Abdullah/distributed

src/main/java/model/codec/EncodedEntity.java

@@ -1,18 +1,54 @@
 package model.codec;
 
+import java.io.Serializable;
+import java.util.Arrays;
+
 /**
  * Represents an encapsulation around the byte representation of an entity accompanied by its original type.
  */
-public class EncodedEntity {
+public class EncodedEntity implements Serializable {
   private final byte[] bytes;
   private final String type;
 
-  // EncodedEntity(id.getBytes() || byte(i), "assignment")
+  /**
+   * Creates encoded entity.
+   *
+   * @param bytes bytes of entity.
+   * @param type types of entity.
+   */
   public EncodedEntity(byte[] bytes, String type) {
     this.bytes = bytes.clone();
     this.type = type;
   }
 
+  /**
+   * Hashcode of entity.
+   *
+   * @return hashcode of encodedentity.
+   */
+  @Override
+  public int hashCode() {
+    return Arrays.hashCode(this.bytes);
+  }
+
+  /**
+   * Check if objects are equal.
+   *
+   * @param o encodedentity.
+   * @return true if equals.
+   */
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof EncodedEntity)) {
+      return false;
+    }
+    EncodedEntity that = (EncodedEntity) o;
+    return Arrays.equals(this.bytes, that.bytes);
+  }
+
   public byte[] getBytes() {
     return bytes.clone();
   }

src/main/java/model/crypto/Sha3256Hash.java

@@ -1,5 +1,6 @@
 package model.crypto;
 
+import java.io.Serializable;
 import java.util.Arrays;
 
 import model.lightchain.Identifier;
@@ -8,7 +9,7 @@
  * Represents SHA3-256 data type which extends abstract Hash data type for
  * the cryptographic hash function used in LightChain.
  */
-public class Sha3256Hash extends Hash {
+public class Sha3256Hash extends Hash implements Serializable {
   public static final int Size = 32;
   private final byte[] hashBytes;
 

src/main/java/model/crypto/Signature.java

@@ -30,4 +30,5 @@ public Identifier getSignerId() {
   public byte[] getBytes() {
     return bytes.clone();
   }
+
 }

src/main/java/storage/Distributed.java

@@ -3,7 +3,7 @@
 import java.util.ArrayList;
 
 import model.Entity;
-import model.lightchain.Block;
+import model.exceptions.CodecException;
 import model.lightchain.Identifier;
 
 /**
@@ -26,7 +26,7 @@ public interface Distributed {
    * @return true if entity did not exist on the database, false if entity is already in
    * database.
    */
-  boolean add(Entity e);
+  boolean add(Entity e) throws CodecException;
 
   /**
    * Removes entity with given identifier.
@@ -35,20 +35,20 @@ public interface Distributed {
    * @return true if entity exists on database and removed successfully, false if entity does not exist on
    * database.
    */
-  boolean remove(Entity e);
+  boolean remove(Entity e) throws CodecException;
 
   /**
    * Returns the entity with given identifier.
    *
    * @param e identifier of the entity.
    * @return the entity itself if exists and null otherwise.
    */
-  Block get(Identifier e);
+  Entity get(Identifier e) throws CodecException;
 
   /**
    * Returns all entities stored in database.
    *
    * @return all stored entities in database.
    */
-  ArrayList<Entity> all();
+  ArrayList<Entity> all() throws CodecException;
 }

