org.jredis

Interface Sort

All Superinterfaces:

Query

All Known Subinterfaces:

SemanticSort<T>

All Known Implementing Classes:

SortSupport

public interface Sort
extends Query

Sort, a type of Query, provides for specifying and chaining the query predicates. The results of the sort directive are returned as an ordered List of byte[] values.

Sort instances are obtained directly from the JRedis client, by calling the eponymous method JRedis#sort(String), which expects a key name as its required arguments.
[Note: this provides the pattern for all future query types: required args are specified in the method that returns the Query form.]

As with all Query forms, do not forget to call Query.exec() at the end!

Usage:

 List  results = redis.sort("my-list-or-set-key").BY("weight*").LIMIT(1, 11).GET("object*").DESC().ALPHA().exec();
 for(byte[] item : results) {
     // do something with item ..
  }
 

Sort specification elements are all optional. You could simply say:

 List  results = redis.sort("my-list-or-set-key").exec();
 for(byte[] item : results) {
     // do something with item ..
  }
 

Sort specification elements are also can appear in any order -- the client implementation will send them to the server in the order expected by the protocol, although it is good form to specify the predicates in natural order:

 List  results = redis.sort("my-list-or-set-key").GET("object*").DESC().ALPHA().BY("weight*").LIMIT(1, 11).exec();
 for(byte[] item : results) {
     // do something with item ..
  }
 

Since:

alpha.0

Version:

alpha.0, 04/02/09

Author:

Joubin Houshyar (alphazero@sensesay.net)

Nested Class Summary

Nested classes/interfaces inherited from interface org.jredis.Query

Query.Support

Method Summary

Modifier and Type	Method and Description
Sort	ALPHA() sort is be default numeric -- use this to indicate lexiographic alphanumeric sort
<K> Sort	BY(K pattern) species the BY clause
Sort	DESC() default sort is ASCending -- use this in your sort to specify DESC sort
<K> Sort	GET(K pattern) specifies the GET clause
Sort	LIMIT(long from, long count) Specifies the LIMIT class: from is the initial index, count is the number of results
<K> Sort	STORE(K destKey) Store the sort results in another key.

Methods inherited from interface org.jredis.Query

exec, execAsync

Method Detail

BY

<K> Sort BY(K pattern)

species the BY clause

GET

<K> Sort GET(K pattern)

specifies the GET clause

LIMIT

Sort LIMIT(long from,
           long count)

Specifies the LIMIT class: from is the initial index, count is the number of results

Parameters:

from - limit sort results to element at index 'from'

count - limit sort results to count - results will be result[from] to result[from+count], inclusve.

DESC

Sort DESC()

default sort is ASCending -- use this in your sort to specify DESC sort

ALPHA

Sort ALPHA()

sort is be default numeric -- use this to indicate lexiographic alphanumeric sort

STORE

<K> Sort STORE(K destKey)

Store the sort results in another key.

This command alters the semantics of the Query.exec() (or Query.execAsync()() to return a list of size 1, with the single entry being the long value representing the size of the created (store destination) list.

        // NOTE: this is a Long List - javadoc doesn't print the brackets.
        //
        List storeResult = DefaultCodec.toLong(jredis.sort(srcSet).DESC().STORE(destKey).exec());

        // the STORE() option changes result semantics -- now we expect our list to have a single entry
        // for the size of the stored list
        //
        size = sortedSet.get(0);
 
        System.out.format("Sorted list (size: %d):\n", size);