https://github.com/ornicar/scala-paginator

Generic paginator for scala
https://github.com/ornicar/scala-paginator

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Generic paginator for scala

• Host: GitHub
• URL: https://github.com/ornicar/scala-paginator
• Owner: ornicar
• License: mit
• Created: 2011-10-13T18:00:49.000Z (about 13 years ago)
• Default Branch: master
• Last Pushed: 2012-07-03T12:59:19.000Z (over 12 years ago)
• Last Synced: 2023-03-10T21:18:15.762Z (over 1 year ago)
• Language: Scala
• Homepage:
• Size: 116 KB
• Stars: 6
• Watchers: 3
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

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README

        
# Generic paginator for scala

- Provides pagination for any data provider: DB, remote API, memory, ...

- Based on a simple adapter pattern.

- Fully functional.

## Example

```scala

import com.github.ornicar.paginator._

val adapter   = InMemoryAdapter('a' to 'z')

for {

  paginator <- Paginator(adapter, currentPage = 2, maxPerPage = 5).right

} {

  paginator.nbResults           // 26

  paginator.nbPages             // 6

  paginator.currentPageResults  // Vector('f', 'g', 'h', 'i', 'j')

  paginator.currentPage         // 2

  paginator.maxPerPage          // 5

  paginator.hasToPaginate       // True

  paginator.hasNextPage         // True

  paginator.hasPreviousPage     // True

  paginator.nextPage            // Some(3)

  paginator.previousPage        // Some(1)

}

```

## Adapters

### InMemoryAdapter

This basic implementation of the adapter paginates a `Seq`. Example:

```scala

val adapter = InMemoryAdapter('a' to 'z')

val paginator = Paginator(adapter)

```

`paginator` is an instance of `Either[String, Paginator[A]]` where the left part is a possible error message.

```scala

Paginator(adapter) // Right[Paginator[A]]

Paginator(adapter, 1, 10) // Right[Paginator[A]]

Paginator(adapter, 0, 10) // Left("Max per page must be greater than zero")

Paginator(adapter, 1, 0) // Left("Current page must be greater than zero")

```

### MongoDB Salat adapter

Allows to paginate on any MongoDB query:

```scala

import com.github.ornicar.paginator.SalatAdapter                // I assume you also import the salat stuff

case class Person(name: String)                                 // Say we have a basic model class

object PersonDAO extends SalatDAO[Person, ObjectId](collection) // And a DAO for the model

val query     = MongoDBObject("name" -> "Joe")                    // This is a normal salat query

val adapter   = SalatAdapter(PersonDAO, query)                    // And a shiny mongodb paginator adapter

val paginator = Paginator(adapter)

```

The adapter will take care of adding the `skip` and `limit` options

to the mongodb query.

To use this adapter, you must include the `salat-adapter` project.

## Create another adapter

To create a new adapter, just implement the 2 methods of this trait:

```scala

trait Adapter[A] {

  /**

   * Returns the number of results.

   */

  def nbResults: Int

  /**

   * Returns an slice of the results.

   *

   * @param   offset    The number of elements to skip, starting from zero

   * @param   length    The maximum number of elements to return

   */

  def slice(offset: Int, length: Int): Seq[A]

}

```

You may use the provided `InMemoryAdapter` and `SalatAdapter` as implementation examples.