refactor: remove April-2017 backwards-compat STRING branch from NamespaceTypeAdapter

app/src/main/java/fr/free/nrw/commons/wikidata/json/NamespaceTypeAdapter.kt

@@ -2,7 +2,6 @@ package fr.free.nrw.commons.wikidata.json
 
 import com.google.gson.TypeAdapter
 import com.google.gson.stream.JsonReader
-import com.google.gson.stream.JsonToken
 import com.google.gson.stream.JsonWriter
 import fr.free.nrw.commons.wikidata.model.page.Namespace
 import java.io.IOException
@@ -14,13 +13,5 @@ class NamespaceTypeAdapter : TypeAdapter<Namespace>() {
     }
 
     @Throws(IOException::class)
-    override fun read(reader: JsonReader): Namespace {
-        if (reader.peek() == JsonToken.STRING) {
-            // Prior to 3210ce44, we marshaled Namespace as the name string of the enum, instead of
-            // the code number. This introduces a backwards-compatible check for the string value.
-            // TODO: remove after April 2017, when all older namespaces have been deserialized.
-            return Namespace.valueOf(reader.nextString())
-        }
-        return Namespace.of(reader.nextInt())
-    }
+    override fun read(reader: JsonReader): Namespace = Namespace.of(reader.nextInt())
 }

app/src/main/java/fr/free/nrw/commons/wikidata/model/EnumCodeMap.kt

@@ -1,25 +1,12 @@
 package fr.free.nrw.commons.wikidata.model
 
-import android.util.SparseArray
-
 class EnumCodeMap<T>(
     enumeration: Class<T>,
 ) where T : Enum<T>, T : EnumCode {
-    private val map: SparseArray<T>
-
-    init {
-        map = codeToEnumMap(enumeration)
-    }
-
-    operator fun get(code: Int): T = map.get(code) ?: throw IllegalArgumentException("code=$code")
+    private val map: HashMap<Int, T> =
+        enumeration.enumConstants.associateByTo(HashMap()) { it.code() }
 
-    private fun codeToEnumMap(enumeration: Class<T>): SparseArray<T> {
-        val ret = SparseArray<T>()
-        for (value in enumeration.enumConstants) {
-            ret.put(value.code(), value)
-        }
-        return ret
-    }
+    operator fun get(code: Int): T = map[code] ?: throw IllegalArgumentException("code=$code")
 
-    fun size(): Int = map.size()
+    fun size(): Int = map.size
 }

app/src/test/kotlin/fr/free/nrw/commons/wikidata/json/NamespaceTypeAdapterTest.kt

@@ -0,0 +1,26 @@
+package fr.free.nrw.commons.wikidata.json
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+import fr.free.nrw.commons.wikidata.model.page.Namespace
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import java.io.StringReader
+import java.io.StringWriter
+
+class NamespaceTypeAdapterTest {
+    private val adapter = NamespaceTypeAdapter()
+
+    @Test
+    fun `reads integer namespace code`() {
+        val reader = JsonReader(StringReader("6"))
+        assertEquals(Namespace.FILE, adapter.read(reader))
+    }
+
+    @Test
+    fun `writes namespace as integer code`() {
+        val sw = StringWriter()
+        adapter.write(JsonWriter(sw), Namespace.FILE)
+        assertEquals("6", sw.toString())
+    }
+}