redis.clients.jedis.commands

Interface StringCommands

All Superinterfaces:

BitCommands

All Known Subinterfaces:

JedisCommands

All Known Implementing Classes:

Jedis, JedisCluster, JedisPooled, JedisSentineled, JedisSharding, UnifiedJedis

public interface StringCommands
extends BitCommands

Method Summary

Modifier and Type	Method and Description
long	append(java.lang.String key, java.lang.String value) Append Command If the key already exists and is a string, this command appends the provided value at the end of the string.
long	decr(java.lang.String key) Decr Command Decrement the number stored at key by one.
long	decrBy(java.lang.String key, long decrement) DecrBy Command DECRBY work just like DECR but instead to decrement by 1 the decrement is integer.
java.lang.String	get(java.lang.String key) Get Command Get the value of the specified key.
java.lang.String	getDel(java.lang.String key) GetDel Command Get the value of key and delete the key.
java.lang.String	getEx(java.lang.String key, GetExParams params) GetEx Command Get the value of key and optionally set its expiration.
java.lang.String	getrange(java.lang.String key, long startOffset, long endOffset) GetRange Command Return the substring of the string value stored at key, determined by the offsets start and end (both are inclusive).
java.lang.String	getSet(java.lang.String key, java.lang.String value) GetSet Command GETSET is an atomic set this value and return the old value command.
long	incr(java.lang.String key) Incr Command Increment the number stored at key by one.
long	incrBy(java.lang.String key, long increment) IncrBy Command INCRBY work just like INCR but instead to increment by 1 the increment is integer.
double	incrByFloat(java.lang.String key, double increment) IncrByFloat Command INCRBYFLOAT work just like incrBy(String, long) INCRBY} but increments by floats instead of integers.
LCSMatchResult	lcs(java.lang.String keyA, java.lang.String keyB, LCSParams params) Calculate the longest common subsequence of keyA and keyB.
java.util.List<java.lang.String>	mget(java.lang.String... keys) MGet Command Get the values of all the specified keys.
java.lang.String	mset(java.lang.String... keysvalues) MSet Command Set the the respective keys to the respective values.
long	msetnx(java.lang.String... keysvalues) MSetNX Command Set the respective keys to the respective values.
java.lang.String	psetex(java.lang.String key, long milliseconds, java.lang.String value) PSetEx Command PSETEX works exactly like SETEX with the sole difference that the expire time is specified in milliseconds instead of seconds.
java.lang.String	set(java.lang.String key, java.lang.String value) Set Command Set the string value as value of the key.
java.lang.String	set(java.lang.String key, java.lang.String value, SetParams params) Set Command Set the string value as value of the key.
java.lang.String	setex(java.lang.String key, long seconds, java.lang.String value) SetEx Command The command is exactly equivalent to the following group of commands: SET + EXPIRE.
java.lang.String	setGet(java.lang.String key, java.lang.String value)
java.lang.String	setGet(java.lang.String key, java.lang.String value, SetParams params)
long	setnx(java.lang.String key, java.lang.String value) SetNE Command SETNX works exactly like SET with the only difference that if the key already exists no operation is performed.
long	setrange(java.lang.String key, long offset, java.lang.String value) SetRange Command GETRANGE overwrite part of the string stored at key, starting at the specified offset, for the entire length of value.
long	strlen(java.lang.String key) StrLen Command Return the length of the string value stored at key.
java.lang.String	substr(java.lang.String key, int start, int end) SubStr Command Return a subset of the string from offset start to offset end (both offsets are inclusive).

Methods inherited from interface redis.clients.jedis.commands.BitCommands

bitcount, bitcount, bitcount, bitfield, bitfieldReadonly, bitop, bitpos, bitpos, getbit, setbit

Method Detail

set

java.lang.String set(java.lang.String key,
                     java.lang.String value)

Set Command Set the string value as value of the key. The string can't be longer than 1073741824 bytes (1 GB).

Time complexity: O(1)

Parameters:

key -

value -

Returns:

OK

set

java.lang.String set(java.lang.String key,
                     java.lang.String value,
                     SetParams params)

Set Command Set the string value as value of the key. Can be used with optional params.

Time complexity: O(1)

Parameters:

key -

value -

params - SetParams

Returns:

simple-string-reply OK if SET was executed correctly, or null if the SET operation was not performed because the user specified the NX or XX option but the condition was not met.

get

java.lang.String get(java.lang.String key)

Get Command Get the value of the specified key. If the key does not exist the special value 'nil' is returned. If the value stored at key is not a string an error is returned because GET can only handle string values.

