From 0f320a24b3212b30584b8eb6eb364dba04e41c81 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Tue, 18 Oct 2016 22:08:13 +0200
Subject: [PATCH] Add fallback query

---
 .../rhynodge/queries/FallbackQuery.kt              |  26 ++++++
 .../rhynodge/queries/FallbackQueryTest.kt          | 101 +++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 src/main/java/net/pterodactylus/rhynodge/queries/FallbackQuery.kt
 create mode 100644 src/test/kotlin/net/pterodactylus/rhynodge/queries/FallbackQueryTest.kt

diff --git a/src/main/java/net/pterodactylus/rhynodge/queries/FallbackQuery.kt b/src/main/java/net/pterodactylus/rhynodge/queries/FallbackQuery.kt
new file mode 100644
index 0000000..6e5fbd1
--- /dev/null
+++ b/src/main/java/net/pterodactylus/rhynodge/queries/FallbackQuery.kt
@@ -0,0 +1,26 @@
+package net.pterodactylus.rhynodge.queries
+
+import net.pterodactylus.rhynodge.Query
+import net.pterodactylus.rhynodge.State
+import net.pterodactylus.rhynodge.states.FailedState
+
+/**
+ * [Query] that can run a number of other [Query]s, returning the first successful [State] that is encountered.
+ *
+ * @author [David ‘Bombe’ Roden](mailto:bombe@pterodactylus.net)
+ */
+class FallbackQuery(private vararg val queries: Query) : Query {
+
+	init {
+		if (queries.isEmpty()) {
+			throw IllegalArgumentException("queries must not be empty")
+		}
+	}
+
+	override fun state(): State {
+		var lastFailedState: State = FailedState()
+		queries.asSequence().map(Query::state).forEach { lastFailedState = it; if (it.success()) return it }
+		return lastFailedState
+	}
+
+}
diff --git a/src/test/kotlin/net/pterodactylus/rhynodge/queries/FallbackQueryTest.kt b/src/test/kotlin/net/pterodactylus/rhynodge/queries/FallbackQueryTest.kt
new file mode 100644
index 0000000..209454d
--- /dev/null
+++ b/src/test/kotlin/net/pterodactylus/rhynodge/queries/FallbackQueryTest.kt
@@ -0,0 +1,101 @@
+package net.pterodactylus.rhynodge.queries
+
+import net.pterodactylus.rhynodge.Query
+import net.pterodactylus.rhynodge.State
+import net.pterodactylus.rhynodge.states.AbstractState
+import net.pterodactylus.rhynodge.states.FailedState
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.Matchers.`is`
+import org.hamcrest.Matchers.sameInstance
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.ExpectedException
+import org.mockito.Mockito.`when`
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.never
+import org.mockito.Mockito.verify
+
+/**
+ * Unit test for [FallbackQuery].
+ *
+ * @author [David ‘Bombe’ Roden](mailto:bombe@pterodactylus.net)
+ */
+class FallbackQueryTest {
+
+	@JvmField @Rule val expectedException = ExpectedException.none()!!
+
+	private val firstQuery = mock(Query::class.java)
+	private val secondQuery = mock(Query::class.java)
+	private val thirdQuery = mock(Query::class.java)
+	private val query = FallbackQuery(firstQuery, secondQuery, thirdQuery)
+
+	private fun setupQueries(firstState: State = FailedState(), secondState: State = FailedState(), thirdState: State = FailedState()) {
+		`when`(firstQuery.state()).thenReturn(firstState)
+		`when`(secondQuery.state()).thenReturn(secondState)
+		`when`(thirdQuery.state()).thenReturn(thirdState)
+	}
+
+	@Test
+	fun `fallback query returns state of third query`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(thirdState = successState)
+		assertThat(query.state(), sameInstance<State>(successState))
+	}
+
+	@Test
+	fun `fallback query calls all three queries`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(thirdState = successState)
+		query.state()
+		verify(firstQuery).state()
+		verify(secondQuery).state()
+		verify(thirdQuery).state()
+	}
+
+	@Test
+	fun `fallback query returns second state`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(secondState = successState)
+		assertThat(query.state(), sameInstance<State>(successState))
+	}
+
+	@Test
+	fun `fallback query does not query third query`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(secondState = successState)
+		query.state()
+		verify(firstQuery).state()
+		verify(secondQuery).state()
+		verify(thirdQuery, never()).state()
+	}
+
+	@Test
+	fun `fallback query returns first state`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(firstState = successState)
+		assertThat(query.state(), sameInstance<State>(successState))
+	}
+
+	@Test
+	fun `fallback query does not query second and third query`() {
+		val successState: AbstractState = object : AbstractState() {}
+		setupQueries(firstState = successState)
+		query.state()
+		verify(firstQuery).state()
+		verify(secondQuery, never()).state()
+		verify(thirdQuery, never()).state()
+	}
+
+	@Test
+	fun `fallback query returns failed state if no query succeeds`() {
+		setupQueries()
+		assertThat(query.state().success(), `is`(false))
+	}
+
+	@Test
+	fun `fallback query can not be created without queries`() {
+		expectedException.expect(IllegalArgumentException::class.java)
+		FallbackQuery()
+	}
+
+}
-- 
2.7.4