CursorHelper.java

package fr.tvbarthel.apps.sayitfromthesky.helpers;

import android.database.Cursor;

import com.google.gson.Gson;

import java.util.Arrays;

import fr.tvbarthel.apps.sayitfromthesky.models.Drawing;
import fr.tvbarthel.apps.sayitfromthesky.providers.contracts.DrawingContract;

/**
 * Static utility methods for dealing with cursor.
 */
public final class CursorHelper {

    private static final Gson GSON = new Gson();

    // Non-instantiability
    private CursorHelper() {
    }

    /**
     * Get a {@link java.lang.String} from a {@link android.database.Cursor}
     *
     * @param cursor       the {@link android.database.Cursor} from which the {@link java.lang.String} will be extracted.
     * @param columnName   the column name of the {@link java.lang.String}
     * @param defaultValue the default {@link java.lang.String} to use if the column name does not exist.
     * @return a {@link java.lang.String}
     */
    public static String getString(Cursor cursor, String columnName, String defaultValue) {
        final int columnIndex = cursor.getColumnIndex(columnName);
        if (columnIndex == -1) return defaultValue;
        return cursor.getString(columnIndex);
    }

    /**
     * Get a long from a {@link android.database.Cursor}.
     *
     * @param cursor       the {@link android.database.Cursor} from which the long will be extracted.
     * @param columnName   the column name of the long value.
     * @param defaultValue the default long value to use if the column name does not exist.
     * @return a long value
     */
    public static long getLong(Cursor cursor, String columnName, long defaultValue) {
        final int columnIndex = cursor.getColumnIndex(columnName);
        if (columnIndex == -1) return defaultValue;
        return cursor.getLong(columnIndex);
    }

    /**
     * Get an int from a {@link android.database.Cursor}.
     *
     * @param cursor       the {@link android.database.Cursor} from which the int will be extracted.
     * @param columnName   the column name of the int value.
     * @param defaultValue the default int value to use if the column name does not exist.
     * @return an int value
     */
    public static int getInt(Cursor cursor, String columnName, int defaultValue) {
        final int columnIndex = cursor.getColumnIndex(columnName);
        if (columnIndex == -1) return defaultValue;
        return cursor.getInt(columnIndex);
    }

    /**
     * Convert a {@link android.database.Cursor} to a {@link fr.tvbarthel.apps.sayitfromthesky.models.Drawing}
     *
     * @param cursor the {@link android.database.Cursor} to be converted.
     * @return a new {@link fr.tvbarthel.apps.sayitfromthesky.models.Drawing}
     */
    public static Drawing cursorToDrawing(Cursor cursor) {
        final int id = CursorHelper.getInt(cursor, DrawingContract.Columns.COLUMN_ID, Drawing.NON_VALID_ID);
        final String title = CursorHelper.getString(cursor, DrawingContract.Columns.COLUMN_TITLE, "");
        final long creationTime = CursorHelper.getLong(cursor, DrawingContract.Columns.COLUMN_CREATION_TIME, 0l);
        final String encodedPolylines = CursorHelper.getString(cursor, DrawingContract.Columns.COLUMN_ENCODED_POLYLINES, "");
        final String[] polylines = GSON.fromJson(encodedPolylines, String[].class);
        final Drawing drawing = new Drawing(title, creationTime, Arrays.asList(polylines));
        drawing.setId(id);
        return drawing;
    }

}