/**
    *    Copyright 2009-2015 the original author or authors.
    *
    *    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.ibatis.reflection;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Field;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.lang.reflect.ReflectPermission;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.ibatis.reflection.invoker.GetFieldInvoker;
  import org.apache.ibatis.reflection.invoker.Invoker;
  import org.apache.ibatis.reflection.invoker.MethodInvoker;
  import org.apache.ibatis.reflection.invoker.SetFieldInvoker;
  import org.apache.ibatis.reflection.property.PropertyNamer;
  
  /*
   * This class represents a cached set of class definition information that
   * allows for easy mapping between property names and getter/setter methods.
   */
  /**
   * @author Clinton Begin
   */
  public class Reflector {
  
    private static final String[] EMPTY_STRING_ARRAY = new String[0];
  
    private Class<?> type;
    private String[] readablePropertyNames = EMPTY_STRING_ARRAY;
    private String[] writeablePropertyNames = EMPTY_STRING_ARRAY;
    private Map<String, Invoker> setMethods = new HashMap<String, Invoker>();
    private Map<String, Invoker> getMethods = new HashMap<String, Invoker>();
    private Map<String, Class<?>> setTypes = new HashMap<String, Class<?>>();
    private Map<String, Class<?>> getTypes = new HashMap<String, Class<?>>();
    private Constructor<?> defaultConstructor;
  
    private Map<String, String> caseInsensitivePropertyMap = new HashMap<String, String>();
  
    public Reflector(Class<?> clazz) {
      type = clazz;
      addDefaultConstructor(clazz);
      addGetMethods(clazz);
      addSetMethods(clazz);
      addFields(clazz);
      readablePropertyNames = getMethods.keySet().toArray(new String[getMethods.keySet().size()]);
      writeablePropertyNames = setMethods.keySet().toArray(new String[setMethods.keySet().size()]);
      for (String propName : readablePropertyNames) {
        caseInsensitivePropertyMap.put(propName.toUpperCase(Locale.ENGLISH), propName);
      }
      for (String propName : writeablePropertyNames) {
        caseInsensitivePropertyMap.put(propName.toUpperCase(Locale.ENGLISH), propName);
      }
    }
  
    private void addDefaultConstructor(Class<?> clazz) {
      Constructor<?>[] consts = clazz.getDeclaredConstructors();
      for (Constructor<?> constructor : consts) {
        if (constructor.getParameterTypes().length == 0) {
          if (canAccessPrivateMethods()) {
            try {
              constructor.setAccessible(true);
            } catch (Exception e) {
              // Ignored. This is only a final precaution, nothing we can do.
            }
          }
          if (constructor.isAccessible()) {
            this.defaultConstructor = constructor;
          }
        }
      }
    }
  
    private void addGetMethods(Class<?> cls) {
      Map<String, List<Method>> conflictingGetters = new HashMap<String, List<Method>>();
      Method[] methods = getClassMethods(cls);
      for (Method method : methods) {
        String name = method.getName();
        if (name.startsWith("get") && name.length() > 3) {
          if (method.getParameterTypes().length == 0) {
           name = PropertyNamer.methodToProperty(name);
           addMethodConflict(conflictingGetters, name, method);
         }
       } else if (name.startsWith("is") && name.length() > 2) {
         if (method.getParameterTypes().length == 0) {
           name = PropertyNamer.methodToProperty(name);
           addMethodConflict(conflictingGetters, name, method);
         }
       }
     }
     resolveGetterConflicts(conflictingGetters);
   }
 
   private void resolveGetterConflicts(Map<String, List<Method>> conflictingGetters) {
     for (String propName : conflictingGetters.keySet()) {
       List<Method> getters = conflictingGetters.get(propName);
       Iterator<Method> iterator = getters.iterator();
       Method firstMethod = iterator.next();
       if (getters.size() == 1) {
         addGetMethod(propName, firstMethod);
       } else {
         Method getter = firstMethod;
         Class<?> getterType = firstMethod.getReturnType();
         while (iterator.hasNext()) {
           Method method = iterator.next();
           Class<?> methodType = method.getReturnType();
           if (methodType.equals(getterType)) {
             throw new ReflectionException("Illegal overloaded getter method with ambiguous type for property "
                 + propName + " in class " + firstMethod.getDeclaringClass()
                 + ".  This breaks the JavaBeans " + "specification and can cause unpredicatble results.");
           } else if (methodType.isAssignableFrom(getterType)) {
             // OK getter type is descendant
           } else if (getterType.isAssignableFrom(methodType)) {
             getter = method;
             getterType = methodType;
           } else {
             throw new ReflectionException("Illegal overloaded getter method with ambiguous type for property "
                 + propName + " in class " + firstMethod.getDeclaringClass()
                 + ".  This breaks the JavaBeans " + "specification and can cause unpredicatble results.");
           }
         }
         addGetMethod(propName, getter);
       }
     }
   }
 
