com.orm.androrm.migration.MigrationHelper.java Source code

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Here is the source code for com.orm.androrm.migration.MigrationHelper.java

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/**
 *    Copyright (c) 2012 Philipp Giese
 *
 * 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 com.orm.androrm.migration;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang3.StringUtils;

import android.content.Context;
import android.database.Cursor;

import com.orm.androrm.DatabaseAdapter;
import com.orm.androrm.DatabaseBuilder;
import com.orm.androrm.Model;
import com.orm.androrm.field.ManyToManyField;

public class MigrationHelper {

    private DatabaseAdapter mAdapter;

    public MigrationHelper(Context context) {
        mAdapter = DatabaseAdapter.getInstance(context);
    }

    private Cursor getCursor(String query) {
        mAdapter.open();
        return mAdapter.query(query);
    }

    private void close(Cursor cursor) {
        cursor.close();
        mAdapter.close();
    }

    public boolean hasField(Class<? extends Model> model, String name) {
        String table = DatabaseBuilder.getTableName(model);
        String sql = "PRAGMA TABLE_INFO(`" + table + "`)";

        Cursor c = getCursor(sql);

        while (c.moveToNext()) {
            String fieldName = c.getString(c.getColumnIndexOrThrow("name"));

            if (fieldName.equals(name)) {
                close(c);
                return true;
            }
        }

        close(c);
        return false;
    }

    public boolean tableExists(Class<? extends Model> model) {
        return tableExists(DatabaseBuilder.getTableName(model));
    }

    /**
     * Checks whether a given table name already exists in the database.
     * 
     * @param name Name of the table to look up.
     * @return <code>true</code> if one exists <code>false</code> otherwise.
     */
    public boolean tableExists(String name) {
        String sql = "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE '" + name + "'";

        Cursor c = getCursor(sql);

        while (c.moveToNext()) {
            String table = c.getString(c.getColumnIndexOrThrow("name"));

            if (table.equalsIgnoreCase(name)) {
                close(c);

                return true;
            }
        }

        close(c);
        return false;
    }

    /**
     * Check if a given model has relational tables in the system. 
     * Relational tables are created if a model has one or more 
     * {@link ManyToManyField} instances. 
     * 
     * @param model The {@link Model} class to look up. 
     * @return <code>true</code> if there are any, <code>false</code> otherwise.
     */
    public boolean hasRelationTable(Class<? extends Model> model) {
        return hasRelationTable(DatabaseBuilder.getTableName(model));
    }

    /**
     * Alias for {@link MigrationHelper#hasRelationTable(Class)}.
     * @param name String
     * @return boolean
     */
    public boolean hasRelationTable(String name) {
        return !getRelationTableNames(name).isEmpty();
    }

    public List<String> getRelationTableNames(String table) {
        List<String> result = new ArrayList<String>();
        String sql = "SELECT name FROM sqlite_master WHERE type='table' AND (name LIKE '" + table
                + "#_%' OR name LIKE '%#_" + table + "' ESCAPE '#')";

        Cursor c = getCursor(sql);

        while (c.moveToNext()) {
            String name = c.getString(c.getColumnIndexOrThrow("name"));

            if (!name.equalsIgnoreCase(table) && (StringUtils.startsWithIgnoreCase(name, table)
                    || StringUtils.endsWithIgnoreCase(name, table))) {

                result.add(name);
            }
        }

        close(c);
        return result;
    }
}