Chapter 19. Building a Query using the Ickle Query Language

Using Ickle, a light and small subset of JP-QL with full-text extensions, it is possible to create relational and full-text queries in both Library and Remote Client-Server mode. Ickle is a string-based querying language, and has the following characteristics:

To use the API, first obtain a QueryFactory to the cache and then call the .create() method, passing in the string to use in the query. For instance:

QueryFactory qf = Search.getQueryFactory(remoteCache);
Query q = qf.create("from sample_bank_account.Transaction where amount > 20");

QueryFactory qf = Search.getQueryFactory(remoteCache);
Query q = qf.create("from sample_bank_account.Transaction where amount > 20");

When using Ickle all fields used with full-text operators must be both Indexed and Analysed.

While Ickle is a subset of JP-QL it does have the following deviations in its query syntax:

To execute a fuzzy query add ~ along with an integer, representing the distance from the term used, after the term. For instance

Query fuzzyQuery = qf.create("from sample_bank_account.Transaction where description : 'cofee'~2");

Query fuzzyQuery = qf.create("from sample_bank_account.Transaction where description : 'cofee'~2");

To execute a range query define the given boundaries within a pair of braces, as seen in the following example:

Query rangeQuery = qf.create("from sample_bank_account.Transaction where amount : [20 to 50]");

Query rangeQuery = qf.create("from sample_bank_account.Transaction where amount : [20 to 50]");

A group of words may be searched by surrounding them in quotation marks, as seen in the following example:

Query q = qf.create("from sample_bank_account.Transaction where description : 'bus fare'");

Query q = qf.create("from sample_bank_account.Transaction where description : 'bus fare'");

To execute a proximity query, finding two terms within a specific distance, add a ~ along with the distance after the phrase. For instance, the following example will find the words canceling and fee provided they are not more than 3 words apart:

Query proximityQuery = qf.create("from sample_bank_account.Transaction where description : 'canceling fee'~3 ");

Query proximityQuery = qf.create("from sample_bank_account.Transaction where description : 'canceling fee'~3 ");

Both single-character and multi-character wildcard searches may be performed:

To search for text or test the following single-character wildcard search would be used:

Query wildcardQuery = qf.create("from sample_bank_account.Transaction where description : 'te?t'");

Query wildcardQuery = qf.create("from sample_bank_account.Transaction where description : 'te?t'");

To search for test, tests, or tester the following multi-character wildcard search would be useD:

Query wildcardQuery = qf.create("from sample_bank_account.Transaction where description : 'test*'");

Query wildcardQuery = qf.create("from sample_bank_account.Transaction where description : 'test*'");

Regular expression queries may be performed by specifing a pattern between /. Ickle uses Lucene’s regular expression syntax, so to search for the words moat or boat the following could be used:

Query regExpQuery = qf.create("from sample_library.Book  where title : /[mb]oat/");

Query regExpQuery = qf.create("from sample_library.Book  where title : /[mb]oat/");

Terms may be boosted by adding a ^ after the term to increase their relevance in a given query, the higher the boost factor the more relevant the term will be. For instance to search for titles containing beer and wine with a higher relevance on beer, by a factor of 3, the following could be used:

Query boostedQuery = qf.create("from sample_library.Book where title : beer^3 OR wine");

Query boostedQuery = qf.create("from sample_library.Book where title : beer^3 OR wine");