import java.util.Properties;

import java.util.Set;

import org.apache.catalina.Lifecycle;

import org.apache.catalina.LifecycleEvent;

import org.apache.catalina.LifecycleListener;

    public static class SystemPropertyReplacementListener

            implements LifecycleListener {

        protected Log log = LogFactory.getLog(Digester.class);

        protected StringManager sm = StringManager.getManager(Digester.class);

        @Override

        public void lifecycleEvent(LifecycleEvent event) {

            if (propertySource != null && Lifecycle.BEFORE_INIT_EVENT.equals(event.getType())) {

                IntrospectionUtils.PropertySource[] propertySources =

                        new IntrospectionUtils.PropertySource[] { propertySource };

                Properties properties = System.getProperties();

                Set<String> names = properties.stringPropertyNames();

                for (String name : names) {

                    String value = System.getProperty(name);

                    if (value != null) {

                        try {

                            String newValue = IntrospectionUtils.replaceProperties(value, null, propertySources);

                            if (value != newValue) {

                                System.setProperty(name, newValue);

                            }

                        } catch (Exception e) {

                            log.warn(sm.getString("digester.failedToUpdateSystemProperty", name, value), e);

                        }

                    }

                }

            }

        }

    }

      <p>Property replacement from the specified property source on the JVM

         system properties can also be done by adding the

         <code>org.apache.tomcat.util.digester.Digester$SystemPropertyReplacementListener</code>

         listener as a Server listener in the container.</p>

digester.failedToUpdateSystemProperty=System property [{0}] failed to update and remains [{1}]