/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.rice.krad.uif.util;
  
  import java.beans.BeanInfo;
  import java.beans.IntrospectionException;
  import java.beans.Introspector;
  import java.beans.PropertyDescriptor;
  import java.beans.PropertyEditorManager;
  import java.lang.reflect.Method;
  import java.util.Collections;
  import java.util.Map;
  import java.util.WeakHashMap;
  
  import org.apache.log4j.Logger;
  
  /**
   * Utility methods to get/set property values and working with objects.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class ObjectPropertyUtils {
  
      private static final Logger LOG = Logger.getLogger(ObjectPropertyUtils.class);
  
      /**
       * Internal property descriptor cache.
       * 
       * <p>
       * NOTE: WeakHashMap is used as the internal cache representation. Since class objects are used
       * as the keys, this allows property descriptors to stay in cache until the class loader is
       * unloaded, but will not prevent the class loader itself from unloading. PropertyDescriptor
       * instances do not hold hard references back to the classes they refer to, so weak value
       * maintenance is not necessary.
       * </p>
       */
      private static Map<Class<?>, Map<String, PropertyDescriptor>> PROPERTY_DESCRIPTOR_CACHE = Collections
              .synchronizedMap(new WeakHashMap<Class<?>, Map<String, PropertyDescriptor>>(2048));
  
      /**
       * Get a mapping of property descriptors by property name for a bean class.
       * 
       * @param beanClass The bean class.
       * @return A mapping of all property descriptors for the bean class, by property name.
       */
      public static Map<String, PropertyDescriptor> getPropertyDescriptors(Class<?> beanClass) {
          Map<String, PropertyDescriptor> propertyDescriptors = PROPERTY_DESCRIPTOR_CACHE.get(beanClass);
  
          if (propertyDescriptors == null) {
              BeanInfo beanInfo;
              try {
                  beanInfo = Introspector.getBeanInfo(beanClass);
              } catch (IntrospectionException e) {
                  LOG.warn(
                          "Bean Info not found for bean " + beanClass, e);
                  beanInfo = null;
              }
  
              Map<String, PropertyDescriptor> unsynchronizedPropertyDescriptorMap = new java.util.LinkedHashMap<String, PropertyDescriptor>();
  
              if (beanInfo != null) {
                  for (PropertyDescriptor propertyDescriptor : beanInfo
                          .getPropertyDescriptors()) {
                      unsynchronizedPropertyDescriptorMap.put(propertyDescriptor.getName(), propertyDescriptor);
                  }
              }
  
              PROPERTY_DESCRIPTOR_CACHE.put(beanClass, propertyDescriptors = Collections.unmodifiableMap(Collections
                      .synchronizedMap(unsynchronizedPropertyDescriptorMap)));
          }
  
          return propertyDescriptors;
      }
  
      /**
       * Get a property descriptor from a class by property name.
       * 
       * @param beanClass The bean class.
       * @param propertyName The bean property name.
       * @return The property descriptor named on the bean class.
       */
      public static PropertyDescriptor getPropertyDescriptor(Class<?> beanClass, String propertyName) {
          if (propertyName == null) {
              throw new IllegalArgumentException("Null property name");
          }
  
         PropertyDescriptor propertyDescriptor = getPropertyDescriptors(beanClass).get(propertyName);
         if (propertyDescriptor != null) {
             return propertyDescriptor;
         } else {
             throw new IllegalArgumentException("Property " + propertyName
                     + " not found for bean " + beanClass);
         }
     }
 
     /**
      * Get the read method for a specific property on a bean class.
      * 
      * @param beanClass The bean class.
      * @param propertyName The property name.
      * @return The read method for the property.
      */
     public static Method getReadMethod(Class<?> beanClass, String propertyName) {
         if (propertyName == null || propertyName.length() == 0) {
             return null;
         }
 
         Method readMethod = null;
 
