migrate to a proper db helper class, sub-classed from SQLiteOpenHelper

[mobile-ledger.git] / app / src / main / java / net / ktnx / mobileledger / MobileLedgerDatabase.java

diff --git a/app/src/main/java/net/ktnx/mobileledger/MobileLedgerDatabase.java b/app/src/main/java/net/ktnx/mobileledger/MobileLedgerDatabase.java
new file mode 100644 (file)
index 0000000..301b946
--- /dev/null
+++ b/app/src/main/java/net/ktnx/mobileledger/MobileLedgerDatabase.java
@@ -0,0 +1,140 @@
+package net.ktnx.mobileledger;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.database.Cursor;
+import android.database.SQLException;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Locale;
+
+class MobileLedgerDatabase extends SQLiteOpenHelper implements AutoCloseable {
+    static final String DB_NAME = "mobile-ledger.db";
+    static final String ACCOUNTS_TABLE = "accounts";
+    static final String DESCRIPTION_HISTORY_TABLE = "description_history";
+    static final int LATEST_REVISION = 4;
+
+    final Context mContext;
+
+    public
+    MobileLedgerDatabase(Context context) {
+        super(context, DB_NAME, null, LATEST_REVISION);
+        Log.d("db", "creating helper instance");
+        mContext = context;
+    }
+
+    @Override
+    public
+    void onCreate(SQLiteDatabase db) {
+        Log.d("db", "onCreate called");
+        onUpgrade(db, -1, LATEST_REVISION);
+    }
+
+    @Override
+    public
+    void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        Log.d("db", "onUpgrade called");
+        for(int i = oldVersion+1; i <= newVersion; i++) applyRevision(db, i);
+    }
+
+    private void applyRevision(SQLiteDatabase db, int
+            rev_no) {
+        final Resources rm = mContext.getResources();
+        String rev_file = String.format(Locale.US, "sql_%d", rev_no);
+
+        int res_id = rm.getIdentifier(rev_file, "raw", mContext.getPackageName());
+        if (res_id == 0)
+            throw new SQLException(String.format(Locale.US, "No resource for revision %d", rev_no));
+        db.beginTransaction();
+        try (InputStream res = rm.openRawResource(res_id)) {
+            Log.d("db", "Applying revision " + String.valueOf(rev_no));
+            InputStreamReader isr = new InputStreamReader(res);
+            BufferedReader reader = new BufferedReader(isr);
+
+            String line;
+            while ((line = reader.readLine()) != null) {
+                db.execSQL(line);
+            }
+
+            db.setTransactionSuccessful();
+        }
+        catch (IOException e) {
+            Log.e("db", String.format("Error opening raw resource for revision %d", rev_no));
+            e.printStackTrace();
+        }
+        finally {
+            db.endTransaction();
+        }
+    }
+    int get_option_value(String name, int default_value) {
+        String s = get_option_value(name, String.valueOf(default_value));
+        try {
+            return Integer.parseInt(s);
+        }
+        catch (Exception e) {
+            return default_value;
+        }
+    }
+
+    long get_option_value(String name, long default_value) {
+        String s = get_option_value(name, String.valueOf(default_value));
+        try {
+            return Long.parseLong(s);
+        }
+        catch (Exception e) {
+            Log.d("db", "returning default long value of "+name, e);
+            return default_value;
+        }
+    }
+
+    String get_option_value(String name, String default_value) {
+        Log.d("db", "about to fetch option "+name);
+        try(SQLiteDatabase db = getReadableDatabase()) {
+            try (Cursor cursor = db
+                    .rawQuery("select value from options where name=?", new String[]{name}))
+            {
+                if (cursor.moveToFirst()) {
+                    String result = cursor.getString(0);
+
+                    if (result == null) result = default_value;
+
+                    Log.d("db", "option " + name + "=" + result);
+                    return result;
+                }
+                else return default_value;
+            }
+            catch (Exception e) {
+                Log.d("db", "returning default value for " + name, e);
+                return default_value;
+            }
+        }
+    }
+
+     void set_option_value(String name, String value) {
+        Log.d("db", "setting option "+name+"="+value);
+        try(SQLiteDatabase db = getWritableDatabase()) {
+            db.execSQL("insert or replace into options(name, value) values(?, ?);",
+                    new String[]{name, value});
+        }
+    }
+
+    void set_option_value(String name, long value) {
+        set_option_value(name, String.valueOf(value));
+    }
+    static long get_option_value(Context context, String name, long default_value) {
+        try(MobileLedgerDatabase db = new MobileLedgerDatabase(context)) {
+            return db.get_option_value(name, default_value);
+        }
+    }
+    static void set_option_value(Context context, String name, String value) {
+        try(MobileLedgerDatabase db = new MobileLedgerDatabase(context)) {
+            db.set_option_value(name, value);
+        }
+    }
+}