/*
* -----------------------------------------------------------------------\
* PerfCake
*
* Copyright (C) 2010 - 2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* -----------------------------------------------------------------------/
*/
package org.perfcake.util.properties;
/**
* Provides system properties.
*
* @author <a href="mailto:pavel.macik@gmail.com">Pavel Macík</a>
* @author <a href="mailto:marvenec@gmail.com">Martin Večeřa</a>
*/
public enum SystemPropertyGetter implements PropertyGetter {
INSTANCE;
private SystemPropertyGetter() {
}
/**
* Returns a property value.
* First it checks whether a namespace of 'env.' or 'props.' was given as a property name prefix. If so, the property must be taken from these,
* otherwise the default value is returned.
* Second (as no namespace is specified) it looks at system properties using {@link System#getProperty(String)},
* if the system property does not exist
* it looks at environment variables using {@link System#getenv(String)}. If
* the variable does not exist the method returns <code>defautValue</code>.
*
* @param name
* Property name
* @param defaultValue
* Default property value
* @return Property value or <code>defaultValue</code>.
*/
@Override
public String getProperty(final String name, final String defaultValue) {
// first find out whether we specified a namespace
if (name != null) {
if (name.startsWith("env.")) {
final String val = System.getenv(name.substring(4));
if (val != null) {
return val;
} else {
return defaultValue;
}
} else if (name.startsWith("props.")) {
final String val = System.getProperty(name.substring(6));
if (val != null) {
return val;
} else {
return defaultValue;
}
}
// try to find anywhere
if (System.getProperty(name) != null) {
return System.getProperty(name);
} else if (System.getenv(name) != null) {
return System.getenv(name);
}
}
return defaultValue;
}
@Override
public String getProperty(final String propName) {
return getProperty(propName, null);
}
}