         PropertyDescriptor propertyDescriptor = ObjectPropertyUtils.getPropertyDescriptors(beanClass).get(propertyName);
         if (propertyDescriptor != null) {
             readMethod = propertyDescriptor.getReadMethod();
         }
 
         if (readMethod == null) {
             try {
                 readMethod = beanClass.getMethod("get" + Character.toUpperCase(propertyName.charAt(0))
                         + propertyName.substring(1));
             } catch (SecurityException e) {
                 // Ignore
             } catch (NoSuchMethodException e) {
                 // Ignore
             }
         }
 
         if (readMethod == null) {
             try {
                 Method trm = beanClass.getMethod("is"
                         + Character.toUpperCase(propertyName.charAt(0))
                         + propertyName.substring(1));
                 if (trm.getReturnType() == Boolean.class
                         || trm.getReturnType() == Boolean.TYPE)
                     readMethod = trm;
             } catch (SecurityException e) {
                 // Ignore
             } catch (NoSuchMethodException e) {
                 // Ignore
             }
         }
 
         return readMethod;
     }
 
     /**
      * Get the read method for a specific property on a bean class.
      * 
      * @param beanClass The bean class.
      * @param propertyName The property name.
      * @return The read method for the property.
      */
     public static Method getWriteMethod(Class<?> beanClass, String propertyName) {
         PropertyDescriptor propertyDescriptor = ObjectPropertyUtils.getPropertyDescriptors(beanClass).get(propertyName);
 
         if (propertyDescriptor != null) {
             Method writeMethod = propertyDescriptor.getWriteMethod();
             assert writeMethod == null
                     || (writeMethod.getParameterTypes().length == 1 && writeMethod.getParameterTypes()[0] != null) : writeMethod;
             return writeMethod;
         } else {
             return null;
         }
     }
 
     /**
      * Copy properties from a string map to an object.
      * 
      * @param properties The string map. The keys of this map must be valid property path
      *        expressions in the context of the target object. The values are the string
      *        representations of the target bean properties.
      * @param object The target object, to copy the property values to.
      * @see ObjectPathExpressionParser
      */
     public static void copyPropertiesToObject(Map<String, String> properties, Object object) {
         for (Map.Entry<String, String> property : properties.entrySet()) {
             setPropertyValue(object, property.getKey(), property.getValue());
         }
     }
 
     /**
      * Get the type of a bean property.
      * 
      * @param beanClass The bean class.
      * @param propertyPath A valid property path expression in the context of the bean class.
      * @return The property type referred to by the provided bean class and property path.
      * @see ObjectPathExpressionParser
      */
     public static Class<?> getPropertyType(Class<?> beanClass, String propertyPath) {
         return ObjectPropertyReference.resolvePath(null, beanClass, propertyPath, false).getPropertyType();
     }
 
     /**
      * Get the type of a bean property.
      * 
      * @param object The bean instance. Use {@link #getPropertyType(Class, String)} to look up
      *        property types when an instance is not available.
      * @param propertyPath A valid property path expression in the context of the bean.
      * @return The property type referred to by the provided bean and property path.
      * @see ObjectPathExpressionParser
      */
     public static Class<?> getPropertyType(Object object, String propertyPath) {
         return ObjectPropertyReference.resolvePath(object, object.getClass(), propertyPath, false).getPropertyType();
     }
 
     /**
      * Look up a property value.
      * 
      * @param object The bean instance to look up a property value for.
      * @param propertyPath A valid property path expression in the context of the bean.
      * @return The value of the property referred to by the provided bean and property path.
      * @see ObjectPathExpressionParser
      */
     @SuppressWarnings("unchecked")
     public static <T extends Object> T getPropertyValue(Object object, String propertyPath) {
         if (ProcessLogger.isTraceActive() && object != null) {
             // May be uncommented for debugging high execution count
             // ProcessLogger.ntrace(object.getClass().getSimpleName() + ":r:" + propertyPath, "", 1000);
             ProcessLogger.countBegin("bean-property-read");
         }
 
         try {
         
             return (T) ObjectPropertyReference.resolvePath(object, object.getClass(), propertyPath, false).get();
         
         } catch (RuntimeException e) {
             throw new RuntimeException("Error getting property '" + propertyPath + "' from " + object, e);
         } finally {
             if (ProcessLogger.isTraceActive() && object != null) {
                 ProcessLogger.countEnd("bean-property-read", object.getClass().getSimpleName() + ":" + propertyPath);
             }
         }
         
