Java implementation of: WTF is a SuperColumn? An Intro to the Cassandra Data Model

After reading WTF is a SuperColumn? An Intro to the Cassandra Data Model I decided to implement, in Java, a client to insert and read data to the data model presented.

<Keyspace Name="BloggyAppy">
 <KeysCachedFraction>0.01</KeysCachedFraction>
 <ColumnFamily CompareWith="BytesType" Name="Authors"/>
 <ColumnFamily CompareWith="BytesType" Name="BlogEntries"/>
 <ColumnFamily CompareWith="TimeUUIDType" Name="TaggedPosts"/>
 <ColumnFamily CompareWith="TimeUUIDType" Name="Comments"
  CompareSubcolumnsWith="BytesType" ColumnType="Super"/>
</Keyspace>

Data model used

For simplicity I removed some columns of the column families and created the following Java domain classes.

package domain; public class Author {   public Author(String username, String email) {     this.username = username;     this.email = email;   }   public String getUsername() {     return username;   }   public void setUsername(String username) {     this.username = username;   }   public String getEmail() {     return email;   }   public void setEmail(String email) {     this.email = email;   }   public int getTotalPosts() {     return totalPosts;   }   public void setTotalPosts(int totalPosts) {     this.totalPosts = totalPosts;   }   private String username;   private String email;   private int totalPosts; }

package domain; import java.util.ArrayList; public class BlogEntry {   public BlogEntry() {     this.tag.add(new Tag("__notag__"));   }   public String getSlug() {     return slug;   }   public void setSlug(String slug) {     this.slug = slug;   }   public Author getAuthor() {     return author;   }   public void setAuthor(Author author) {     this.author = author;   }   public String getBody() {     return body;   }   public void setBody(String body) {     this.body = body;   }   public ArrayList<Tag> getTag() {     return (ArrayList<Tag>) tag.clone();   }   public String getTitle() {     return title;   }   public void setTitle(String title) {     this.title = title;   }   public void addTag(Tag tag) {     if (!this.tag.contains(tag)) {       this.tag.add(tag);     }   }   private String slug;   private Author author;   private String body;   private ArrayList<Tag> tag = new ArrayList<Tag>();;   private String title; }

package domain; public class Comment {   public Comment(String commenter, String comment) {     this.commenter = commenter;     this.comment = comment;   }   public String getCommenter() {     return commenter;   }   public void setCommenter(String commenter) {     this.commenter = commenter;   }   public String getComment() {     return comment;   }   public void setComment(String comment) {     this.comment = comment;   }   private String commenter;   private String comment; }

package domain; public class Tag {   public Tag(String name) {     this.name = name;   }   public boolean equals(Object obj) {     return this.name.equals(((Tag) obj).getName());   }   public int hashCode() {     return this.name.hashCode();   }   public String getName() {     return this.name;   }   private String name; }

