Add method to get a null value if provider does not hold a value anymore

th2-net · Oct 23, 2023 · f1e7eb3 · f1e7eb3
1 parent a43fc45
commit f1e7eb3
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Showing 3 changed files with 42 additions and 3 deletions.
diff --git a/src/main/java/com/exactpro/th2/common/schema/factory/AbstractCommonFactory.java b/src/main/java/com/exactpro/th2/common/schema/factory/AbstractCommonFactory.java
@@ -84,7 +84,6 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.atomic.AtomicReference;
 
 import static com.exactpro.cradle.CradleStorage.DEFAULT_MAX_MESSAGE_BATCH_SIZE;
 import static com.exactpro.cradle.CradleStorage.DEFAULT_MAX_TEST_EVENT_BATCH_SIZE;
@@ -186,6 +185,8 @@ public AbstractCommonFactory(FactorySettings settings) {
     public void start() {
         DefaultExports.initialize();
 
+        // init exporter
+        prometheusExporter.getOrNull();
         livenessMonitor.enable();
     }
 

diff --git a/src/main/kotlin/com/exactpro/th2/common/schema/factory/LazyProvider.kt b/src/main/kotlin/com/exactpro/th2/common/schema/factory/LazyProvider.kt
@@ -32,19 +32,32 @@ internal class LazyProvider<T : Any?> private constructor(
     }
 
     fun get(): T {
+        return getState().value
+    }
+
+    /**
+     * The difference from [get] method is that this one does not throw an exception
+     * if provider already closed.
+     * However, it will still throw an exception if value initialization is failed
+     */
+    fun getOrNull(): T? {
+        return getState().takeIf { it is State.Hold }?.value
+    }
+
+    private fun getState(): State<T> {
         return if (reference.compareAndSet(null, State.Init)) {
             val holder = State.Hold(initialize())
             if (!reference.compareAndSet(State.Init, holder)) {
                 onClose.consume(holder.value)
                 error("provider '$name' already closed")
             }
-            holder.value
+            holder
         } else {
             var currentState: State<T>?
             do {
                 currentState = reference.get()
             } while (currentState == State.Init || currentState == null)
-            currentState.value
+            currentState
         }
     }
 

diff --git a/src/test/kotlin/com/exactpro/th2/common/schema/factory/LazyProviderTest.kt b/src/test/kotlin/com/exactpro/th2/common/schema/factory/LazyProviderTest.kt
@@ -16,8 +16,13 @@
 
 package com.exactpro.th2.common.schema.factory
 
+import com.exactpro.th2.common.schema.exception.CommonFactoryException
 import org.junit.jupiter.api.Assertions
 import org.junit.jupiter.api.RepeatedTest
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
 import org.mockito.kotlin.doReturn
 import org.mockito.kotlin.inOrder
 import org.mockito.kotlin.mock
@@ -29,6 +34,8 @@ import java.util.concurrent.Callable
 import java.util.concurrent.ExecutionException
 import java.util.concurrent.ForkJoinPool
 import java.util.concurrent.ThreadLocalRandom
+import kotlin.test.assertContains
+import kotlin.test.assertNotNull
 
 internal class LazyProviderTest {
     @RepeatedTest(50)
@@ -132,4 +139,22 @@ internal class LazyProviderTest {
             "unexpected errors thrown: $errors"
         }
     }
+
+    @Test
+    fun `null resources`() {
+        val provider = LazyProvider.lazy<Int?>("test") { null }
+        Assertions.assertEquals(null, provider.get(), "unexpected value")
+    }
+
+    @ParameterizedTest
+    @ValueSource(booleans = [true, false])
+    fun `exception in supplier`(safeCall: Boolean) {
+        val provider = LazyProvider.lazy<Unit>("test") { error("supplier error") }
+        val ex = assertThrows<CommonFactoryException> {
+            if (safeCall) provider.getOrNull() else provider.get()
+        }
+        assertNotNull(ex.cause?.message, "no cause") {
+            assertContains(it, "supplier error")
+        }
+    }
 }