Time complexity: O(1)

Parameters:

key -

Returns:

The value stored in key

setGet

java.lang.String setGet(java.lang.String key,
                        java.lang.String value)

setGet

java.lang.String setGet(java.lang.String key,
                        java.lang.String value,
                        SetParams params)

getDel

java.lang.String getDel(java.lang.String key)

GetDel Command Get the value of key and delete the key. This command is similar to GET, except for the fact that it also deletes the key on success (if and only if the key's value type is a string).

Time complexity: O(1)

Parameters:

key -

Returns:

The value stored in key

getEx

java.lang.String getEx(java.lang.String key,
                       GetExParams params)

GetEx Command Get the value of key and optionally set its expiration. GETEX is similar to GET, but is a write command with additional options: EX seconds -- Set the specified expire time, in seconds. PX milliseconds -- Set the specified expire time, in milliseconds. EXAT timestamp-seconds -- Set the specified Unix time at which the key will expire, in seconds. PXAT timestamp-milliseconds -- Set the specified Unix time at which the key will expire, in milliseconds. PERSIST -- Remove the time to live associated with the key.

Time complexity: O(1)

Parameters:

key -

params - GetExParams

Returns:

The value stored in key

setrange

long setrange(java.lang.String key,
              long offset,
              java.lang.String value)

SetRange Command GETRANGE overwrite part of the string stored at key, starting at the specified offset, for the entire length of value. If the offset is larger than the current length of the string at key, the string is padded with zero-bytes to make offset fit. Non-existing keys are considered as empty strings, so this command will make sure it holds a string large enough to be able to set value at offset.

Time complexity: O(1)

Parameters:

key -

offset -

value -

Returns:

The length of the string after it was modified by the command

getrange

java.lang.String getrange(java.lang.String key,
                          long startOffset,
                          long endOffset)

GetRange Command Return the substring of the string value stored at key, determined by the offsets start and end (both are inclusive). Negative offsets can be used in order to provide an offset starting from the end of the string. So -1 means the last character, -2 the penultimate and so forth.

Time complexity: O(N) where N is the length of the returned string

Parameters:

key -

startOffset -

endOffset -

Returns:

The substring

getSet

java.lang.String getSet(java.lang.String key,
                        java.lang.String value)

GetSet Command GETSET is an atomic set this value and return the old value command. Set key to the string value and return the old value stored at key. The string can't be longer than 1073741824 byte (1 GB).

Time complexity: O(1)

Parameters:

key -

value -

Returns:

The old value that was stored in key

setnx

long setnx(java.lang.String key,
           java.lang.String value)

SetNE Command SETNX works exactly like SET with the only difference that if the key already exists no operation is performed. SETNX actually means "SET if Not Exists".

Time complexity: O(1)

Parameters:

key -

value -

Returns:

1 if the key was set, 0 otherwise

setex

java.lang.String setex(java.lang.String key,
                       long seconds,
                       java.lang.String value)

SetEx Command The command is exactly equivalent to the following group of commands: SET + EXPIRE. The operation is atomic.

Time complexity: O(1)

Parameters:

key -

seconds -

value -

Returns:

OK

psetex

java.lang.String psetex(java.lang.String key,
                        long milliseconds,
                        java.lang.String value)

PSetEx Command PSETEX works exactly like SETEX with the sole difference that the expire time is specified in milliseconds instead of seconds.

Time complexity: O(1)

Parameters:

key -

milliseconds -

value -

Returns:

OK

mget

java.util.List<java.lang.String> mget(java.lang.String... keys)

MGet Command Get the values of all the specified keys. If one or more keys don't exist or is not of type String, a 'nil' value is returned instead of the value of the specified key, but the operation never fails.

Time complexity: O(1) for every key

Parameters:

keys -

Returns:

Multi bulk reply

mset

java.lang.String mset(java.lang.String... keysvalues)

MSet Command Set the the respective keys to the respective values. MSET will replace old values with new values, while MSETNX will not perform any operation at all even if just a single key already exists.

Because of this semantic MSETNX can be used in order to set different keys representing different fields of an unique logic object in a way that ensures that either all the fields or none at all are set.

Both MSET and MSETNX are atomic operations. This means that for instance if the keys A and B are modified, another connection talking to Redis can either see the changes to both A and B at once, or no modification at all.

Parameters:

keysvalues - pairs of keys and their values e.g mset("foo", "foovalue", "bar", "barvalue")

Returns:

OK

msetnx

long msetnx(java.lang.String... keysvalues)

MSetNX Command Set the respective keys to the respective values. MSET will replace old values with new values, while MSETNX will not perform any operation at all even if just a single key already exists.

Because of this semantic MSETNX can be used in order to set different keys representing different fields of an unique logic object in a way that ensures that either all the fields or none at all are set.

