examples/simple-singleton/src/main/java/org/superbiz/registry/PropertyRegistry.java

/**
 * 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.superbiz.registry;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.ejb.ConcurrencyManagement;
import javax.ejb.Singleton;
import javax.ejb.Startup;
import java.util.Properties;

import static javax.ejb.ConcurrencyManagementType.BEAN;

@Singleton
@Startup
@ConcurrencyManagement(BEAN)
public class PropertyRegistry {

    // Note the java.util.Properties object is a thread-safe
    // collections that uses synchronization.  If it didn't
    // you would have to use some form of synchronization
    // to ensure the PropertyRegistryBean is thread-safe.
    private final Properties properties = new Properties();

    // The @Startup annotation ensures that this method is
    // called when the application starts up.
    @PostConstruct
    public void applicationStartup() {
        properties.putAll(System.getProperties());
    }

    @PreDestroy
    public void applicationShutdown() {
        properties.clear();
    }

    public String getProperty(final String key) {
        return properties.getProperty(key);
    }

    public String setProperty(final String key, final String value) {
        return (String) properties.setProperty(key, value);
    }

    public String removeProperty(final String key) {
        return (String) properties.remove(key);
    }
}