Package io.permazen.kv.spanner

Class ReadOnlySpannerView

java.lang.Object
io.permazen.kv.AbstractKVStore
io.permazen.kv.spanner.ReadOnlySpannerView
All Implemented Interfaces:
CloseableKVStore, KVStore, Closeable, AutoCloseable
public class ReadOnlySpannerView extends AbstractKVStore implements CloseableKVStore
Provides a (read-only) KVStore view of a ReadContext.

For best performance, consider wrapping an instance of this class in a CachingKVStore.

See Also:

  • Field Details

    • log

      protected final Logger log

    • tableName

      protected final String tableName

    • context

      protected final com.google.cloud.spanner.ReadContext context

    • exceptionMapper

      protected final Function<? super com.google.cloud.spanner.SpannerException,RuntimeException> exceptionMapper

  • Constructor Details

    • ReadOnlySpannerView

      public ReadOnlySpannerView(String tableName, com.google.cloud.spanner.ReadContext context, Function<? super com.google.cloud.spanner.SpannerException,RuntimeException> exceptionMapper)
      Primary constructor.
      Parameters:
      tableName - name of the Spanner database table
      context - read context
      exceptionMapper - mapper for any thrown SpannerExceptions, or null for none
      Throws:
      IllegalArgumentException - if tableName or context is null

    • ReadOnlySpannerView

      public ReadOnlySpannerView(String tableName, com.google.cloud.spanner.ReadContext context)
      Convenience constructor.

      Equivalent to ReadOnlySpannerView(tableName, context, null).

      Parameters:
      tableName - name of the Spanner database table
      context - read context
      Throws:
      IllegalArgumentException - if tableName or context is null

  • Method Details

    • get

      public byte[] get(byte[] key)
      Description copied from interface: KVStore
      Get the value associated with the given key, if any.

      Modifications to the returned byte[] array do not affect this instance.

      Specified by:
      get in interface KVStore
      Overrides:
      get in class AbstractKVStore
      Parameters:
      key - key
      Returns:
      value associated with key, or null if not found

    • getAtLeast

      public KVPair getAtLeast(byte[] minKey, byte[] maxKey)
      Description copied from interface: KVStore
      Get the key/value pair having the smallest key greater than or equal to the given minimum, if any.

      An optional (exclusive) maximum key may also be specified; if maxKey is null, there is no upper bound; if maxKey <= minKey, null is always returned.

      If keys starting with 0xff are not supported by this instance, and minKey starts with 0xff, then this method returns null.

      Modifications to the returned byte[] arrays do not affect this instance.

      Specified by:
      getAtLeast in interface KVStore
      Overrides:
      getAtLeast in class AbstractKVStore
      Parameters:
      minKey - minimum key (inclusive), or null for no minimum (get the smallest key)
      maxKey - maximum key (exclusive), or null for no maximum (no upper bound)
      Returns:
      smallest key/value pair with key >= minKey and key < maxKey, or null if none exists

    • getAtMost

      public KVPair getAtMost(byte[] maxKey, byte[] minKey)
      Description copied from interface: KVStore
      Get the key/value pair having the largest key strictly less than the given maximum, if any.

      An optional (inclusive) minimum key may also be specified; if minKey is null, there is no lower bound (equivalent to a lower bound of the empty byte array); if minKey >= maxKey, null is always returned.

      If keys starting with 0xff are not supported by this instance, and maxKey starts with 0xff, then this method behaves as if maxKey were null.

      Modifications to the returned byte[] arrays do not affect this instance.

      Specified by:
      getAtMost in interface KVStore
      Overrides:
      getAtMost in class AbstractKVStore
      Parameters:
      maxKey - maximum key (exclusive), or null for no maximum (get the largest key)
      minKey - minimum key (inclusive), or null for no minimum (no lower bound)
      Returns:
      largest key/value pair with key < maxKey and key >= minKey, or null if none exists

    • getRange

      public CloseableIterator<KVPair> getRange(byte[] minKey, byte[] maxKey, boolean reverse)
      Description copied from interface: KVStore
      Iterate the key/value pairs in the specified range. The returned CloseableIterator's remove() method must be supported and should have the same effect as invoking remove() on the corresponding key.

      If keys starting with 0xff are not supported by this instance, and minKey starts with 0xff, then this method returns an empty iteration.

      If keys starting with 0xff are not supported by this instance, and maxKey starts with 0xff, then this method behaves as if maxKey were null.

      The returned CloseableIterator is weakly consistent (see java.util.concurrent). In short, the returned CloseableIterator must not throw ConcurrentModificationException; however, whether or not a "live" CloseableIterator reflects any modifications made after its creation is implementation dependent. Implementations that do make post-creation updates visible in the CloseableIterator, even if the update occurs after some delay, must preserve the order in which the modifications actually occurred.

      The returned CloseableIterator itself is not guaranteed to be thread safe; is should only be used in the thread that created it.

      Invokers of this method are encouraged to close() the returned iterators, though this is not required for correct behavior.

      Modifications to the returned KVPair key and value byte[] arrays do not affect this instance.

      Specified by:
      getRange in interface KVStore
      Parameters:
      minKey - minimum key (inclusive), or null for no minimum (start at the smallest key)
      maxKey - maximum key (exclusive), or null for no maximum (end at the largest key)
      reverse - true to return key/value pairs in reverse order (i.e., keys descending)
      Returns:
      iteration of key/value pairs in the range minKey (inclusive) to maxKey (exclusive)

    • put

      public void put(byte[] key, byte[] value)
      Description copied from interface: KVStore
      Set the value associated with the given key.
      Specified by:
      put in interface KVStore
      Overrides:
      put in class AbstractKVStore
      Parameters:
      key - key
      value - value

    • remove

      public void remove(byte[] key)
      Description copied from interface: KVStore
      Remove the key/value pair with the given key, if it exists.
      Specified by:
      remove in interface KVStore
      Overrides:
      remove in class AbstractKVStore
      Parameters:
      key - key

    • removeRange

      public void removeRange(byte[] minKey, byte[] maxKey)
      Description copied from interface: KVStore
      Remove all key/value pairs whose keys are in a given range.

      The minKey must be less than or equal to maxKey; if they equal (and not null) then nothing happens; if they are both null then all entries are deleted.

      If keys starting with 0xff are not supported by this instance, then:

      • If minKey starts with 0xff, then no change occurs
      • If maxKey starts with 0xff, then this method behaves as if maxKey were null
      Specified by:
      removeRange in interface KVStore
      Overrides:
      removeRange in class AbstractKVStore
      Parameters:
      minKey - minimum key (inclusive), or null for no minimum
      maxKey - maximum key (exclusive), or null for no maximum

    • close

      public void close()
      Closes the associated ReadContext.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface CloseableKVStore

    • kv

      protected static KVPair kv(com.google.cloud.spanner.Struct struct)