Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.rave.util; import org.apache.commons.lang3.StringUtils; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer; import org.springframework.core.io.ClassPathResource; import org.springframework.core.io.FileSystemResource; import org.springframework.core.io.Resource; import java.util.Collections; import java.util.HashMap; import java.util.Map; import java.util.Properties; /** * Reads property from the default location unless a system property is set. * The name of the system property is set by the parameter {@literal systemPropertyName}. */ public class OverridablePropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer { private static final String CLASSPATH = "classpath:"; private String systemPropertyName; private Map<String, String> resolvedProps; @Override public void setLocation(Resource location) { if (StringUtils.isBlank(getSystemPropertyName())) { throw new IllegalArgumentException("Missing value for 'systemPropertyName'."); } Resource locationResource; final String overrideProperty = System.getProperty(getSystemPropertyName()); if (StringUtils.isBlank(overrideProperty)) { locationResource = location; } else if (overrideProperty.startsWith(CLASSPATH)) { locationResource = new ClassPathResource(overrideProperty.substring(CLASSPATH.length())); } else { locationResource = new FileSystemResource(overrideProperty); } super.setLocation(locationResource); } @Override protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props) throws BeansException { super.processProperties(beanFactoryToProcess, props); // load the application properties into a map that is exposed via public getter resolvedProps = new HashMap<String, String>(); for (Object key : props.keySet()) { String keyStr = key.toString(); resolvedProps.put(keyStr, resolvePlaceholder(keyStr, props, SYSTEM_PROPERTIES_MODE_OVERRIDE)); } } public void setSystemPropertyName(String systemPropertyName) { this.systemPropertyName = systemPropertyName; } public String getSystemPropertyName() { return systemPropertyName; } public Map<String, String> getResolvedProps() { return Collections.unmodifiableMap(resolvedProps); } }