package client; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.cassandra.service.Cassandra; import org.apache.cassandra.service.Column; import org.apache.cassandra.service.ColumnOrSuperColumn; import org.apache.cassandra.service.ColumnParent; import org.apache.cassandra.service.ColumnPath; import org.apache.cassandra.service.ConsistencyLevel; import org.apache.cassandra.service.SlicePredicate; import org.apache.cassandra.service.SliceRange; import org.apache.cassandra.service.SuperColumn; import org.apache.thrift.protocol.TBinaryProtocol; import org.apache.thrift.protocol.TProtocol; import org.apache.thrift.transport.TSocket; import org.apache.thrift.transport.TTransport; import org.safehaus.uuid.UUID; import org.safehaus.uuid.UUIDGenerator; import domain.Author; import domain.BlogEntry; import domain.Comment; import domain.Tag; public class BlogClient {   private static void readEntireRowAuthor(Cassandra.Client client,       Author author) throws Exception {     SlicePredicate predicate = new SlicePredicate(null, new SliceRange(         new byte[0], new byte[0], false, 10));     ColumnParent parent = new ColumnParent("Authors", null);     List<ColumnOrSuperColumn> results = client.get_slice("BloggyAppy",         author.getUsername(), parent, predicate, ConsistencyLevel.ONE);     for (ColumnOrSuperColumn result : results) {       Column column = result.column;       System.out.println(new String(column.name, "UTF-8") + " -> "           + new String(column.value, "UTF-8"));     }   }   private static void readEntireRowBlogEntry(Cassandra.Client client,       String slug) throws Exception {     SlicePredicate predicate = new SlicePredicate(null, new SliceRange(         new byte[0], new byte[0], false, 10));     ColumnParent parent = new ColumnParent("BlogEntries", null);     List<ColumnOrSuperColumn> results = client.get_slice("BloggyAppy",         slug, parent, predicate, ConsistencyLevel.ONE);     for (ColumnOrSuperColumn result : results) {       Column column = result.column;       System.out.println(new String(column.name, "UTF-8") + " -> "           + new String(column.value, "UTF-8"));     }   }   private static void readEntireRowTaggedPost(Cassandra.Client client,       String tag) throws Exception {     SlicePredicate predicate = new SlicePredicate(null, new SliceRange(         new byte[0], new byte[0], false, 10));     ColumnParent parent = new ColumnParent("TaggedPosts", null);     List<ColumnOrSuperColumn> results = client.get_slice("BloggyAppy", tag,         parent, predicate, ConsistencyLevel.ONE);     for (ColumnOrSuperColumn result : results) {       Column column = result.column;       UUID uuid = new UUID(column.name);       System.out.println(uuid.toString() + " -> "           + new String(column.value, "UTF-8"));     }   }   private static void readEntireRowComment(Cassandra.Client client,       BlogEntry blogEntry) throws Exception {     SlicePredicate predicate = new SlicePredicate(null, new SliceRange(         new byte[0], new byte[0], false, 10));     ColumnParent parent = new ColumnParent("Comments", null);     List<ColumnOrSuperColumn> results = client.get_slice("BloggyAppy",         blogEntry.getSlug(), parent, predicate, ConsistencyLevel.ONE);     for (ColumnOrSuperColumn result : results) {       SuperColumn superColumn = result.super_column;       UUID uuid = new UUID(superColumn.name);       System.out.println(uuid.toString() + " -> ");       for (Column column : superColumn.columns) {         System.out.println("\t" + new String(column.name, "UTF-8")             + " -> " + new String(column.value, "UTF-8"));       }     }   }   private static void readSingleColumnAuthor(Cassandra.Client client,       Author author) throws Exception {     ColumnPath path = new ColumnPath("Authors", null, "email"         .getBytes("UTF-8"));     ColumnOrSuperColumn colOrSupCol = client.get("BloggyAppy", author         .getUsername(), path, ConsistencyLevel.ONE);     Column column = colOrSupCol.getColumn();     System.out.println(colOrSupCol);     System.out.println("name:" + new String(column.getName()));     System.out.println("value:" + new String(column.getValue()));   }   private static void insertAuthor(Cassandra.Client client, Author author)       throws Exception {     long timestamp = System.currentTimeMillis();     client.insert("BloggyAppy", author.getUsername(), new ColumnPath(         "Authors", null, "email".getBytes("UTF-8")), author.getEmail()         .getBytes("UTF-8"), timestamp, ConsistencyLevel.ONE);     client.insert("BloggyAppy", author.getUsername(), new ColumnPath(         "Authors", null, "totalPosts".getBytes("UTF-8")), Integer         .toString(author.getTotalPosts()).getBytes("UTF-8"), timestamp,         ConsistencyLevel.ONE);   }   private static void insertBlogEntry(Cassandra.Client client,       BlogEntry blogEntry) throws Exception {     long timestamp = System.currentTimeMillis();     client.insert("BloggyAppy", blogEntry.getSlug(), new ColumnPath(         "BlogEntries", null, "author".getBytes("UTF-8")), blogEntry         .getAuthor().getUsername().getBytes("UTF-8"), timestamp,         ConsistencyLevel.ONE);     client.insert("BloggyAppy", blogEntry.getSlug(), new ColumnPath(         "BlogEntries", null, "body".getBytes("UTF-8")), blogEntry         .getBody().getBytes("UTF-8"), timestamp, ConsistencyLevel.ONE);     client.insert("BloggyAppy", blogEntry.getSlug(), new ColumnPath(         "BlogEntries", null, "title".getBytes("UTF-8")), blogEntry         .getTitle().getBytes("UTF-8"), timestamp, ConsistencyLevel.ONE);     StringBuilder sb = new StringBuilder();     for (Tag tag : blogEntry.getTag()) {       sb.append(tag.getName());       sb.append(" ");     }     client.insert("BloggyAppy", blogEntry.getSlug(), new ColumnPath(         "BlogEntries", null, "tags".getBytes("UTF-8")), sb.toString()         .trim().getBytes("UTF-8"), timestamp, ConsistencyLevel.ONE);   }   private static void insertTaggedPost(Cassandra.Client client, String tag,       BlogEntry blogEntry) throws Exception {     long timestamp = System.currentTimeMillis();     UUID uu = UUIDGenerator.getInstance().generateTimeBasedUUID();     client.insert("BloggyAppy", tag, new ColumnPath("TaggedPosts", null, uu         .toByteArray()), blogEntry.getSlug().getBytes("UTF-8"),         timestamp, ConsistencyLevel.ONE);   }   private static void insertComment(Cassandra.Client client,       BlogEntry blogEntry, Comment comment) throws Exception {     long timestamp = System.currentTimeMillis();     UUID uuid = UUIDGenerator.getInstance().generateTimeBasedUUID();     Column colCommenter = new Column("commenter".getBytes("UTF-8"), comment         .getCommenter().getBytes("UTF-8"), timestamp);     Column colComment = new Column("comment".getBytes("UTF-8"), comment         .getComment().getBytes("UTF-8"), timestamp);     SuperColumn s = new SuperColumn();     s.name = uuid.toByteArray();     s.addToColumns(colCommenter);     s.addToColumns(colComment);     ColumnOrSuperColumn csc = new ColumnOrSuperColumn();     csc.super_column = s;     List<ColumnOrSuperColumn> columns = new ArrayList<ColumnOrSuperColumn>();     columns.add(csc);     Map<String, List<ColumnOrSuperColumn>> superCol =        new HashMap<String, List<ColumnOrSuperColumn>>();     superCol.put("Comments", columns);     client.batch_insert("BloggyAppy", blogEntry.getSlug(), superCol,         ConsistencyLevel.ONE);   }   public static void main(String[] args) throws Exception {     TTransport trA = new TSocket("serverA", 9160);     TProtocol protoA = new TBinaryProtocol(trA);     Cassandra.Client clientA = new Cassandra.Client(protoA);     trA.open();     TTransport trB = new TSocket("serverB", 9160);     TProtocol protoB = new TBinaryProtocol(trB);     Cassandra.Client clientB = new Cassandra.Client(protoB);     trB.open();     // insert data     Author author = new Author("pedro", "pedro@yahoo.com");     author.setTotalPosts(0);     // insertAuthor(clientA, author);     // readSingleColumnAuthor(client, author);     readEntireRowAuthor(clientB, author);     BlogEntry blogEntry = new BlogEntry();     blogEntry.setAuthor(author);     blogEntry.setBody("Este es el cuerpo del post de testeo.");     blogEntry.setSlug("post-de-testeo");     blogEntry.addTag(new Tag("test"));     blogEntry.addTag(new Tag("post"));     blogEntry.setTitle("Post de testeo");     // insertBlogEntry(client, blogEntry);     // readEntireRowBlogEntry(client, blogEntry.getSlug());     // insertTaggedPost(client, "test", blogEntry);     // insertTaggedPost(client, "__notag__", blogEntry);     // readEntireRowTaggedPost(client, "test");     // readEntireRowTaggedPost(client, "__notag__");     // Comment comment = new Comment("Pedro Marini", "El post lo veo bien");     // Comment comment = new Comment("Lolo Grep",     // "Para cuando lo esta listo?");     // insertComment(client, blogEntry, comment);     // readEntireRowComment(clientA, blogEntry);     trA.close();     trB.close();   } }