001 /*
002 * Cumulus4j - Securing your data in the cloud - http://cumulus4j.org
003 * Copyright (C) 2011 NightLabs Consulting GmbH
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program. If not, see <http://www.gnu.org/licenses/>.
017 */
018 package org.cumulus4j.store.resource;
019
020 import java.io.IOException;
021 import java.io.InputStream;
022 import java.util.HashMap;
023 import java.util.Locale;
024 import java.util.Map;
025 import java.util.Properties;
026
027 import javax.jdo.PersistenceManagerFactory;
028
029 /**
030 * Helper class to load resources.
031 *
032 * @author Marco หงุ่ยตระกูล-Schulze - marco at nightlabs dot de
033 */
034 public class ResourceHelper
035 {
036 /**
037 * File name of the backend-properties.
038 * @see #getCumulus4jBackendProperties()
039 */
040 protected static final String CUMULUS4J_BACKEND_PROPERTIES = "cumulus4j-backend.properties";
041
042 /**
043 * <p>
044 * Open an {@link InputStream} reading the file {@value #CUMULUS4J_BACKEND_PROPERTIES}.
045 * </p>
046 * <p>
047 * <b>Important:</b> You must close this <code>InputStream</code>!!!
048 * </p>
049 * @return an {@link InputStream} (never <code>null</code>).
050 * @see #getCumulus4jBackendProperties()
051 */
052 protected static InputStream openCumulus4jBackendProperties()
053 {
054 InputStream in = ResourceHelper.class.getResourceAsStream(CUMULUS4J_BACKEND_PROPERTIES);
055 if (in == null)
056 throw new IllegalStateException("Resource does not exist (or cannot be openend): " + CUMULUS4J_BACKEND_PROPERTIES);
057
058 return in;
059 }
060
061 /**
062 * <p>
063 * Get the backend-properties (from file {@value #CUMULUS4J_BACKEND_PROPERTIES}).
064 * </p>
065 * <p>
066 * The backend-properties are loaded from the file {@value #CUMULUS4J_BACKEND_PROPERTIES}
067 * and used for the configuration of the backend-{@link PersistenceManagerFactory}. This file only
068 * contains connection-independent settings (i.e. things that should never change).
069 * The connection-dependent settings are copied from the frontend-PMF's configuration.
070 * </p>
071 * <p>
072 * Additionally, all properties in the frontend-PMF's configuration starting with
073 * "cumulus4j.datanucleus." or "cumulus4j.javax." are forwarded to the backend-PMF
074 * (without the "cumulus4j."-prefix, of course) <b>overriding</b> the default settings.
075 * </p>
076 * @return a {@link Map} containing all settings from the backend-properties; never <code>null</code>.
077 */
078 public static Map<String, Object> getCumulus4jBackendProperties()
079 {
080 Properties properties = new Properties();
081 try {
082 InputStream in = openCumulus4jBackendProperties();
083 properties.load(in);
084 in.close();
085 } catch (IOException e) { // should never happen as it is a resource => rethrow as RuntimeException
086 throw new RuntimeException(e);
087 }
088
089 Map<String, Object> result = new HashMap<String, Object>(properties.size());
090 for (Map.Entry<?, ?> me : properties.entrySet())
091 result.put(String.valueOf(me.getKey()).toLowerCase(Locale.ENGLISH), String.valueOf(me.getValue()));
092
093 return result;
094 }
095 }