Add Optional Validate Lambda to stringPref

ZenitechSoftware · May 10, 2019 · f9c9462 · f9c9462
1 parent f5ef7a4
commit f9c9462
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Showing 5 changed files with 33 additions and 3 deletions.
diff --git a/krate/src/androidTest/java/hu/autsoft/krate/OptionalTests.kt b/krate/src/androidTest/java/hu/autsoft/krate/OptionalTests.kt
@@ -2,6 +2,7 @@ package hu.autsoft.krate
 
 import android.support.test.InstrumentationRegistry.getTargetContext
 import android.support.test.runner.AndroidJUnit4
+import hu.autsoft.krate.exception.KrateValidationException
 import org.junit.Assert.assertEquals
 import org.junit.Before
 import org.junit.Test
@@ -103,4 +104,18 @@ class OptionalTests {
         assertEquals(null, testKrate.optionalStringSet)
     }
 
+    @Test(expected = KrateValidationException::class)
+    fun testOptionalStringValidatedPrefFailsValidation() {
+        assertEquals(null, testKrate.optionalValidatedString)
+
+        testKrate.optionalValidatedString = "Lorem ipsum dolor sit amet"
+    }
+
+    @Test
+    fun testOptionalStringValidatedPassesValidation() {
+        assertEquals(null, testKrate.optionalValidatedString)
+
+        testKrate.optionalValidatedString = "Lorem"
+    }
+
 }
diff --git a/krate/src/androidTest/java/hu/autsoft/krate/TestKrate.kt b/krate/src/androidTest/java/hu/autsoft/krate/TestKrate.kt
@@ -14,5 +14,8 @@ class TestKrate(context: Context) : SimpleKrate(context) {
     var optionalLong by longPref("optionalLong")
     var optionalString by stringPref("optionalString")
     var optionalStringSet by stringSetPref("optionalStringSet")
+    var optionalValidatedString by stringPref("validatedString") {
+        it?.length ?: 5 == 5
+    }
 
 }
diff --git a/krate/src/main/kotlin/hu/autsoft/krate/Functions.kt b/krate/src/main/kotlin/hu/autsoft/krate/Functions.kt
@@ -46,9 +46,14 @@ public fun Krate.longPref(key: String): ReadWriteProperty<Krate, Long?> {
 
 /**
  * Creates an optional preference of type String with the given [key] in this [Krate] instance.
+ *
+ * @param [key] the key to identify this value in SharedPreferences
+ * @param [isValid] the validation function to be used when setting this property
+ *
+ * @return [StringDelegate]
  */
-public fun Krate.stringPref(key: String): ReadWriteProperty<Krate, String?> {
-    return StringDelegate(key)
+public fun Krate.stringPref(key: String, isValid: (String?) -> Boolean = { true }): ReadWriteProperty<Krate, String?> {
+    return StringDelegate(key, isValid)
 }
 
 /**

diff --git a/krate/src/main/kotlin/hu/autsoft/krate/exception/KrateValidationException.kt b/krate/src/main/kotlin/hu/autsoft/krate/exception/KrateValidationException.kt
@@ -0,0 +1,3 @@
+package hu.autsoft.krate.exception
+
+class KrateValidationException(message: String) : Exception(message)
diff --git a/krate/src/main/kotlin/hu/autsoft/krate/optional/StringDelegate.kt b/krate/src/main/kotlin/hu/autsoft/krate/optional/StringDelegate.kt
@@ -1,12 +1,14 @@
 package hu.autsoft.krate.optional
 
 import hu.autsoft.krate.Krate
+import hu.autsoft.krate.exception.KrateValidationException
 import hu.autsoft.krate.util.edit
 import kotlin.properties.ReadWriteProperty
 import kotlin.reflect.KProperty
 
 internal class StringDelegate(
-        private val key: String
+        private val key: String,
+        private val isValid: (String?) -> Boolean
 ) : ReadWriteProperty<Krate, String?> {
 
     override operator fun getValue(thisRef: Krate, property: KProperty<*>): String? {
@@ -18,6 +20,8 @@ internal class StringDelegate(
     }
 
     override operator fun setValue(thisRef: Krate, property: KProperty<*>, value: String?) {
+        if (!isValid(value)) throw KrateValidationException("$value not valid.")
+
         if (value == null) {
             thisRef.sharedPreferences.edit { remove(key) }
         } else {