StarContentProvider.java

/**
 * Copyright (C) 2013 by Raphael Michel under the MIT license:
 *
 * 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.
 */
package de.geeksfactory.opacclient.storage;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;

import java.util.List;

import de.geeksfactory.opacclient.BuildConfig;

public class StarContentProvider extends ContentProvider {
    public static final String STAR_TYPE = "star";
    private static final String STAR_MIME_POSTFIX = "/vnd.de.opacapp.type"
            + STAR_TYPE;
    public static final String AUTHORITY = BuildConfig.APPLICATION_ID + ".starprovider";
    public static final String BASE_URI = "content://" + AUTHORITY + "/";
    public static final Uri STAR_URI = Uri.parse(BASE_URI + STAR_TYPE);
    private static final String MIME_PREFIX = "vnd.android.cursor.";
    private static final String STAR_DIR_MIME = MIME_PREFIX + "dir"
            + STAR_MIME_POSTFIX;
    private static final String STAR_ITEM_MIME = MIME_PREFIX + "item"
            + STAR_MIME_POSTFIX;
    private StarDatabase database;

    private static Mime getTypeMime(Uri uri) {
        if (!AUTHORITY.equals(uri.getAuthority())
                && !uri.getAuthority().startsWith("de.opacapp.")
                && !uri.getAuthority().startsWith("net.opacapp.")) {
            return null;
        }
        List<String> segments = uri.getPathSegments();
        if (segments == null || segments.size() == 0) {
            return null;
        }

        String type = segments.get(0);
        if (STAR_TYPE.equals(type)) {
            switch (segments.size()) {
                case 1:
                    return Mime.STAR_DIR;
                case 2:
                    return Mime.STAR_ITEM;
                default:
                    return null;
            }
        } else {
            return null;
        }
    }

    @Override
    public boolean onCreate() {
        database = new StarDatabase(getContext());
        return true;
    }

    @Override
    public String getType(Uri uri) {
        switch (getTypeMime(uri)) {
            case STAR_DIR:
                return STAR_DIR_MIME;
            case STAR_ITEM:
                return STAR_ITEM_MIME;
            default:
                return null;
        }
    }

    private int deleteInDatabase(String table, String whereClause,
            String[] whereArgs) {
        return database.getWritableDatabase().delete(table, whereClause, whereArgs);
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        int rowsAffected;
        switch (getTypeMime(uri)) {
            case STAR_DIR:
                rowsAffected = deleteInDatabase(StarDatabase.STAR_TABLE, selection, selectionArgs);
                break;
            case STAR_ITEM:
                rowsAffected = deleteInDatabase(StarDatabase.STAR_TABLE,
                        StarDatabase.STAR_WHERE_ID, selectionForUri(uri));
                break;
            default:
                rowsAffected = 0;
                break;
        }

        if (rowsAffected > 0) {
            notifyUri(uri);
        }
        return rowsAffected;
    }

    private long insertIntoDatabase(String table, ContentValues values) {
        return database.getWritableDatabase()
                       .insertOrThrow(table, null, values);
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        Uri itemUri;
        long id;
        switch (getTypeMime(uri)) {
            case STAR_DIR:
                id = insertIntoDatabase(StarDatabase.STAR_TABLE, values);
                itemUri = ContentUris.withAppendedId(STAR_URI, id);
                notifyUri(STAR_URI);
                break;
            case STAR_ITEM:
            default:
                itemUri = null;
                break;
        }
        if (itemUri != null) {
            notifyUri(uri);
        }
        return itemUri;
    }

    private Cursor queryDatabase(String table, String[] projection,
            String selection, String[] selectionArgs, String groupBy,
            String having, String orderBy) {
        return database.getReadableDatabase().query(table, projection,
                selection, selectionArgs, groupBy, having, orderBy);
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
        Cursor cursor;
        switch (getTypeMime(uri)) {
            case STAR_DIR:
                cursor = queryDatabase(StarDatabase.STAR_TABLE, projection,
                        selection, selectionArgs, null, null, sortOrder);
                break;
            case STAR_ITEM:
                cursor = queryDatabase(StarDatabase.STAR_TABLE, projection,
                        StarDatabase.STAR_WHERE_ID, selectionForUri(uri), null,
                        null, sortOrder);
                break;
            default:
                return null;
        }
        cursor.setNotificationUri(getContext().getContentResolver(), uri);
        return cursor;
    }

    private int updateInDatabase(String table, ContentValues values,
            String selection, String[] selectionArgs) {
        return database.getWritableDatabase().update(table, values, selection,
                selectionArgs);
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {
        int rowsAffected;
        switch (getTypeMime(uri)) {
            case STAR_DIR:
                rowsAffected = updateInDatabase(StarDatabase.STAR_TABLE, values,
                        selection, selectionArgs);
                break;
            case STAR_ITEM:
                rowsAffected = updateInDatabase(StarDatabase.STAR_TABLE, values,
                        StarDatabase.STAR_WHERE_ID, selectionForUri(uri));
                break;
            default:
                rowsAffected = 0;
                break;
        }

        if (rowsAffected > 0) {
            notifyUri(uri);
        }
        return rowsAffected;
    }

    private void notifyUri(Uri uri) {
        getContext().getContentResolver().notifyChange(uri, null);
    }

    private String[] selectionForUri(Uri uri) {
        return new String[]{String.valueOf(ContentUris.parseId(uri))};
    }

    private enum Mime {
        STAR_ITEM, STAR_DIR
    }
}