redis.clients.jedis.commands

Interface SetCommands

All Known Subinterfaces:

JedisCommands

All Known Implementing Classes:

Jedis, JedisCluster, JedisPooled, JedisSharding, UnifiedJedis

public interface SetCommands

Method Summary

Modifier and Type	Method and Description
long	sadd(String key, String... members) Add the specified member to the set value stored at key.
long	scard(String key) Return the set cardinality (number of elements).
Set<String>	sdiff(String... keys) Return the difference between the Sets stored at keys
long	sdiffstore(String dstkey, String... keys) This command works exactly like SDIFF but instead of being returned the resulting set is stored in dstkey.
Set<String>	sinter(String... keys) Return the members of a set resulting from the intersection of all the sets hold at the specified keys.
long	sintercard(int limit, String... keys) This command works exactly like SINTER but instead of returning the result set, it returns just the cardinality of the result.
long	sintercard(String... keys) This command works exactly like SINTER but instead of returning the result set, it returns just the cardinality of the result.
long	sinterstore(String dstkey, String... keys) This command works exactly like SINTER but instead of being returned the resulting set is stored as dstkey.
boolean	sismember(String key, String member) Return true if member is a member of the set stored at key, otherwise false is returned.
Set<String>	smembers(String key) Return all the members (elements) of the set value stored at key.
List<Boolean>	smismember(String key, String... members) Returns whether each member is a member of the set stored at key.
long	smove(String srckey, String dstkey, String member) Move the specified member from the set at srckey to the set at dstkey.
String	spop(String key) Remove a random element from a Set returning it as return value.
Set<String>	spop(String key, long count) By default, the command spop(String) pops a single member from the set.
String	srandmember(String key) Return a random element from a Set, without removing the element.
List<String>	srandmember(String key, int count) Return a random elements from a Set, without removing the elements.
long	srem(String key, String... members) Remove the specified member from the set value stored at key.
default ScanResult<String>	sscan(String key, String cursor)
ScanResult<String>	sscan(String key, String cursor, ScanParams params)
Set<String>	sunion(String... keys) Return the members of a set resulting from the union of all the sets hold at the specified keys.
long	sunionstore(String dstkey, String... keys) This command works exactly like SUNION but instead of being returned the resulting set is stored as dstkey.

Method Detail

sadd

long sadd(String key,
          String... members)

Add the specified member to the set value stored at key. If member is already a member of the set no operation is performed. If key does not exist a new set with the specified member as sole member is created. If the key exists but does not hold a set value an error is returned.

Time complexity O(1)

Parameters:

key -

members -

Returns:

The number of elements that were added to the set, not including all the elements already present in the set

smembers

Set<String> smembers(String key)

Return all the members (elements) of the set value stored at key. This is just syntax glue for SINTER.

Time complexity O(N)

Parameters:

key -

Returns:

All elements of the set

srem

long srem(String key,
          String... members)

Remove the specified member from the set value stored at key. If member was not a member of the set no operation is performed. If key does not hold a set value an error is returned.

Time complexity O(1)

Parameters:

key -

members -

Returns:

The number of members that were removed from the set, not including non-existing members

spop

String spop(String key)

Remove a random element from a Set returning it as return value. If the Set is empty or the key does not exist, a nil object is returned.

The srandmember(String) command does a similar work but the returned element is not removed from the Set.

Time complexity O(1)

Parameters:

key -

Returns:

The removed member, or nil when key does not exist

spop

Set<String> spop(String key,
                 long count)

By default, the command spop(String) pops a single member from the set. In this command, the reply will consist of up to count members, depending on the set's cardinality.

The srandmember(String) command does a similar work but the returned element is not removed from the Set.

Time complexity O(N), where N is the value of the passed count

Parameters:

key -

count -

Returns:

The removed members

scard

long scard(String key)

Return the set cardinality (number of elements). If the key does not exist 0 is returned, like for empty sets.

Parameters:

key -

Returns:

The cardinality (number of elements) of the set

sismember

boolean sismember(String key,
                  String member)

Return true if member is a member of the set stored at key, otherwise false is returned.

Time complexity O(1)

Parameters:

key -

member -

Returns:

true if the element is a member of the set, false otherwise

smismember

List<Boolean> smismember(String key,
                         String... members)

Returns whether each member is a member of the set stored at key.

Time complexity O(N) where N is the number of elements being checked for membership

Parameters:

key -

members -

Returns:

List representing the membership of the given elements, in the same order as they are requested

srandmember

String srandmember(String key)

Return a random element from a Set, without removing the element. If the Set is empty or the key does not exist, a nil object is returned.

