Java tutorial
/* * Copyright 2015 JBoss Inc * * 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 io.apiman.common.config; import java.util.HashSet; import java.util.Iterator; import java.util.Set; import org.apache.commons.configuration.AbstractConfiguration; import org.apache.commons.configuration.SystemConfiguration; /** * A {@link Configuration} implementation based on the current java system * properties. This implementation differs from {@link SystemConfiguration} * because it pulls the system properties live, rather than caching them * when the configuration instance is created. This allows configuration to * change by modifying the system properties at runtime. * * @author eric.wittmann@redhat.com */ public class SystemPropertiesConfiguration extends AbstractConfiguration { /** * Constructor. */ public SystemPropertiesConfiguration() { } /** * @see org.apache.commons.configuration.Configuration#isEmpty() */ @Override public boolean isEmpty() { return false; } /** * @see org.apache.commons.configuration.Configuration#containsKey(java.lang.String) */ @Override public boolean containsKey(String key) { return System.getProperties().containsKey(key); } /** * @see org.apache.commons.configuration.Configuration#getProperty(java.lang.String) */ @Override public Object getProperty(String key) { return System.getProperties().getProperty(key); } /** * @see org.apache.commons.configuration.Configuration#getKeys() */ @Override public Iterator<String> getKeys() { Set<String> keys = new HashSet<>(); Set<Object> keySet = System.getProperties().keySet(); for (Object object : keySet) { keys.add(String.valueOf(object)); } return keys.iterator(); } /** * @see org.apache.commons.configuration.AbstractConfiguration#addPropertyDirect(java.lang.String, java.lang.Object) */ @Override protected void addPropertyDirect(String key, Object value) { System.getProperties().setProperty(key, String.valueOf(value)); } }