/* * Copyright 1999-2005 The Apache Software Foundation. *  * 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.apache.log4j.config;import java.beans.*;import java.lang.reflect.*;import org.apache.log4j.Priority;import org.apache.log4j.helpers.LogLog;/**   Used for inferring configuration information for a log4j's component.   @author  Anders Kristensen */public class PropertyGetter {  protected static final Object[] NULL_ARG = new Object[] {};  protected Object obj;  protected PropertyDescriptor[] props;  public interface PropertyCallback {    void foundProperty(Object obj, String prefix, String name, Object value);  }  /**    Create a new PropertyGetter for the specified Object. This is done    in prepartion for invoking {@link    #getProperties(PropertyGetter.PropertyCallback, String)} one or    more times.    @param obj the object for which to set properties */  public  PropertyGetter(Object obj) throws IntrospectionException {    BeanInfo bi = Introspector.getBeanInfo(obj.getClass());    props = bi.getPropertyDescriptors();    this.obj = obj;  }  public  static  void getProperties(Object obj, PropertyCallback callback, String prefix) {    try {      new PropertyGetter(obj).getProperties(callback, prefix);    } catch (IntrospectionException ex) {      LogLog.error("Failed to introspect object " + obj, ex);    }  }  public  void getProperties(PropertyCallback callback, String prefix) {    for (int i = 0; i < props.length; i++) {      Method getter = props[i].getReadMethod();      if (getter == null) continue;      if (!isHandledType(getter.getReturnType())) {	//System.err.println("Ignoring " + props[i].getName() +" " + getter.getReturnType());	continue;      }      String name = props[i].getName();      try {	Object result = getter.invoke(obj, NULL_ARG);	//System.err.println("PROP " + name +": " + result);	if (result != null) {	  callback.foundProperty(obj, prefix, name, result);	}      } catch (Exception ex) {	LogLog.warn("Failed to get value of property " + name);      }    }  }  protected  boolean isHandledType(Class type) {    return String.class.isAssignableFrom(type) ||      Integer.TYPE.isAssignableFrom(type) ||      Long.TYPE.isAssignableFrom(type)    ||      Boolean.TYPE.isAssignableFrom(type) ||      Priority.class.isAssignableFrom(type);  }}