
+		return article;
+	}
+
+	/**
+	 * Sets the {@link #article}.
+	 *
+	 * @param article
+	 *            the new {@link #article}
+	 */
+	public void setArticle(String article) {
+		this.article = article;
+	}
+
+	/**
+	 * Gets the {@link #author}.
+	 *
+	 * @return the {@link #author}
+	 */
+	public String getAuthor() {
+		return author;
+	}
+
+	/**
+	 * Sets the {@link #author}.
+	 *
+	 * @param author
+	 *            the new {@link #author}
+	 */
+	public void setAuthor(String author) {
+		this.author = author;
+	}
+
+	/**
+	 * Gets the {@link #tags}.
+	 *
+	 * @return the {@link #tags}
+	 */
+	public List<String> getTags() {
+		return tags;
+	}
+
+	/**
+	 * Sets the {@link #tags}.
+	 *
+	 * @param tags
+	 *            the new {@link #tags}
+	 */
+	public void setTags(List<String> tags) {
+		this.tags = tags;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((article == null) ? 0 : article.hashCode());
+		result = prime * result + ((author == null) ? 0 : author.hashCode());
+		result = prime * result + ((tags == null) ? 0 : tags.hashCode());
+		result = prime * result + ((title == null) ? 0 : title.hashCode());
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Post other = (Post) obj;
+		if (article == null) {
+			if (other.article != null)
+				return false;
+		} else if (!article.equals(other.article))
+			return false;
+		if (author == null) {
+			if (other.author != null)
+				return false;
+		} else if (!author.equals(other.author))
+			return false;
+		if (tags == null) {
+			if (other.tags != null)
+				return false;
+		} else if (!tags.equals(other.tags))
+			return false;
+		if (title == null) {
+			if (other.title != null)
+				return false;
+		} else if (!title.equals(other.title))
+			return false;
+		return true;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return "Post [title=" + title + ", article=" + article + ", author=" + author + ", tags=" + tags + "]";
+	}
+
+}

persistence-modules/java-mongodb/src/main/java/com/baeldung/tagging/TagRepository.java

@@ -0,0 +1,154 @@
+package com.baeldung.tagging;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import org.bson.Document;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBCollection;
+import com.mongodb.MongoClient;
+import com.mongodb.client.FindIterable;
+import com.mongodb.client.MongoCollection;
+import com.mongodb.client.MongoDatabase;
+import com.mongodb.client.model.Filters;
+import com.mongodb.client.model.Updates;
+import com.mongodb.client.result.UpdateResult;
+
+/**
+ * Repository used to manage tags for a blog post.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class TagRepository implements Closeable {
+
+	/**
+	 * Document field which holds the blog tags.
+	 */
+	private static final String TAGS_FIELD = "tags";
+
+	/**
+	 * The post collection.
+	 */
+	private MongoCollection<Document> collection;
+
+	/**
+	 * The MongoDB client, stored in a field in order to close it later.
+	 */
+	private MongoClient mongoClient;
+
+	/**
+	 * Instantiates a new TagRepository by opening the DB connection.
+	 */
+	public TagRepository() {
+		mongoClient = new MongoClient("localhost", 27018);
+		MongoDatabase database = mongoClient.getDatabase("blog");
+		collection = database.getCollection("posts");
+	}
+
+	/**
+	 * Returns a list of posts which contains one or more of the tags passed as
+	 * argument.
+	 * 
+	 * @param tags
+	 *            a list of tags
+	 * @return a list of posts which contains at least one of the tags passed as
+	 *         argument
+	 */
+	public List<Post> postsWithAtLeastOneTag(String... tags) {
+		FindIterable<Document> results = collection.find(Filters.in(TAGS_FIELD, tags));
+		return StreamSupport.stream(results.spliterator(), false).map(TagRepository::documentToPost)
+				.collect(Collectors.toList());
+	}
+
+	/**
+	 * Returns a list of posts which contains all the tags passed as argument.
+	 * 
+	 * @param tags
+	 *            a list of tags
+	 * @return a list of posts which contains all the tags passed as argument
+	 */
+	public List<Post> postsWithAllTags(String... tags) {
+		FindIterable<Document> results = collection.find(Filters.all(TAGS_FIELD, tags));
+		return StreamSupport.stream(results.spliterator(), false).map(TagRepository::documentToPost)
+				.collect(Collectors.toList());
+	}
+
+	/**
+	 * Returns a list of posts which contains none of the tags passed as
+	 * argument.
+	 * 
+	 * @param tags
+	 *            a list of tags
+	 * @return a list of posts which contains none of the tags passed as
+	 *         argument
+	 */
+	public List<Post> postsWithoutTags(String... tags) {
+		FindIterable<Document> results = collection.find(Filters.nin(TAGS_FIELD, tags));
+		return StreamSupport.stream(results.spliterator(), false).map(TagRepository::documentToPost)
+				.collect(Collectors.toList());
+	}
+
+	/**
+	 * Adds a list of tags to the blog post with the given title.
+	 * 
+	 * @param title
+	 *            the title of the blog post
+	 * @param tags
+	 *            a list of tags to add
+	 * @return the outcome of the operation
+	 */
+	public boolean addTags(String title, List<String> tags) {
+		UpdateResult result = collection.updateOne(new BasicDBObject(DBCollection.ID_FIELD_NAME, title),
+				Updates.addEachToSet(TAGS_FIELD, tags));
+		return result.getModifiedCount() == 1;
+	}
+
+	/**
+	 * Removes a list of tags to the blog post with the given title.
+	 * 
+	 * @param title
+	 *            the title of the blog post
+	 * @param tags
+	 *            a list of tags to remove
+	 * @return the outcome of the operation
+	 */
+	public boolean removeTags(String title, List<String> tags) {
+		UpdateResult result = collection.updateOne(new BasicDBObject(DBCollection.ID_FIELD_NAME, title),
+				Updates.pullAll(TAGS_FIELD, tags));
+		return result.getModifiedCount() == 1;
+	}
+
+	/**
+	 * Utility method used to map a MongoDB document into a {@link Post}.
+	 * 
+	 * @param document
+	 *            the document to map
+	 * @return a {@link Post} object equivalent to the document passed as
+	 *         argument
+	 */
+	@SuppressWarnings("unchecked")
+	private static Post documentToPost(Document document) {
+		Post post = new Post();
+		post.setTitle(document.getString(DBCollection.ID_FIELD_NAME));
+		post.setArticle(document.getString("article"));
+		post.setAuthor(document.getString("author"));
+		post.setTags((List<String>) document.get(TAGS_FIELD));
+		return post;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.io.Closeable#close()
+	 */
+	@Override
+	public void close() throws IOException {
+		mongoClient.close();
+	}
+
+}

