1 /* ***************************************************************************
2 * Copyright (c) 2008 Brabenetz Harald, Austria.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 *****************************************************************************/
17 package org.settings4j.connector;
18
19 /**
20 * The Environment variable implementation of an {@link org.settings4j.Connector}.
21 * <p>
22 *
23 * see also {@link System#getenv(String)}.
24 *
25 * @author Harald.Brabenetz
26 *
27 */
28 public class EnvironmentConnector extends AbstractPropertyConnector {
29
30 /** General Logger for this Class. */
31 private static final org.slf4j.Logger LOG = org.slf4j.LoggerFactory.getLogger(EnvironmentConnector.class);
32
33 /**
34 * Very similar to <code>System.getenv</code> except that the {@link SecurityException} is hidden.
35 *
36 * @param key The key to search for.
37 * @param def The default value to return.
38 * @return the string value of the Environment variable, or the default value if there is no property with that key.
39 */
40 @Override
41 protected String getProperty(final String key, final String def) {
42 try {
43 final String envValue = System.getenv(key);
44 if (envValue == null) {
45 return def;
46 }
47 return envValue;
48 } catch (final SecurityException e) {
49 LOG.info("Was not allowed to read environment value for key '{}'.", key);
50 return def;
51 } catch (final Throwable e) {
52 LOG.warn("Exception reading environment value for key '{}': {}", key, e.getMessage());
53 return def;
54 }
55 }
56 }