Package org.h2.mvstore.tx

Class TransactionMap<K,V>

java.lang.Object
java.util.AbstractMap<K,V>
org.h2.mvstore.tx.TransactionMap<K,V>
Type Parameters:
K - the key type
V - the value type
All Implemented Interfaces:
Map<K,V>
public final class TransactionMap<K,V> extends AbstractMap<K,V>
A map that supports transactions.

Methods of this class may be changed at any time without notice. If you use this class directly make sure that your application or library requires exactly the same version of MVStore or H2 jar as the version that you use during its development and build.

  • Field Details

    • map

      public final MVMap<K,VersionedValue<V>> map
      The map used for writing (the latest version).

      Key: key the key of the data. Value: { transactionId, oldVersion, value }

  • Method Details

    • getInstance

      public TransactionMap<K,V> getInstance(Transaction transaction)
      Get a clone of this map for the given transaction.
      Parameters:
      transaction - the transaction
      Returns:
      the map

    • size

      public int size()
      Get the number of entries, as a integer. Integer.MAX_VALUE is returned if there are more than this entries.
      Specified by:
      size in interface Map<K,V>
      Overrides:
      size in class AbstractMap<K,V>
      Returns:
      the number of entries, as an integer
      See Also:

    • sizeAsLongMax

      public long sizeAsLongMax()
      Get the size of the raw map. This includes uncommitted entries, and transiently removed entries, so it is the maximum number of entries.
      Returns:
      the maximum size

    • sizeAsLong

      public long sizeAsLong()
      Get the size of the map as seen by this transaction.
      Returns:
      the size

    • remove

      public V remove(Object key)
      Remove an entry.

      If the row is locked, this method will retry until the row could be updated or until a lock timeout.

      Specified by:
      remove in interface Map<K,V>
      Overrides:
      remove in class AbstractMap<K,V>
      Parameters:
      key - the key
      Throws:
      MVStoreException - if a lock timeout occurs
      ClassCastException - if type of the specified key is not compatible with this map

    • put

      public V put(K key, V value)
      Update the value for the given key.

      If the row is locked, this method will retry until the row could be updated or until a lock timeout.

      Specified by:
      put in interface Map<K,V>
      Overrides:
      put in class AbstractMap<K,V>
      Parameters:
      key - the key
      value - the new value (not null)
      Returns:
      the old value
      Throws:
      MVStoreException - if a lock timeout occurs

    • putIfAbsent

      public V putIfAbsent(K key, V value)
      Put the value for the given key if entry for this key does not exist. It is atomic equivalent of the following expression: contains(key) ? get(k) : put(key, value);
      Parameters:
      key - the key
      value - the new value (not null)
      Returns:
      the old value

    • append

      public void append(K key, V value)
      Appends entry to underlying map. This method may be used concurrently, but latest appended values are not guaranteed to be visible.
      Parameters:
      key - should be higher in map's order than any existing key
      value - to be appended

    • lock

      public V lock(K key)
      Lock row for the given key.

      If the row is locked, this method will retry until the row could be updated or until a lock timeout.

      Parameters:
      key - the key
      Returns:
      the locked value
      Throws:
      MVStoreException - if a lock timeout occurs

    • lock

      public V lock(K key, int timeoutMillis)
      Lock row for the given key.

      If the row is locked, this method will retry until the row could be updated or until a lock timeout.

      Parameters:
      key - the key
      timeoutMillis - timeout in milliseconds, -1 for default, -2 to skip locking if row is already locked by another transaction
      Returns:
      the locked value
      Throws:
      MVStoreException - if a lock timeout occurs

    • putCommitted

      public V putCommitted(K key, V value)
      Update the value for the given key, without adding an undo log entry.
      Parameters:
      key - the key
      value - the value
      Returns:
      the old value

    • tryRemove

      public boolean tryRemove(K key)
      Try to remove the value for the given key.

      This will fail if the row is locked by another transaction (that means, if another open transaction changed the row).

      Parameters:
      key - the key
      Returns:
      whether the entry could be removed

    • tryPut

      public boolean tryPut(K key, V value)
      Try to update the value for the given key.

      This will fail if the row is locked by another transaction (that means, if another open transaction changed the row).

      Parameters:
      key - the key
      value - the new value
      Returns:
      whether the entry could be updated

    • trySet

      public boolean trySet(K key, V value)
      Try to set or remove the value. When updating only unchanged entries, then the value is only changed if it was not changed after opening the map.
      Parameters:
      key - the key
      value - the new value (null to remove the value)
      Returns:
      true if the value was set, false if there was a concurrent update

    • get

      public V get(Object key)
      Get the effective value for the given key.
      Specified by:
      get in interface Map<K,V>
      Overrides:
      get in class AbstractMap<K,V>
      Parameters:
      key - the key
      Returns:
      the value or null
      Throws:
      ClassCastException - if type of the specified key is not compatible with this map

    • getFromSnapshot

      public V getFromSnapshot(K key)
      Get the value for the given key, or null if value does not exist in accordance with transactional rules. Value is taken from a snapshot, appropriate for an isolation level of the related transaction
      Parameters:
      key - the key
      Returns:
      the value, or null if not found

