Chapter 16. The Infinispan Query DSL
The Infinispan Query DSL provides an unified way of querying a cache. It can be used in Library mode for both indexed and indexless queries, as well as for Remote Querying (via the Hot Rod Java client). The Infinispan Query DSL allows queries without relying on Lucene native query API or Hibernate Search query API.
Indexless queries are only available with the Infinispan Query DSL for both the JBoss Data Grid remote and embedded mode. Indexless queries do not require a configured index (see Section 16.2, “Enabling Infinispan Query DSL-based Queries”). The Hibernate Search/Lucene-based API cannot use indexless queries.
16.1. Creating Queries with Infinispan Query DSL
The new query API is located in the org.infinispan.query.dsl package. A query is created with the assistance of the
QueryFactory instance, which is obtained using Search.getQueryFactory(). Each QueryFactory instance is bound to the one cache instance, and is a stateless and thread-safe object that can be used for creating multiple parallel queries.
The Infinispan Query DSL uses the following steps to perform a query.
- A query is created by invocating the
from(Class entityType)method, which returns aQueryBuilderobject that is responsible for creating queries for the specified entity class from the given cache. - The
QueryBuilderaccumulates search criteria and configuration specified through invoking its DSL methods, and is used to build aQueryobject by invoking theQueryBuilder.build()method, which completes the construction. TheQueryBuilderobject cannot be used for constructing multiple queries at the same time except for nested queries, however it can be reused afterwards. - Invoke the
list()method of theQueryobject to execute the query and fetch the results. Once executed, theQueryobject is not reusable. If new results must be fetched, a new instance must be obtained by callingQueryBuilder.build().
Important
A query targets a single entity type and is evaluated over the contents of a single cache. Running a query over multiple caches, or creating queries targeting several entity types is not supported.
