← Index · ← File index · ← Prev · Next →

#1254: `DBResultIterator.kt`

projectforge-business/src/main/kotlin/org/projectforge/framework/persistence/api/impl/DBResultIterator.kt Result Iteration, projectforge-business/src/main/kotlin/org/projectforge/framework/persistence/api/impl/DBResultIterator.kt 102 lines · 58 code · 31 comments · 13 blank

Generic interface and implementations for iterating over database search results. Provides DBCriteriaResultIterator using Hibernate ScrollableResults with entity graph support, and DBEmptyResultIterator for empty query results.

Architecture

Interface

interface DBResultIterator<O : ExtendedBaseDO<Long>> {
    fun next(): O?
    fun sort(list: List<O>): List<O>
}

Implementations

Class	Description
`DBEmptyResultIterator`	Returns null for `next()`; identity sort. Used for queries with no results.
`DBCriteriaResultIterator`	Wraps `ScrollableResults` from `jakarta.persistence.Query`. Supports entity graph hints (`jakarta.persistence.loadgraph`) and flushes entity manager every 100 iterations. Catches exceptions in `next()` with error logging.

Constructor Dependencies (DBCriteriaResultIterator)

entityManager — JPA EntityManager for query creation and clearing
criteria CriteriaQuery<O> — the JPA Criteria query
resultPredicates List<DBPredicate> — post-query in-memory predicates
queryFilter QueryFilter — provides entity graph name via entityGraphName

Git History