Package de.xima.fc.common.collection

Interface CrudMapAdapter<Key,Value>

Type Parameters:

Key - Type of the keys

Value - Type of the values associated with the keys.

All Known Implementing Classes:

CrudMapAdapter.Immutable, CrudMapAdapter.SetLike, CrudMapAdapter.SetLike.Immutable, TextFileSystemViewCrudMapAdapter

public interface CrudMapAdapter<Key,Value>

CRUD = create, read, update, and delete

A data adapter with operations for adding, reading, updating, and deleting values indexed by a key.

Since:

8.2.0

Author:

XIMA MEDIA GmbH

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	CrudMapAdapter.Immutable<Key,Value>	A CrudMapAdapter for an immutable map.
static class	CrudMapAdapter.SetLike<Value>	A CrudMapAdapter with a Unit whose presence corresponds to whether the key is present in a Set.

Method Summary

Modifier and Type	Method	Description
default int	computeSize()	Gets the number of values associated with a key.
void	delete(Key key)	Removes the mapping for the given key.
Iterable<Key>	enumerateCandidateKeys()	Enumerates all keys for which a mapping may be present.
Value	get(Key key)	Gets the value for the given key.
default boolean	isEmpty()	Checks whether any keys are associated with a value.
void	set(Key key, Value value)	Associates a value with the given key.

Method Detail

computeSize

default int computeSize()

Gets the number of values associated with a key.

The default implementation iterates through each candidate key and checks which keys are associated with a value.

Returns:

The number of existing key-value pairs.

delete

void delete(Key key)

Removes the mapping for the given key.

Parameters:

key - Key to disassociate with any values.

enumerateCandidateKeys

Iterable<Key> enumerateCandidateKeys()

Enumerates all keys for which a mapping may be present. May include additional keys for which no value is available, see computeSize(). Must NOT contain duplicate keys.

Returns:

A set with all potential keys.

get

Value get(Key key)

Gets the value for the given key. Returns null when no value is available for the key.

Parameters:

key - Key to access.

Returns:

The value associated with the key, or null when no value is associated with the key.

isEmpty

default boolean isEmpty()

Checks whether any keys are associated with a value.

The default implementation iterates through each candidate key and checks if any key is associated with a value.

Returns:

true if no keys are associated with a value.

set

void set(Key key,
         Value value)

Associates a value with the given key.

Parameters:

key - Key to associate with a different value.

value - Value to associate with the key, never null.