pagination

Author: icreated

src/main/kotlin/com/cosmotech/api/utils/RedisUtils.kt

@@ -0,0 +1,28 @@
+// Copyright (c) Cosmo Tech.
+// Licensed under the MIT license.
+package com.cosmotech.api.utils
+
+import org.springframework.data.domain.PageRequest
+
+fun constructPageRequest(page: Int?, size: Int?, maxSize: Int): PageRequest? {
+  return when {
+    page != null && size != null -> PageRequest.of(page, size)
+    page != null && size == null -> PageRequest.of(page, maxSize)
+    page == null && size != null -> PageRequest.of(0, size)
+    else -> null
+  }
+}
+
+fun <T> findAllPaginated(
+    maxResult: Int,
+    findAllLambda: (pageRequest: PageRequest) -> MutableList<T>
+): MutableList<T> {
+  var pageRequest = PageRequest.ofSize(maxResult)
+  var connectorList = mutableListOf<T>()
+  do {
+    var objectList = findAllLambda(pageRequest)
+    pageRequest = pageRequest.next()
+    connectorList.addAll(objectList)
+  } while (objectList.isNotEmpty())
+  return connectorList
+}

src/test/kotlin/com/cosmotech/api/utils/AnyExtTests.kt renamed to src/test/kotlin/com/cosmotech/api/utils/AnyExtensionsTests.kt

@@ -10,7 +10,7 @@ import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 import org.junit.jupiter.api.assertThrows
 
-class AnyExtTests {
+class AnyExtensionsTests {
 
   @Test
   fun `changed - change when comparing null to non-null`() {

src/test/kotlin/com/cosmotech/api/utils/RedisUtilsTests.kt

@@ -0,0 +1,46 @@
+// Copyright (c) Cosmo Tech.
+// Licensed under the MIT license.
+package com.cosmotech.api.utils
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import org.springframework.data.domain.PageRequest
+
+const val DEFAULT_MAX_PAGE_SIZE = 100
+
+class RedisUtilsTests {
+
+  @Test
+  fun `constructPageRequest - should check multiple cases for page and size`() {
+    listOf(
+            Pair(1, 10) to PageRequest.of(1, 10),
+            Pair(null, 10) to PageRequest.of(0, 10),
+            Pair(1, null) to PageRequest.of(1, DEFAULT_MAX_PAGE_SIZE),
+            Pair(null, null) to null)
+        .forEach { (input, expected) ->
+          val actual = constructPageRequest(input.first, input.second, DEFAULT_MAX_PAGE_SIZE)
+          assertEquals(expected, actual)
+        }
+  }
+
+  @Test
+  fun `findAllPaginated - should check empty List`() {
+    val maxResult = 100
+    val findAllLambda = { _: PageRequest -> mutableListOf<Any>() }
+    val actual = findAllPaginated(maxResult, findAllLambda)
+    assertEquals(0, actual.size)
+  }
+
+  @Test
+  fun `findAllPaginated - should check non-empty List`() {
+    var counter = 3
+    val findAllLambda = { _: PageRequest ->
+      if (counter-- == 0) mutableListOf() else mutableListOf(Any(), Any(), Any(), Any(), Any())
+    }
+    listOf(5, 10, 15, 20, 50).forEach { maxResult ->
+      counter = 3
+      val actual = findAllPaginated(maxResult, findAllLambda)
+      assertEquals(15, actual.size)
+    }
+  }
+}