The SPOP command does a similar work but the returned element is popped (removed) from the Set.

Time complexity O(1)

Parameters:

key -

Returns:

The randomly selected element

srandmember

List<String> srandmember(String key,
                         int count)

Return a random elements from a Set, without removing the elements. If the Set is empty or the key does not exist, an empty list is returned.

The SPOP command does a similar work but the returned element is popped (removed) from the Set.

Time complexity O(1)

Parameters:

key -

count - if positive, return an array of distinct elements. If negative the behavior changes and the command is allowed to return the same element multiple times

Returns:

A list of randomly selected elements

sscan

default ScanResult<String> sscan(String key,
                                 String cursor)

sscan

ScanResult<String> sscan(String key,
                         String cursor,
                         ScanParams params)

sdiff

Set<String> sdiff(String... keys)

Return the difference between the Sets stored at keys

Example:

 key1 = [x, a, b, c]
 key2 = [c]
 key3 = [a, d]
 SDIFF key1,key2,key3 => [x, b]
 

Non existing keys are considered like empty sets.

Time complexity O(N) with N being the total number of elements of all the sets

Parameters:

keys - group of sets

Returns:

The members of a set resulting from the difference between the sets

sdiffstore

long sdiffstore(String dstkey,
                String... keys)

This command works exactly like SDIFF but instead of being returned the resulting set is stored in dstkey.

Parameters:

dstkey -

keys - group of sets

Returns:

The number of elements in the resulting set

sinter

Set<String> sinter(String... keys)

Return the members of a set resulting from the intersection of all the sets hold at the specified keys. Like in LRANGE the result is sent to the connection as a multi-bulk reply (see the protocol specification for more information). If just a single key is specified, then this command produces the same result as SMEMBERS. Actually SMEMBERS is just syntax sugar for SINTER.

Non existing keys are considered like empty sets, so if one of the keys is missing an empty set is returned (since the intersection with an empty set always is an empty set).

Time complexity O(N*M) worst case where N is the cardinality of the smallest set and M the number of sets

Parameters:

keys - group of sets

Returns:

A set with members of the resulting set

sinterstore

long sinterstore(String dstkey,
                 String... keys)

This command works exactly like SINTER but instead of being returned the resulting set is stored as dstkey.

Time complexity O(N*M) worst case where N is the cardinality of the smallest set and M the number of sets

Parameters:

dstkey -

keys - group of sets

Returns:

The number of elements in the resulting set

sintercard

long sintercard(String... keys)

This command works exactly like SINTER but instead of returning the result set, it returns just the cardinality of the result. LIMIT defaults to 0 and means unlimited

Time complexity O(N*M) worst case where N is the cardinality of the smallest

Parameters:

keys - group of sets

Returns:

The cardinality of the set which would result from the intersection of all the given sets

sintercard

long sintercard(int limit,
                String... keys)

This command works exactly like SINTER but instead of returning the result set, it returns just the cardinality of the result.

Time complexity O(N*M) worst case where N is the cardinality of the smallest

Parameters:

limit - If the intersection cardinality reaches limit partway through the computation, the algorithm will exit and yield limit as the cardinality.

keys - group of sets

Returns:

The cardinality of the set which would result from the intersection of all the given sets

sunion

Set<String> sunion(String... keys)

Return the members of a set resulting from the union of all the sets hold at the specified keys. Like in LRANGE the result is sent to the connection as a multi-bulk reply (see the protocol specification for more information). If just a single key is specified, then this command produces the same result as SMEMBERS.

Non existing keys are considered like empty sets.

Time complexity O(N) where N is the total number of elements in all the provided sets

Parameters:

keys - group of sets

Returns:

A set with members of the resulting set

sunionstore

long sunionstore(String dstkey,
                 String... keys)

This command works exactly like SUNION but instead of being returned the resulting set is stored as dstkey. Any existing value in dstkey will be over-written.

Time complexity O(N) where N is the total number of elements in all the provided sets

Parameters:

dstkey -

keys - group of sets

Returns:

The number of elements in the resulting set

smove

long smove(String srckey,
           String dstkey,
           String member)

Move the specified member from the set at srckey to the set at dstkey. This operation is atomic, in every given moment the element will appear to be in the source or destination set for accessing clients.

If the source set does not exist or does not contain the specified element no operation is performed and zero is returned, otherwise the element is removed from the source set and added to the destination set. On success one is returned, even if the element was already present in the destination set.

An error is raised if the source or destination keys contain a non Set value.

Time complexity O(1)

Parameters:

srckey -

dstkey -

member -

Returns:

1 if the element was moved, 0 if no operation was performed