https://github.com/apulbere/crop

a lightweight, zero dependency, and type-safe wrapper around Java Persistence Criteria API, which simplifies building queries, particularly useful within REST SQL (RSQL) context
https://github.com/apulbere/crop

jakarta jakarta-persistence java rsql

Last synced: 25 days ago
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a lightweight, zero dependency, and type-safe wrapper around Java Persistence Criteria API, which simplifies building queries, particularly useful within REST SQL (RSQL) context

• Host: GitHub
• URL: https://github.com/apulbere/crop
• Owner: apulbere
• License: apache-2.0
• Created: 2024-01-21T09:34:51.000Z (11 months ago)
• Default Branch: main
• Last Pushed: 2024-01-30T08:28:54.000Z (11 months ago)
• Last Synced: 2024-01-30T09:38:19.683Z (11 months ago)
• Topics: jakarta, jakarta-persistence, java, rsql
• Language: Java
• Homepage:
• Size: 16.6 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# CriteriaOperator (CrOp)

CriteriaOperator is a lightweight, zero dependency, and type-safe wrapper around Java Persistence Criteria API, which simplifies building queries, particularly useful within REST SQL (RSQL) context.

Example of REST query that can be interpreted by the library:

```shell

http://localhost:64503/pets?birthdate.gte=2010-01-11&nickname.like=Ba

```

Which results in the following select:

```sql

select

    p1_0.id,

    p1_0.birthdate,

    p1_0.name,

    p1_0.pet_type_id 

from

    pet p1_0 

where

    p1_0.name like ? escape '' 

    and p1_0.birthdate>=?

```

There are a couple of easy steps to achieve the above:

1. Add the dependency

```xml

    com.apulbere

    crop

    0.1.0

```

2. Define a DTO that contains all fields necessary for filtering. For example, if you want to do filtering on `String` type then you choose `StringCriteriaOperator` from `com.apulbere.crop.operator` package.

```java

@Getter

@Setter

public class PetSearchCriteria {

    private StringCriteriaOperator nickname;

    private LocalDateCriteriaOperator birthdate;

}

```

3. Create an instance of the service that will parse the query. It requires `EntityManager` in the constructor.

```java

@Bean

CriteriaOperatorService cropService(EntityManager entityManager) {

    return new CriteriaOperatorService(entityManager);

}

```

4. Finally, invoke the service's `create` method with the root entity and filter object. The result is a builder that lets you match the entity's meta-model with each field from the DTO. When done, execute the query.

```java

@GetMapping("/pets")

List search(PetSearchCriteria petSearchCriteria) {

    return cropService.create(Pet.class, petSearchCriteria)

            .match(PetSearchCriteria::getNickname, Pet_.name)

            .match(PetSearchCriteria::getBirthdate, Pet_.birthdate)

            .getResultList()

            .stream()

            .map(petMapper::map)

            .toList();

}

```

For full example and to see all the capabilities of the library checkout [pet-shop](https://github.com/apulbere/pet-shop-crop) demo repository.