Added initial read, create, and delete functions

src/main/kotlin/service/LibraryService.kt

@@ -2,25 +2,67 @@ package codes.kalar.service
 
 import codes.kalar.exception.DbElementInsertionException
 import codes.kalar.exception.DbElementNotFoundException
+import codes.kalar.model.Library
+import codes.kalar.model.NewLibrary
 import kotlinx.serialization.json.Json
 import java.sql.*
 
 class LibraryService(private val connection: Connection) {
 
     companion object {
-        private const val SELECT_LIBRARY_BY_ID = ""
-        private const val INSERT_LIBRARY = ""
+        private const val SELECT_LIBRARY_BY_ID = "SELECT * FROM library WHERE  id = ?"
+        private const val SELECT_LIBRARY_ALL = "SELECT * FROM library ORDER BY id DESC LIMIT 25"
+        private const val INSERT_LIBRARY = "INSERT INTO library (name, address) VALUES (?, ?)"
         private const val UPDATE_LIBRARY_BY_ID = ""
         // In the event  are "deleted" erroneously, having a flag set instead of actually removing the entry allows
         // for quick reversal.
         private const val ARCHIVE_LIBRARY_BY_ID = ""
     }
 
-    suspend fun create() {}
+    suspend fun create(library: NewLibrary): Long {
+        val statement = connection.prepareStatement(INSERT_LIBRARY, Statement.RETURN_GENERATED_KEYS)
+        statement.setString(1, library.name)
+        statement.setString(2, library.address)
+        try {
+            statement.execute()
+            val key = statement.generatedKeys
+            if (key.next()) {
+                return key.getLong(1)
+            }
+            return -1
+        } catch (cause: SQLException) {
+            throw DbElementInsertionException("Could not insert library: ${cause.message}")
+        }
+    }
 
-    suspend fun read() {}
+    suspend fun read(id: Long): Library {
+        val statement = connection.prepareStatement(SELECT_LIBRARY_BY_ID)
+        statement.setLong(1, id)
+        try {
+            val resultSet = statement.executeQuery()
+            if (resultSet.next() && resultSet.getBoolean("is_archived")) {
+                return createLibraryFromResult(resultSet)
+            } else {
+                throw DbElementNotFoundException("Could not find collection item. resultSet: $resultSet")
+            }
+        } catch(cause: SQLException) {
+            throw DbElementNotFoundException("Could not find collection item with id $id")
+        }
+    }
 
-    suspend fun update() {}
+    suspend fun update(library: Library) {}
 
-    suspend fun delete() {}
+    suspend fun delete(id: String) {}
+
+    fun createLibraryFromResult(resultSet: ResultSet): Library {
+        try {
+            val id = resultSet.getLong("id")
+            val name = resultSet.getString("name")
+            val address = resultSet.getString("address")
+            val isArchived = resultSet.getBoolean("is_archived")
+            return Library(id, name, address, isArchived)
+        } catch (cause: NullPointerException) {
+            throw DbElementInsertionException("${cause.message}\nresultSet = ${resultSet.metaData}")
+        }
+    }
 }