added README.md and small fixes

README.md

@@ -1,2 +1,127 @@
-# RoomMigrationsGenerator
-Automated Android Room ORM migrations generator with compile-time code generation
+# Roomigrant
+
+Roomigrant is a helper library to automatically generate Android Room library migrations using compile-time code generation.
+
+# How does it work?
+
+Roomigrant uses scheme files generated by Room library and generates migrations base on difference between them. This means that Room schem generation must be enabled in build.gradle file:
+
+```groovy
+android {
+    defaultConfig {
+        javaCompileOptions {
+            annotationProcessorOptions {
+                arguments = ["room.schemaLocation": "$projectDir/schemas".toString()]
+            }
+        }
+    }
+}
+```
+
+Then actual Roomigrant library and compiler should be added to dependencies (preferrably after room dependencies):
+
+```groovy
+dependencies {
+    // room
+    implementation 'android.arch.persistence.room:runtime:1.1.1'
+    kapt 'android.arch.persistence.room:compiler:1.1.1'
+
+    // roomigrant
+    compileOnly project(':RoomigrantLib')
+    kapt project(':RoomigrantCompiler')
+}
+```
+
+After that actual database class should be annotated to enable migrations generator:
+
+```kotlin
+@Database(version = 5, entities = [Object1Dbo::class, Object2Dbo::class])
+@GenerateRoomMigrations
+abstract class Database : RoomDatabase() {
+    // ...
+}
+```
+
+And finally migrations can be added to actual Room database creation:
+
+```kotlin
+Room.databaseBuilder(appContext, Database::class.java, "database.sqlite")
+		.addMigrations(*Database_Migrations.build())
+		.build()
+```
+
+# Default rules
+
+Roominator will try its best to migrate everything by itself. It default rules are:
+
+ - columns that have new affinity/type will use SQLite's CAST method
+ - null cells became not nullable will take default value for thir's affinity/type
+ - new columns will be initialized to default value
+ -- 0 for INTEGER
+ -- 0.0 for REAL
+ -- "" for TEXT or BLOB
+
+Because of SQLite limitations when any change other than adding new column is done:
+ - new merge table will be created
+ - data copied from original table to merge table
+ - original table will be removed
+ - merge table will be renamed back to original
+
+# Custom rules
+
+Sometimes it will be required to write custom migration rules. It can be done by adding classes to GenerateRoomMigrations annotation:
+
+```kotlin
+@Database(version = 5, entities = [Object1Dbo::class, Object2Dbo::class])
+@GenerateRoomMigrations(Rules::class)
+abstract class Database : RoomDatabase() {
+    // ...
+}
+```
+
+And after that adding methods annotated with FieldMigrationRule annotation to provided classes:
+
+```kotlin
+// version 3 had Object1Dbo.intVal column
+// version 4 has Object1Dbo.intValRenamed column
+@FieldMigrationRule(version1 = 3, version2 = 4, table = "Object1Dbo", field = "intValRenamed")
+fun migrate_3_4_Object1Dbo_intVal(): String {
+	return "`Object1Dbo`.`intVal`"
+}
+```
+
+Returned value will be injected as-is to final SQL statement when copying/updating that field.
+
+# Todos
+
+ - Add table and column names escaping
+ - Add foreign key support (currently they are completely ignored)
+ - Add OnMigrationStart and OnMigrationEnd annotated callbacks
+ - Add to Maven Central (if anyone will use this library at all)
+ - Some internal optimizations
+
+# License
+
+```
+MIT License
+
+Copyright (c) 2018 Rostyslav Lesovyi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+```

RoomigrantTest/schemas/dev.matrix.roomigrant.test.Database/5.json

@@ -2,7 +2,7 @@
   "formatVersion": 1,
   "database": {
     "version": 5,
-    "identityHash": "bc0fa74c1813d4ced25801545540915a",
+    "identityHash": "d51066cdc9a5e865378f2c5cb2f61699",
     "entities": [
       {
         "tableName": "Object1Dbo",
@@ -47,11 +47,31 @@
         },
         "indices": [],
         "foreignKeys": []
+      },
+      {
+        "tableName": "Object2Dbo",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "columnNames": [
+            "id"
+          ],
+          "autoGenerate": false
+        },
+        "indices": [],
+        "foreignKeys": []
       }
     ],
     "setupQueries": [
       "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
-      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, \"bc0fa74c1813d4ced25801545540915a\")"
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, \"d51066cdc9a5e865378f2c5cb2f61699\")"
     ]
   }
 }

RoomigrantTest/src/main/java/dev/matrix/roomigrant/test/Database.kt

@@ -7,8 +7,9 @@ import dev.matrix.roomigrant.GenerateRoomMigrations
 /**
  * @author matrixdev
  */
-@Database(version = 5, entities = [Object1Dbo::class])
+@Database(version = 5, entities = [Object1Dbo::class, Object2Dbo::class])
 @GenerateRoomMigrations(Rules::class)
 abstract class Database : RoomDatabase() {
 	abstract val object1Dao: Object1Dao
+	abstract val object2Dao: Object2Dao
 }