   private void addGetMethod(String name, Method method) {
     if (isValidPropertyName(name)) {
       getMethods.put(name, new MethodInvoker(method));
       getTypes.put(name, method.getReturnType());
     }
   }
 
   private void addSetMethods(Class<?> cls) {
     Map<String, List<Method>> conflictingSetters = new HashMap<String, List<Method>>();
     Method[] methods = getClassMethods(cls);
     for (Method method : methods) {
       String name = method.getName();
       if (name.startsWith("set") && name.length() > 3) {
         if (method.getParameterTypes().length == 1) {
           name = PropertyNamer.methodToProperty(name);
           addMethodConflict(conflictingSetters, name, method);
         }
       }
     }
     resolveSetterConflicts(conflictingSetters);
   }
 
   private void addMethodConflict(Map<String, List<Method>> conflictingMethods, String name, Method method) {
     List<Method> list = conflictingMethods.get(name);
     if (list == null) {
       list = new ArrayList<Method>();
       conflictingMethods.put(name, list);
     }
     list.add(method);
   }
 
   private void resolveSetterConflicts(Map<String, List<Method>> conflictingSetters) {
     for (String propName : conflictingSetters.keySet()) {
       List<Method> setters = conflictingSetters.get(propName);
       Method firstMethod = setters.get(0);
       if (setters.size() == 1) {
         addSetMethod(propName, firstMethod);
       } else {
         Class<?> expectedType = getTypes.get(propName);
         if (expectedType == null) {
           throw new ReflectionException("Illegal overloaded setter method with ambiguous type for property "
               + propName + " in class " + firstMethod.getDeclaringClass() + ".  This breaks the JavaBeans " +
               "specification and can cause unpredicatble results.");
         } else {
           Iterator<Method> methods = setters.iterator();
           Method setter = null;
           while (methods.hasNext()) {
             Method method = methods.next();
             if (method.getParameterTypes().length == 1
                 && expectedType.equals(method.getParameterTypes()[0])) {
               setter = method;
               break;
             }
           }
           if (setter == null) {
             throw new ReflectionException("Illegal overloaded setter method with ambiguous type for property "
                 + propName + " in class " + firstMethod.getDeclaringClass() + ".  This breaks the JavaBeans " +
                 "specification and can cause unpredicatble results.");
           }
           addSetMethod(propName, setter);
         }
       }
     }
   }
 
   private void addSetMethod(String name, Method method) {
     if (isValidPropertyName(name)) {
       setMethods.put(name, new MethodInvoker(method));
       setTypes.put(name, method.getParameterTypes()[0]);
     }
   }
 
   private void addFields(Class<?> clazz) {
     Field[] fields = clazz.getDeclaredFields();
     for (Field field : fields) {
       if (canAccessPrivateMethods()) {
         try {
           field.setAccessible(true);
         } catch (Exception e) {
           // Ignored. This is only a final precaution, nothing we can do.
         }
       }
       if (field.isAccessible()) {
         if (!setMethods.containsKey(field.getName())) {
           // issue #379 - removed the check for final because JDK 1.5 allows
           // modification of final fields through reflection (JSR-133). (JGB)
           // pr #16 - final static can only be set by the classloader
           int modifiers = field.getModifiers();
           if (!(Modifier.isFinal(modifiers) && Modifier.isStatic(modifiers))) {
             addSetField(field);
           }
         }
         if (!getMethods.containsKey(field.getName())) {
           addGetField(field);
         }
       }
     }
     if (clazz.getSuperclass() != null) {
       addFields(clazz.getSuperclass());
     }
   }
 
   private void addSetField(Field field) {
     if (isValidPropertyName(field.getName())) {
       setMethods.put(field.getName(), new SetFieldInvoker(field));
       setTypes.put(field.getName(), field.getType());
     }
   }
 
   private void addGetField(Field field) {
     if (isValidPropertyName(field.getName())) {
       getMethods.put(field.getName(), new GetFieldInvoker(field));
       getTypes.put(field.getName(), field.getType());
     }
   }
 
   private boolean isValidPropertyName(String name) {
     return !(name.startsWith("$") || "serialVersionUID".equals(name) || "class".equals(name));
   }
 
   /*
    * This method returns an array containing all methods
    * declared in this class and any superclass.
    * We use this method, instead of the simpler Class.getMethods(),
    * because we want to look for private methods as well.
    *
    * @param cls The class
    * @return An array containing all methods in this class
    */
   private Method[] getClassMethods(Class<?> cls) {
     Map<String, Method> uniqueMethods = new HashMap<String, Method>();
     Class<?> currentClass = cls;
     while (currentClass != null) {
       addUniqueMethods(uniqueMethods, currentClass.getDeclaredMethods());
 