Both MSET and MSETNX are atomic operations. This means that for instance if the keys A and B are modified, another connection talking to Redis can either see the changes to both A and B at once, or no modification at all.

Parameters:

keysvalues - pairs of keys and their values e.g msetnx("foo", "foovalue", "bar", "barvalue")

Returns:

1 if the all the keys were set, 0 if no key was set (at least one key already existed)

incr

long incr(java.lang.String key)

Incr Command Increment the number stored at key by one. If the key does not exist or contains a value of a wrong type, set the key to the value of "0" before to perform the increment operation.

INCR commands are limited to 64 bit signed integers.

Note: this is actually a string operation, that is, in Redis there are not "integer" types. Simply the string stored at the key is parsed as a base 10 64 bit signed integer, incremented, and then converted back as a string.

Time complexity: O(1)

Parameters:

key - the key to increment

Returns:

The value of the key after the increment

incrBy

long incrBy(java.lang.String key,
            long increment)

IncrBy Command INCRBY work just like INCR but instead to increment by 1 the increment is integer.

INCR commands are limited to 64 bit signed integers.

Note: this is actually a string operation, that is, in Redis there are not "integer" types. Simply the string stored at the key is parsed as a base 10 64 bit signed integer, incremented, and then converted back as a string.

Time complexity: O(1)

Parameters:

key - the key to increment

increment - the value to increment by

Returns:

The value of the key after the increment

incrByFloat

double incrByFloat(java.lang.String key,
                   double increment)

IncrByFloat Command INCRBYFLOAT work just like incrBy(String, long) INCRBY} but increments by floats instead of integers.

INCRBYFLOAT commands are limited to double precision floating point values.

Note: this is actually a string operation, that is, in Redis there are not "double" types. Simply the string stored at the key is parsed as a base double precision floating point value, incremented, and then converted back as a string. There is no DECRYBYFLOAT but providing a negative value will work as expected.

Time complexity: O(1)

Parameters:

key - the key to increment

increment - the value to increment by

Returns:

The value of the key after the increment

decr

long decr(java.lang.String key)

Decr Command Decrement the number stored at key by one. If the key does not exist or contains a value of a wrong type, set the key to the value of "0" before to perform the decrement operation.

DECR commands are limited to 64 bit signed integers.

Note: this is actually a string operation, that is, in Redis there are not "integer" types. Simply the string stored at the key is parsed as a base 10 64 bit signed integer, incremented, and then converted back as a string.

Time complexity: O(1)

Parameters:

key - the key to decrement

Returns:

The value of the key after the decrement

decrBy

long decrBy(java.lang.String key,
            long decrement)

DecrBy Command DECRBY work just like DECR but instead to decrement by 1 the decrement is integer.

DECRBY commands are limited to 64 bit signed integers.

Note: this is actually a string operation, that is, in Redis there are not "integer" types. Simply the string stored at the key is parsed as a base 10 64 bit signed integer, incremented, and then converted back as a string.

Time complexity: O(1)

Parameters:

key - the key to decrement

decrement - the value to decrement by

Returns:

The value of the key after the decrement

append

long append(java.lang.String key,
            java.lang.String value)

Append Command If the key already exists and is a string, this command appends the provided value at the end of the string. If the key does not exist it is created and set as an empty string, so APPEND will be very similar to SET in this special case.

Time complexity: O(1). The amortized time complexity is O(1) assuming the appended value is small and the already present value is of any size, since the dynamic string library used by Redis will double the free space available on every reallocation.

Parameters:

key - the key to append to

value - the value to append

Returns:

The total length of the string after the append operation.

substr

java.lang.String substr(java.lang.String key,
                        int start,
                        int end)

SubStr Command Return a subset of the string from offset start to offset end (both offsets are inclusive). Negative offsets can be used in order to provide an offset starting from the end of the string. So -1 means the last char, -2 the penultimate and so forth.

The function handles out of range requests without raising an error, but just limiting the resulting range to the actual length of the string.

Time complexity: O(start+n) (with start being the start index and n the total length of the requested range). Note that the lookup part of this command is O(1) so for small strings this is actually an O(1) command.

Parameters:

key -

start -

end -

Returns:

The substring

strlen

long strlen(java.lang.String key)

StrLen Command Return the length of the string value stored at key.

Parameters:

key -

Returns:

The length of the string at key, or 0 when key does not exist

lcs

LCSMatchResult lcs(java.lang.String keyA,
                   java.lang.String keyB,
                   LCSParams params)

Calculate the longest common subsequence of keyA and keyB.

Parameters:

keyA -

keyB -

params -

Returns:

According to LCSParams to decide to return content to fill LCSMatchResult.