16.6. Using Named Parameters

Instead of creating a new query for every request it is possible to include parameters in the query which may be replaced with each execution. This allows a query to be defined a single time and adjust variables in the query as needed.

Parameters are defined when the query is created by using the Expression.param(...) operator on the right hand side of any comparison operator from the having(...):

Example 16.6. Defining Named Parameters

import org.infinispan.query.Search;
import org.infinispan.query.dsl.*;
[...]

QueryFactory queryFactory = Search.getQueryFactory(cache);
// Defining a query to search for various authors
Query query = queryFactory.from(Book.class)
    .select("title")
    .having("author").eq(Expression.param("authorName"))
    .toBuilder()
    .build()
[...]

import org.infinispan.query.Search;
import org.infinispan.query.dsl.*;
[...]

QueryFactory queryFactory = Search.getQueryFactory(cache);
// Defining a query to search for various authors
Query query = queryFactory.from(Book.class)
    .select("title")
    .having("author").eq(Expression.param("authorName"))
    .toBuilder()
    .build()
[...]

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Setting the values of Named Parameters

By default all declared parameters are null, and all defined parameters must be updated to non-null values before the query must be executed. Once the parameters have been declared they may then be updated by invoking either setParameter(parameterName, value) or setParameters(parameterMap) on the query with the new values; in addition, the query does not need to be rebuilt. It may be executed again after the new parameters have been defined.

Example 16.7. Updating Parameters Individually

[...]
query.setParameter("authorName","Smith");

// Rerun the query and update the results
resultList = query.list();
[...]

[...]
query.setParameter("authorName","Smith");

// Rerun the query and update the results
resultList = query.list();
[...]

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Example 16.8. Updating Parameters as a Map

[...]
parameterMap.put("authorName","Smith");

query.setParameters(parameterMap);

// Rerun the query and update the results
resultList = query.list();
[...]

[...]
parameterMap.put("authorName","Smith");

query.setParameters(parameterMap);

// Rerun the query and update the results
resultList = query.list();
[...]

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16.6. Using Named Parameters

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