persistence-modules/java-mongodb/src/test/java/com/baeldung/tagging/TaggingIntegrationTest.java

@@ -0,0 +1,177 @@
+package com.baeldung.tagging;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.StreamSupport;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test for {@link TagRepository}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class TaggingIntegrationTest {
+
+	/**
+	 * Object to test.
+	 */
+	private TagRepository repository;
+
+	/**
+	 * Sets the test up by instantiating the object to test.
+	 */
+	@Before
+	public void setup() {
+		repository = new TagRepository();
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithAtLeastOneTag(String...)} with 1 tag.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithAtLeastOneTagMongoDB_then3Results() {
+		List<Post> results = repository.postsWithAtLeastOneTag("MongoDB");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(3, results.size());
+		results.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("MongoDB"));
+		});
+
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithAtLeastOneTag(String...)} with 2
+	 * tags.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithAtLeastOneTagMongoDBJava8_then4Results() {
+		List<Post> results = repository.postsWithAtLeastOneTag("MongoDB", "Java 8");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(4, results.size());
+		results.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("MongoDB") || post.getTags().contains("Java 8"));
+		});
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithAllTags(String...)} with 1 tag.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithAllTagsMongoDB_then3Results() {
+		List<Post> results = repository.postsWithAllTags("MongoDB");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(3, results.size());
+		results.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("MongoDB"));
+		});
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithAllTags(String...)} with 2 tags.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithAllTagsMongoDBJava8_then2Results() {
+		List<Post> results = repository.postsWithAllTags("MongoDB", "Java 8");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(2, results.size());
+		results.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("MongoDB"));
+			Assert.assertTrue(post.getTags().contains("Java 8"));
+		});
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithoutTags(String...)} with 1 tag.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithoutTagsMongoDB_then1Result() {
+		List<Post> results = repository.postsWithoutTags("MongoDB");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(1, results.size());
+		results.forEach(post -> {
+			Assert.assertFalse(post.getTags().contains("MongoDB"));
+		});
+	}
+
+	/**
+	 * Tests {@link TagRepository#postsWithoutTags(String...)} with 2 tags.
+	 */
+	@Test
+	public void givenTagRepository_whenPostsWithoutTagsMongoDBJava8_then0Results() {
+		List<Post> results = repository.postsWithoutTags("MongoDB", "Java 8");
+		results.forEach(System.out::println);
+
+		Assert.assertEquals(0, results.size());
+		results.forEach(post -> {
+			Assert.assertFalse(post.getTags().contains("MongoDB"));
+			Assert.assertFalse(post.getTags().contains("Java 8"));
+		});
+	}
+
+	/**
+	 * Tests {@link TagRepository#addTags(String, List)} and
+	 * {@link TagRepository#removeTags(String, List)}. These tests run together
+	 * to keep the database in a consistent state.
+	 */
+	@Test
+	public void givenTagRepository_whenAddingRemovingElements_thenNoDuplicates() {
+		// Adds one element and checks the result.
+		boolean result = repository.addTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertTrue(result);
+
+		// We add the same elements again to check that there's no duplication.
+		result = repository.addTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertFalse(result);
+
+		// Fetches the element back to check if the elements have been added.
+		List<Post> postsAfterAddition = repository.postsWithAllTags("jUnit", "jUnit5");
+		Assert.assertEquals(1, postsAfterAddition.size());
+		postsAfterAddition.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("jUnit"));
+			Assert.assertTrue(post.getTags().contains("jUnit5"));
+		});
+
+		// Checks for duplication.
+		long countDuplicateTags = StreamSupport.stream(postsAfterAddition.get(0).getTags().spliterator(), false)
+				.filter(x -> x.equals("jUnit5")).count();
+		Assert.assertEquals(1, countDuplicateTags);
+
+		// Tries to remove the tags added.
+		result = repository.removeTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertTrue(result);
+
+		// We remove the same elements again to check for errors.
+		result = repository.removeTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertFalse(result);
+
+		// Fetches the element back to check if the elements have been removed.
+		List<Post> postsAfterDeletion = repository.postsWithAllTags("jUnit", "jUnit5");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+		postsAfterDeletion = repository.postsWithAtLeastOneTag("jUnit");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+		postsAfterDeletion = repository.postsWithAtLeastOneTag("jUnit5");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+	}
+
+	/**
+	 * Cleans up the test by deallocating memory.
+	 * 
+	 * @throws IOException
+	 */
+	@After
+	public void teardown() throws IOException {
+		repository.close();
+	}
+
+}