Package io.pmem.pmemkv

Class Database<K,​V>

  • Type Parameters:
    K - the type of key stored in pmemkv datastore
    V - the type of value stored in pmemkv datastore
    public class Database<K,​V>
extends Object
    Main Java binding pmemkv class, which is a local/embedded key-value datastore optimized for persistent memory. Rather than being tied to a single language or backing implementation, pmemkv provides different options for language bindings and storage engines.

    This generic class allows to store data of any type (as both key and value). In most cases user needs to implement Converter interface, which provides functionality of converting between key and value types, and ByteBuffer.

    See Also:
    Pmemkv

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  Database.Builder<K,​V>
      Builder is used to build instances of pmemkv Database class.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      long countAbove​(K key)
      Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are greater than the given key.
      long countAll()
      Returns number of currently stored key/value pairs in the pmemkv datastore.
      long countBelow​(K key)
      Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are less than the given key.
      long countBetween​(K key1, K key2)
      Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.
      boolean exists​(K key)
      Verifies the presence of an element with a given key in the pmemkv datastore.
      void get​(K key, ValueCallback<V> callback)
      Executes a callback function on the value for a given key
      void getAbove​(K key, KeyValueCallback<K,​V> callback)
      Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are greater than the given key.
      void getAll​(KeyValueCallback<K,​V> callback)
      Executes callback function for every key/value pair stored in the pmemkv datastore.
      void getBelow​(K key, KeyValueCallback<K,​V> callback)
      Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are less than the given key.
      void getBetween​(K key1, K key2, KeyValueCallback<K,​V> callback)
      Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.
      V getCopy​(K key)
      Gets copy of value of a given key.
      void getKeys​(KeyCallback<K> callback)
      Executes callback function for every key stored in the pmemkv datastore.
      void getKeysAbove​(K key, KeyCallback<K> callback)
      Executes callback function for every key stored in the pmemkv datastore, whose keys are greater than the given key.
      void getKeysBelow​(K key, KeyCallback<K> callback)
      Executes callback function for every key stored in the pmemkv datastore, whose keys are less than the given key.
      void getKeysBetween​(K key1, K key2, KeyCallback<K> callback)
      Executes callback function for every key stored in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.
      void put​(K key, V value)
      Inserts the key/value pair into the pmemkv datastore.
      boolean remove​(K key)
      Removes key/value pair from the pmemkv datastore for given key.
      void stop()
      Stops the running engine.
      boolean stopped()
      Checks if engine is stopped

    • Method Detail

      • stop

        public void stop()
        Stops the running engine.
        Since:
        1.0

      • stopped

        public boolean stopped()
        Checks if engine is stopped
        Returns:
        true if engine is stopped, false if it is running.
        Since:
        1.0

      • getKeys

        public void getKeys​(KeyCallback<K> callback)
        Executes callback function for every key stored in the pmemkv datastore.
        Parameters:
        callback - Function to be called for each key.
        Since:
        1.0

      • getKeysAbove

        public void getKeysAbove​(K key,
                         KeyCallback<K> callback)
        Executes callback function for every key stored in the pmemkv datastore, whose keys are greater than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the lower bound for querying.
        callback - Function to be called for each key.
        Since:
        1.0

      • getKeysBelow

        public void getKeysBelow​(K key,
                         KeyCallback<K> callback)
        Executes callback function for every key stored in the pmemkv datastore, whose keys are less than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the upper bound for querying.
        callback - Function to be called for each key.
        Since:
        1.0

      • getKeysBetween

        public void getKeysBetween​(K key1,
                           K key2,
                           KeyCallback<K> callback)
        Executes callback function for every key stored in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key1 - Sets the lower bound for querying.
        key2 - Sets the upper bound for querying.
        callback - Function to be called for each key.
        Since:
        1.0

      • countAll

        public long countAll()
        Returns number of currently stored key/value pairs in the pmemkv datastore.
        Returns:
        Total number of elements in the datastore.
        Since:
        1.0

      • countAbove

        public long countAbove​(K key)
        Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are greater than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the lower bound for querying.
        Returns:
        Number of key/value pairs in the datastore, whose keys are greater than the given key.
        Since:
        1.0

      • countBelow

        public long countBelow​(K key)
        Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are less than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the upper bound for querying.
        Returns:
        Number of key/value pairs in the datastore, whose keys are less than the given key.
        Since:
        1.0

      • countBetween

        public long countBetween​(K key1,
                         K key2)
        Returns number of currently stored key/value pairs in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key1 - Sets the lower bound for querying.
        key2 - Sets the upper bound for querying.
        Returns:
        Number of key/value pairs in the datastore, between given keys.
        Since:
        1.0

      • getAll

        public void getAll​(KeyValueCallback<K,​V> callback)
        Executes callback function for every key/value pair stored in the pmemkv datastore.
        Parameters:
        callback - Function to be called for each key/value pair.
        Since:
        1.0

      • getAbove

        public void getAbove​(K key,
                     KeyValueCallback<K,​V> callback)
        Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are greater than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the lower bound for querying.
        callback - Function to be called for each specified key/value pair.

      • getBelow

        public void getBelow​(K key,
                     KeyValueCallback<K,​V> callback)
        Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are less than the given key.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key - Sets the upper bound for querying.
        callback - Function to be called for each specified key/value pair.

      • getBetween

        public void getBetween​(K key1,
                       K key2,
                       KeyValueCallback<K,​V> callback)
        Executes callback function for every key/value pair stored in the pmemkv datastore, whose keys are greater than the key1 and less than the key2.

        Comparison mechanism is based on binary comparison of bytes - by a function equivalent to std::string::compare in C++

        Parameters:
        key1 - Sets the lower bound for querying.
        key2 - Sets the upper bound for querying.
        callback - Function to be called for each specified key/value pair.

      • exists

        public boolean exists​(K key)
        Verifies the presence of an element with a given key in the pmemkv datastore.
        Parameters:
        key - to query for.
        Returns:
        true if key exists in the datastore, false otherwise

      • get

        public void get​(K key,
                ValueCallback<V> callback)
        Executes a callback function on the value for a given key
        Parameters:
        key - key to query for.
        callback - Function to be called for each specified key/value pair.

      • getCopy

        public V getCopy​(K key)
        Gets copy of value of a given key.
        Parameters:
        key - key to query for.
        Returns:
        Copy of value associated with the given key or null if not found

      • put

        public void put​(K key,
                V value)
        Inserts the key/value pair into the pmemkv datastore.
        Parameters:
        key - the key
        value - data to be inserted for specified key

      • remove

        public boolean remove​(K key)
        Removes key/value pair from the pmemkv datastore for given key.
        Parameters:
        key - key to query for, to be removed.
        Returns:
        true if element was removed, false if element didn't exist before removal.