1 /*
2 * #%L
3 * settings4j
4 * ===============================================================
5 * Copyright (C) 2008 - 2015 Brabenetz Harald, Austria
6 * ===============================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * #L%
19 */
20 package org.settings4j.connector;
21
22 import java.util.Locale;
23
24 /**
25 * The Environment variable implementation of an {@link org.settings4j.Connector}.
26 * <p>
27 * see also {@link System#getenv(String)}.
28 * </p>
29 *
30 * @author Harald.Brabenetz
31 */
32 public class EnvironmentConnector extends AbstractPropertyConnector {
33
34 /** General Logger for this Class. */
35 private static final org.slf4j.Logger LOG = org.slf4j.LoggerFactory.getLogger(EnvironmentConnector.class);
36
37 /**
38 * Very similar to <code>System.getenv</code> except that the {@link SecurityException} is hidden.
39 *
40 * @param key The key to search for.
41 * @return the string value of the Environment variable, or the default value if there is no property with that key.
42 */
43 @Override
44 public String getString(final String key) {
45 final String value = getEnv(key);
46 if (value == null) {
47 final String uppercaseKey = key.toUpperCase(Locale.ENGLISH).replaceAll("\\W", "_");
48 LOG.debug("Try to find value for KEY: {}", uppercaseKey);
49 return getEnv(uppercaseKey);
50 }
51 return value;
52 }
53
54 private String getEnv(final String key) {
55 try {
56 return System.getenv(key);
57 } catch (final SecurityException e) {
58 LOG.info("Was not allowed to read environment value for key '{}'.", key, e);
59 return null;
60 } catch (final Throwable e) {
61 LOG.warn("Exception reading environment value for key '{}': {}", key, e.getMessage());
62 return null;
63 }
64 }
65 }