com.hw3dot2.BlogPostDAO.java Source code

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Here is the source code for com.hw3dot2.BlogPostDAO.java

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/*
 * Copyright (c) 2008 - 2013 10gen, Inc. <http://10gen.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.hw3dot2;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.QueryBuilder;
import org.apache.commons.lang3.StringUtils;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class BlogPostDAO {
    DBCollection postsCollection;

    public BlogPostDAO(final DB blogDatabase) {
        postsCollection = blogDatabase.getCollection("posts");
    }

    // Return a single post corresponding to a permalink
    public DBObject findByPermalink(String permalink) {

        return postsCollection.findOne(new BasicDBObject("permalink", permalink));
    }

    // Return a list of posts in descending order. Limit determines
    // how many posts are returned.

    /**
     * Return a list of DBObjects, each one a post from the posts collection
     *
     * @param limit amount of returned posts
     * @return
     */
    public List<DBObject> findByDateDescending(int limit) {

        List<DBObject> posts = new ArrayList<DBObject>();
        DBObject query = QueryBuilder.start().get();
        DBCursor cursor = postsCollection.find(query).sort(new BasicDBObject("date", -1)).limit(10);
        while (cursor.hasNext()) {
            posts.add(cursor.next());
        }
        //

        return posts;
    }

    public String addPost(String title, String body, List tags, String username) {

        System.out.println("inserting blog entry " + title + " " + body);

        String permalink = title.replaceAll("\\s", "_"); // whitespace becomes _
        permalink = permalink.replaceAll("\\W", ""); // get rid of non alphanumeric
        permalink = permalink.toLowerCase();

        BasicDBObject post = new BasicDBObject();

        if (!StringUtils.isEmpty(title) && !StringUtils.isEmpty(body) && !StringUtils.isEmpty(username)
                && (tags.size() > 0)) {
            post.append("title", title);
            post.append("author", username);
            post.append("body", body);
            post.append("permalink", permalink);
            post.append("tags", tags);
            post.append("comments", new ArrayList<DBObject>());
            post.append("date", new Date());

            postsCollection.insert(post);
        }

        // XXX HW 3.2, Work Here
        // Remember that a valid post has the following keys:
        // author, body, permalink, tags, comments, date
        //
        // A few hints:
        // - Don't forget to create an empty list of comments
        // - for the value of the date key, today's datetime is fine.
        // - tags are already in list form that implements suitable interface.
        // - we created the permalink for you above.

        // Build the post object and insert it

        return permalink;
    }

    // White space to protect the innocent

    // Append a comment to a blog post
    public void addPostComment(final String name, final String email, final String body, final String permalink) {
        BasicDBObject comment = new BasicDBObject();
        comment.append("author", name);
        if (!StringUtils.isEmpty(email)) {
            comment.append("email", email);
        }
        comment.append("body", body);
        postsCollection.update(new BasicDBObject("permalink", permalink),
                new BasicDBObject("$push", new BasicDBObject("comments", comment)));

        // XXX HW 3.3, Work Here
        // Hints:
        // - email is optional and may come in NULL. Check for that.
        // - best solution uses an update command to the database and a suitable
        //   operator to append the comment on to any existing list of comments

    }

}