     }
 
     /**
      * Initialize a property value.
      * 
      * <p>
      * Upon returning from this method, the property referred to by the provided bean and property
      * path will have been initialized with a default instance of the indicated property type.
      * </p>
      * 
      * @param object The bean instance to initialize a property value for.
      * @param propertyPath A valid property path expression in the context of the bean.
      * @see #getPropertyType(Object, String)
      * @see #setPropertyValue(Object, String, Object)
      * @see ObjectPathExpressionParser
      */
     public static void initializeProperty(Object object, String propertyPath) {
         Class<?> propertyType = getPropertyType(object, propertyPath);
         try {
             setPropertyValue(object, propertyPath, propertyType.newInstance());
         } catch (InstantiationException e) {
             // just set the value to null
             setPropertyValue(object, propertyPath, null);
         } catch (IllegalAccessException e) {
             throw new RuntimeException("Unable to set new instance for property: " + propertyPath, e);
         }
     }
 
     /**
      * Modify a property value.
      * 
      * <p>
      * Upon returning from this method, the property referred to by the provided bean and property
      * path will have been populated with property value provided. If the propertyValue does not
      * match the type of the indicated property, then type conversion will be attempted using
      * {@link PropertyEditorManager}.
      * </p>
      * 
      * @param object The bean instance to initialize a property value for.
      * @param propertyPath A valid property path expression in the context of the bean.
      * @param propertyValue The value to populate value in the property referred to by the provided
      *        bean and property path.
      * @see ObjectPathExpressionParser
      * @throws RuntimeException If the property path is not valid in the context of the bean
      *         provided.
      */
     public static void setPropertyValue(Object object, String propertyPath, Object propertyValue) {
         if (ProcessLogger.isTraceActive() && object != null) {
             // May be uncommented for debugging high execution count
             // ProcessLogger.ntrace(object.getClass().getSimpleName() + ":w:" + propertyPath + ":", "", 1000);
             ProcessLogger.countBegin("bean-property-write");
         }
         
         try {
 
             ObjectPropertyReference.resolvePath(object, object.getClass(), propertyPath, true).set(propertyValue);
         
         } catch (RuntimeException e) {
             throw new RuntimeException("Error setting property '" + propertyPath + "' on " + object + " with "
                     + propertyValue, e);
         } finally {
             if (ProcessLogger.isTraceActive() && object != null) {
                 ProcessLogger.countEnd("bean-property-write", object.getClass().getSimpleName() + ":" + propertyPath);
             }
         }
         
     }
 
     /**
      * Modify a property value.
      * 
      * <p>
      * Upon returning from this method, the property referred to by the provided bean and property
      * path will have been populated with property value provided. If the propertyValue does not
      * match the type of the indicated property, then type conversion will be attempted using
      * {@link PropertyEditorManager}.
      * </p>
      * 
      * @param object The bean instance to initialize a property value for.
      * @param propertyPath A property path expression in the context of the bean.
      * @param propertyValue The value to populate value in the property referred to by the provided
      *        bean and property path.
      * @param ignore True if invalid property values should be ignored, false to throw a
      *        RuntimeException if the property refernce is invalid.
      * @see ObjectPathExpressionParser
      */
     public static void setPropertyValue(Object object, String propertyPath, Object propertyValue, boolean ignoreUnknown) {
         try {
             setPropertyValue(object, propertyPath, propertyValue);
         } catch (RuntimeException e) {
             // only throw exception if they have indicated to not ignore unknown
             if (!ignoreUnknown) {
                 throw e;
             }
             if (LOG.isTraceEnabled()) {
                 LOG.trace("Ignoring exception thrown during setting of property '" + propertyPath + "': "
                         + e.getLocalizedMessage());
             }
         }
     }
 
     /**
      * Determine if a property is readable.
      * 
      * @param object The bean instance to initialize a property value for.
      * @param propertyPath A property path expression in the context of the bean.
      * @return True if the path expression resolves to a valid readable property reference in the
      *         context of the bean provided.
      */
     public static boolean isReadableProperty(Object object, String propertyPath) {
         return ObjectPropertyReference.resolvePath(object, object.getClass(), propertyPath, false).canRead();
     }
 
     /**
      * Determine if a property is writable.
      * 
      * @param object The bean instance to initialize a property value for.
      * @param propertyPath A property path expression in the context of the bean.
      * @return True if the path expression resolves to a valid writable property reference in the
      *         context of the bean provided.
      */
     public static boolean isWritableProperty(Object object, String propertyPath) {
         return ObjectPropertyReference.resolvePath(object, object.getClass(), propertyPath, false).canWrite();
     }
 
     /**
      * Private constructor - utility class only.
      */
     private ObjectPropertyUtils() {}
 
 }