src/main/java/storage/mapdb/DistributedMapDb.java

@@ -0,0 +1,151 @@
+package storage.mapdb;
+
+import java.util.ArrayList;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import model.Entity;
+import model.codec.EncodedEntity;
+import model.exceptions.CodecException;
+import model.lightchain.Identifier;
+import modules.codec.JsonEncoder;
+import org.mapdb.DB;
+import org.mapdb.DBMaker;
+import org.mapdb.HTreeMap;
+import org.mapdb.Serializer;
+
+/**
+ * Distributed databese that store encoded entities.
+ */
+public class DistributedMapDb implements storage.Distributed {
+
+  private final DB db;
+  private final ReentrantReadWriteLock lock;
+  private static final String MAP_NAME = "distributed_map";
+  private final HTreeMap distributedMap;
+
+  /**
+   * Creates DistributedMapDb.
+   */
+  public DistributedMapDb(String filePath) {
+    this.db = DBMaker.fileDB(filePath).make();
+    this.lock = new ReentrantReadWriteLock();
+    distributedMap = this.db.hashMap(MAP_NAME)
+        .keySerializer(Serializer.BYTE_ARRAY)
+        .createOrOpen();
+  }
+
+  /**
+   * Checks existence of entity on the database.
+   *
+   * @param entityId Identifier of entity.
+   * @return true if a entity with that identifier exists, false otherwise.
+   */
+  @Override
+  public boolean has(Identifier entityId) {
+    boolean hasBoolean;
+    try {
+      lock.readLock().lock();
+      hasBoolean = distributedMap.containsKey(entityId.getBytes());
+    } finally {
+      lock.readLock().unlock();
+    }
+    return hasBoolean;
+  }
+
+  /**
+   * Adds entity to the database.
+   *
+   * @param e given entity to be added.
+   * @return true if entity did not exist on the database, false if entity is already in
+   * database.
+   */
+  @Override
+  public boolean add(Entity e) throws CodecException {
+    JsonEncoder encoder = new JsonEncoder();
+    boolean addBoolean;
+    try {
+      lock.writeLock().lock();
+      addBoolean = distributedMap.putIfAbsentBoolean(e.id().getBytes(), encoder.encode(e));
+    } catch (CodecException ex) {
+      throw new CodecException("could not encode the entity", ex);
+    } finally {
+      lock.writeLock().unlock();
+    }
+    return addBoolean;
+  }
+
+  /**
+   * Removes entity with given identifier.
+   *
+   * @param e identifier of the entity.
+   * @return true if entity exists on database and removed successfully, false if entity does not exist on
+   * database.
+   */
+  @Override
+  public boolean remove(Entity e) throws CodecException {
+    JsonEncoder encoder = new JsonEncoder();
+    boolean removeBoolean;
+    try {
+      lock.writeLock().lock();
+      removeBoolean = distributedMap.remove(e.id().getBytes(), encoder.encode(e));
+    } catch (CodecException exception) {
+      throw new CodecException("could not encode entity", exception);
+    } finally {
+      lock.writeLock().unlock();
+    }
+    return removeBoolean;
+  }
+
+  /**
+   * Returns the entity with given identifier.
+   *
+   * @param entityId identifier of the entity.
+   * @return the entity itself if exists and null otherwise.
+   */
+  @Override
+  public Entity get(Identifier entityId) throws CodecException {
+
+    Entity decodedEntity;
+
+    try {
+      JsonEncoder encoder = new JsonEncoder();
+      lock.readLock().lock();
+      EncodedEntity encodedEntity = (EncodedEntity) distributedMap.get(entityId.getBytes());
+      if (encodedEntity == null) {
+        return null;
+      }
+      decodedEntity = encoder.decode(encodedEntity);
+    } catch (CodecException e) {
+      throw new CodecException("could not found the class", e);
+    } finally {
+      lock.readLock().unlock();
+    }
+    return decodedEntity;
+  }
+
+  /**
+   * Returns all entities stored in database.
+   *
+   * @return all stored entities in database.
+   */
+  @Override
+  public ArrayList<Entity> all() throws CodecException {
+    JsonEncoder encoder = new JsonEncoder();
+    ArrayList<Entity> allEntities = new ArrayList<>();
+    for (Object encodedEntity : distributedMap.values()) {
+      try {
+        allEntities.add(encoder.decode((EncodedEntity) encodedEntity));
+      } catch (CodecException e) {
+        throw new CodecException("could not found the class", e);
+      }
+    }
+    return allEntities;
+  }
+
+  /**
+   * It closes the database.
+   */
+  public void closeDb() {
+    db.close();
+  }
+}

src/test/java/modules/JsonEncoderTest.java

@@ -18,7 +18,7 @@ public class JsonEncoderTest {
   @Test
   public void testEncodingRoundTrip() throws CodecException {
     JsonEncoder encoder = new JsonEncoder();
-    EntityFixture entity = new EntityFixture();
+    Entity entity = new EntityFixture();
     Entity entityChanged = encoder.decode(encoder.encode(entity));
     Assertions.assertEquals(entity, entityChanged);
   }