    • getImmediate

      public V getImmediate(K key)
      Get the value for the given key, or null if not found. Operation is performed on a snapshot of the map taken during this call.
      Parameters:
      key - the key
      Returns:
      the value, or null if not found

    • containsKey

      public boolean containsKey(Object key)
      Whether the map contains the key.
      Specified by:
      containsKey in interface Map<K,V>
      Overrides:
      containsKey in class AbstractMap<K,V>
      Parameters:
      key - the key
      Returns:
      true if the map contains an entry for this key
      Throws:
      ClassCastException - if type of the specified key is not compatible with this map

    • isDeletedByCurrentTransaction

      public boolean isDeletedByCurrentTransaction(K key)
      Check if the row was deleted by this transaction.
      Parameters:
      key - the key
      Returns:
      true if it was

    • isSameTransaction

      public boolean isSameTransaction(K key)
      Whether the entry for this key was added or removed from this session.
      Parameters:
      key - the key
      Returns:
      true if yes

    • isClosed

      public boolean isClosed()
      Check whether this map is closed.
      Returns:
      true if closed

    • clear

      public void clear()
      Clear the map.
      Specified by:
      clear in interface Map<K,V>
      Overrides:
      clear in class AbstractMap<K,V>

    • entrySet

      public Set<Map.Entry<K,V>> entrySet()
      Specified by:
      entrySet in interface Map<K,V>
      Specified by:
      entrySet in class AbstractMap<K,V>

    • firstEntry

      public Map.Entry<K,V> firstEntry()
      Get the first entry.
      Returns:
      the first entry, or null if empty

    • firstKey

      public K firstKey()
      Get the first key.
      Returns:
      the first key, or null if empty

    • lastEntry

      public Map.Entry<K,V> lastEntry()
      Get the last entry.
      Returns:
      the last entry, or null if empty

    • lastKey

      public K lastKey()
      Get the last key.
      Returns:
      the last key, or null if empty

    • higherEntry

      public Map.Entry<K,V> higherEntry(K key)
      Get the entry with smallest key that is larger than the given key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • higherKey

      public K higherKey(K key)
      Get the smallest key that is larger than the given key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • ceilingEntry

      public Map.Entry<K,V> ceilingEntry(K key)
      Get the entry with smallest key that is larger than or equal to this key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • ceilingKey

      public K ceilingKey(K key)
      Get the smallest key that is larger than or equal to this key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • floorEntry

      public Map.Entry<K,V> floorEntry(K key)
      Get the entry with largest key that is smaller than or equal to this key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • floorKey

      public K floorKey(K key)
      Get the largest key that is smaller than or equal to this key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • lowerEntry

      public Map.Entry<K,V> lowerEntry(K key)
      Get the entry with largest key that is smaller than the given key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • lowerKey

      public K lowerKey(K key)
      Get the largest key that is smaller than the given key, or null if no such key exists.
      Parameters:
      key - the key (may not be null)
      Returns:
      the result

    • keyIterator

      public Iterator<K> keyIterator(K from)
      Iterate over keys.
      Parameters:
      from - the first key to return
      Returns:
      the iterator

    • keyIterator

      public TransactionMap.TMIterator<K,V,K> keyIterator(K from, boolean reverse)
      Iterate over keys in the specified order.
      Parameters:
      from - the first key to return
      reverse - if true, iterate in reverse (descending) order
      Returns:
      the iterator

    • keyIterator

      public TransactionMap.TMIterator<K,V,K> keyIterator(K from, K to)
      Iterate over keys.
      Parameters:
      from - the first key to return
      to - the last key to return or null if there is no limit
      Returns:
      the iterator

    • keyIterator

      public TransactionMap.TMIterator<K,V,K> keyIterator(K from, K to, boolean reverse)
      Iterate over keys.
      Parameters:
      from - the first key to return
      to - the last key to return or null if there is no limit
      reverse - if true, iterate in reverse (descending) order
      Returns:
      the iterator

    • keyIteratorUncommitted

      public TransactionMap.TMIterator<K,V,K> keyIteratorUncommitted(K from, K to)
      Iterate over keys, including keys from uncommitted entries.
      Parameters:
      from - the first key to return
      to - the last key to return or null if there is no limit
      Returns:
      the iterator

    • entryIterator

      public TransactionMap.TMIterator<K,V,Map.Entry<K,V>> entryIterator(K from, K to)
      Iterate over entries.
      Parameters:
      from - the first key to return
      to - the last key to return
      Returns:
      the iterator

    • entryIterator

      public TransactionMap.TMIterator<K,V,Map.Entry<K,V>> entryIterator(K from, K to, boolean reverse)
      Iterate over entries.
      Parameters:
      from - the first key to return
      to - the last key to return
      reverse - if true, iterate in reverse (descending) order
      Returns:
      the iterator

    • getTransaction

      public Transaction getTransaction()

    • getKeyType

      public DataType<K> getKeyType()