       // we also need to look for interface methods -
       // because the class may be abstract
       Class<?>[] interfaces = currentClass.getInterfaces();
       for (Class<?> anInterface : interfaces) {
         addUniqueMethods(uniqueMethods, anInterface.getMethods());
       }
 
       currentClass = currentClass.getSuperclass();
     }
 
     Collection<Method> methods = uniqueMethods.values();
 
     return methods.toArray(new Method[methods.size()]);
   }
 
   private void addUniqueMethods(Map<String, Method> uniqueMethods, Method[] methods) {
     for (Method currentMethod : methods) {
       if (!currentMethod.isBridge()) {
         String signature = getSignature(currentMethod);
         // check to see if the method is already known
         // if it is known, then an extended class must have
         // overridden a method
         if (!uniqueMethods.containsKey(signature)) {
           if (canAccessPrivateMethods()) {
             try {
               currentMethod.setAccessible(true);
             } catch (Exception e) {
               // Ignored. This is only a final precaution, nothing we can do.
             }
           }
 
           uniqueMethods.put(signature, currentMethod);
         }
       }
     }
   }
 
   private String getSignature(Method method) {
     StringBuilder sb = new StringBuilder();
     Class<?> returnType = method.getReturnType();
     if (returnType != null) {
       sb.append(returnType.getName()).append('#');
     }
     sb.append(method.getName());
     Class<?>[] parameters = method.getParameterTypes();
     for (int i = 0; i < parameters.length; i++) {
       if (i == 0) {
         sb.append(':');
       } else {
         sb.append(',');
       }
       sb.append(parameters[i].getName());
     }
     return sb.toString();
   }
 
   private static boolean canAccessPrivateMethods() {
     try {
       SecurityManager securityManager = System.getSecurityManager();
       if (null != securityManager) {
         securityManager.checkPermission(new ReflectPermission("suppressAccessChecks"));
       }
     } catch (SecurityException e) {
       return false;
     }
     return true;
   }
 
   /*
    * Gets the name of the class the instance provides information for
    *
    * @return The class name
    */
   public Class<?> getType() {
     return type;
   }
 
   public Constructor<?> getDefaultConstructor() {
     if (defaultConstructor != null) {
       return defaultConstructor;
     } else {
       throw new ReflectionException("There is no default constructor for " + type);
     }
   }
 
   public boolean hasDefaultConstructor() {
     return defaultConstructor != null;
   }
 
   public Invoker getSetInvoker(String propertyName) {
     Invoker method = setMethods.get(propertyName);
     if (method == null) {
       throw new ReflectionException("There is no setter for property named '" + propertyName + "' in '" + type + "'");
     }
     return method;
   }
 
   public Invoker getGetInvoker(String propertyName) {
     Invoker method = getMethods.get(propertyName);
     if (method == null) {
       throw new ReflectionException("There is no getter for property named '" + propertyName + "' in '" + type + "'");
     }
     return method;
   }
 
   /*
    * Gets the type for a property setter
    *
    * @param propertyName - the name of the property
    * @return The Class of the propery setter
    */
   public Class<?> getSetterType(String propertyName) {
     Class<?> clazz = setTypes.get(propertyName);
     if (clazz == null) {
       throw new ReflectionException("There is no setter for property named '" + propertyName + "' in '" + type + "'");
     }
     return clazz;
   }
 
   /*
    * Gets the type for a property getter
    *
    * @param propertyName - the name of the property
    * @return The Class of the propery getter
    */
   public Class<?> getGetterType(String propertyName) {
     Class<?> clazz = getTypes.get(propertyName);
     if (clazz == null) {
       throw new ReflectionException("There is no getter for property named '" + propertyName + "' in '" + type + "'");
     }
     return clazz;
   }
 
   /*
    * Gets an array of the readable properties for an object
    *
    * @return The array
    */
   public String[] getGetablePropertyNames() {
     return readablePropertyNames;
   }
 
   /*
    * Gets an array of the writeable properties for an object
    *
    * @return The array
    */
   public String[] getSetablePropertyNames() {
     return writeablePropertyNames;
   }
 
   /*
    * Check to see if a class has a writeable property by name
    *
    * @param propertyName - the name of the property to check
    * @return True if the object has a writeable property by the name
    */
   public boolean hasSetter(String propertyName) {
     return setMethods.keySet().contains(propertyName);
   }
 
   /*
    * Check to see if a class has a readable property by name
    *
    * @param propertyName - the name of the property to check
    * @return True if the object has a readable property by the name
    */
   public boolean hasGetter(String propertyName) {
     return getMethods.keySet().contains(propertyName);
   }
 
   public String findPropertyName(String name) {
     return caseInsensitivePropertyMap.get(name.toUpperCase(Locale.ENGLISH));
   }
 }