SqliteUtil.java

/**
 * Copyright (C) 2013 Johannes Schnatterer
 *
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This file is part of nusic.
 *
 * nusic is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * nusic is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with nusic.  If not, see <http://www.gnu.org/licenses/>.
 */
package info.schnatterer.nusic.data.util;

import info.schnatterer.nusic.data.NusicDatabaseSqlite;
import info.schnatterer.nusic.util.DateUtil;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import android.content.ContentValues;
import android.database.Cursor;
import android.os.Parcel;

public final class SqliteUtil {
    private static final Logger LOG = LoggerFactory
            .getLogger(NusicDatabaseSqlite.class);

    public static final Integer FALSE = Integer.valueOf(0);
    public static final Integer TRUE = Integer.valueOf(1);

    private SqliteUtil() {
    }

    /**
     * Wrapper for {@link ContentValues}'s <code>putTYPE()</code> methods only
     * puts values != <code>null</code>. This is helpful when updating, as it
     * ignores all values that are <code>null</code>.
     * 
     * @param values
     * @param column
     * @param value
     */
    public static void putIfNotNull(ContentValues values, String column,
            Object value) {
        if (value == null || values == null) {
            return;
        }
        /*
         * Thanks for not providing a put(String,Object) method to the
         * Map<String,Object>!! :-(
         */
        if (value instanceof Byte) {
            values.put(column, (Byte) value);
        } else if (value instanceof Short) {
            values.put(column, (Short) value);
        } else if (value instanceof Integer) {
            values.put(column, (Integer) value);
        } else if (value instanceof Long) {
            values.put(column, (Long) value);
        } else if (value instanceof Float) {
            values.put(column, (Float) value);
        } else if (value instanceof Double) {
            values.put(column, (Double) value);
        } else if (value instanceof Boolean) {
            values.put(column, (Boolean) value);
        } else if (value instanceof byte[]) {
            values.put(column, (byte[]) value);
        } else if (value instanceof String) {
            values.put(column, (String) value);
        } else {
            // Hope for the best and convert it to a string
            LOG.warn("Column: " + column
                    + "Trying to put non primitive value to ContentValues: "
                    + value + ". Converting to string.");
            values.put(column, value.toString());
        }
    }

    /**
     * Retrieves a {@link Date} value from a cursor.<br/>
     * <b>Note: The database field is supposed to be a <code>INTEGER</code>
     * field.</b>
     * 
     * @param cursor
     *            cursor to retrieve the value from
     * @param index
     *            index of the field within the cursor
     * @return the converted {@link Date} object or <code>null</code> if the
     *         field is <code>null</code>
     */
    public static Date loadDate(Cursor cursor, int index) {
        return DateUtil.toDate(loadLong(cursor, index));
    }

    /**
     * Retrieves a {@link Boolean} value from a cursor.<br/>
     * <b>Note: The database field is supposed to be a <code>INTEGER</code>
     * field.</b>
     * 
     * @param cursor
     *            cursor to retrieve the value from
     * @param index
     *            index of the field within the cursor
     * @return the converted {@link Boolean} object or <code>null</code> if the
     *         field is <code>null</code>
     */
    public static Boolean loadBoolean(Cursor cursor, int index) {
        Integer intValue = loadInteger(cursor, index);
        return toBoolean(intValue);
    }

    //
    // public static Integer storeBoolean() {
    //
    // }

    /**
     * Converts an {@link Integer} to {@link Boolean} according to the following
     * rules:
     * <ul>
     * <li><code>null</code> yields <code>null</code></li>
     * <li>Only <code>0</code> yields {@link Boolean#FALSE}</li>
     * <li>Everything else yields {@link Boolean#TRUE}</li>
     * </ul>
     * 
     * @param intValue
     *            the numeric value to convert
     * @return {@link Boolean} representation of <code>intValue</code>
     */
    public static Boolean toBoolean(Integer intValue) {
        if (intValue == null) {
            return null;
        }
        if (FALSE.equals(intValue)) {
            return Boolean.FALSE;
        }
        return Boolean.TRUE;
    }

    /**
     * Converts a generic {@link HashMap} to android's {@link ContentValues}.
     * 
     * @param input
     *            map whose value should be transformed to {@link ContentValues}
     *            . Can be <code>null</code> .
     * @return an instance of {@link ContentValues} that contains the map's
     *         entries or <code>null</code> if map is <code>null</code>.
     */
    public static ContentValues toContentValues(Map<String, Object> input) {
        if (input == null) {
            return null;
        }
        Parcel parcel = Parcel.obtain();
        parcel.writeMap(input);
        parcel.setDataPosition(0);
        return ContentValues.CREATOR.createFromParcel(parcel);
    }

    /**
     * Converts a {@link Boolean} to {@link Integer} according to the following
     * rules:
     * <ul>
     * <li><code>null</code> yields <code>null</code></li>
     * <li>Only {@link Boolean#FALSE} yields <code>0</code></li>
     * <li>Everything else yields <code>1</code></li>
     * </ul>
     * 
     * @param intValue
     *            the numeric value to convert
     * @return {@link Boolean} representation of <code>intValue</code>
     */
    public static Integer toInteger(Boolean boolValue) {
        if (boolValue == null) {
            return null;
        }
        if (Boolean.FALSE.equals(boolValue)) {
            return FALSE;
        }
        return TRUE;
    }

    /**
     * Retrieves an {@link Integer} value from a cursor. Contrary to
     * {@link Cursor#getInt(int)} this returns <code>null</code> when the field
     * is <code>null</code> in the database..
     * 
     * @param cursor
     *            cursor to retrieve the value from
     * @param index
     *            index of the field within the cursor
     * @return the boxed {@link Integer} value or <code>null</code> if the field
     *         is <code>null</code>
     */
    public static Integer loadInteger(Cursor cursor, int index) {
        if (!cursor.isNull(index)) {
            return cursor.getInt(index);
        }
        return null;
    }

    /**
     * Retrieves a {@link Long} value from a cursor. Contrary to
     * {@link Cursor#getLong(int)} this returns <code>null</code> when the field
     * is <code>null</code> in the database..
     * 
     * @param cursor
     *            cursor to retrieve the value from
     * @param index
     *            index of the field within the cursor
     * @return the boxed {@link Long} value or <code>null</code> if the field is
     *         <code>null</code>
     */
    public static Long loadLong(Cursor cursor, int index) {
        if (!cursor.isNull(index)) {
            return cursor.getLong(index);
        }
        return null;
    }
}