/*
    * 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.apache.commons.lang3.reflect;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.util.Objects;
  
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.lang3.ClassUtils;
  
  /**
   *  Utility reflection methods focused on constructors, modeled after
   * {@link MethodUtils}.
   *
   * <h2>Known Limitations</h2>
   * <h3>Accessing Public Constructors In A Default Access Superclass</h3>
   * <p>There is an issue when invoking {@code public} constructors
   * contained in a default access superclass. Reflection correctly locates these
   * constructors and assigns them as {@code public}. However, an
   * {@link IllegalAccessException} is thrown if the constructor is
   * invoked.</p>
   *
   * <p>{@link ConstructorUtils} contains a workaround for this situation: it
   * will attempt to call {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} on this constructor. If this
   * call succeeds, then the method can be invoked as normal. This call will only
   * succeed when the application has sufficient security privileges. If this call
   * fails then a warning will be logged and the method may fail.</p>
   *
   * @since 2.5
   */
  public class ConstructorUtils {
  
      /**
       * Finds a constructor given a class and signature, checking accessibility.
       *
       * <p>This finds the constructor and ensures that it is accessible.
       * The constructor signature must match the parameter types exactly.</p>
       *
       * @param <T> the constructor type
       * @param cls the class to find a constructor for, not {@code null}
       * @param parameterTypes the array of parameter types, {@code null} treated as empty
       * @return the constructor, {@code null} if no matching accessible constructor found
       * @see Class#getConstructor
       * @see #getAccessibleConstructor(java.lang.reflect.Constructor)
       * @throws NullPointerException if {@code cls} is {@code null}
       */
      public static <T> Constructor<T> getAccessibleConstructor(final Class<T> cls,
              final Class<?>... parameterTypes) {
          Objects.requireNonNull(cls, "cls");
          try {
              return getAccessibleConstructor(cls.getConstructor(parameterTypes));
          } catch (final NoSuchMethodException e) {
              return null;
          }
      }
  
      /**
       * Checks if the specified constructor is accessible.
       *
       * <p>This simply ensures that the constructor is accessible.</p>
       *
       * @param <T> the constructor type
       * @param ctor  the prototype constructor object, not {@code null}
       * @return the constructor, {@code null} if no matching accessible constructor found
       * @see SecurityManager
       * @throws NullPointerException if {@code ctor} is {@code null}
       */
      public static <T> Constructor<T> getAccessibleConstructor(final Constructor<T> ctor) {
          Objects.requireNonNull(ctor, "ctor");
          return MemberUtils.isAccessible(ctor)
                  && isAccessible(ctor.getDeclaringClass()) ? ctor : null;
      }
  
      /**
       * Finds an accessible constructor with compatible parameters.
       *
       * <p>This checks all the constructor and finds one with compatible parameters
       * This requires that every parameter is assignable from the given parameter types.
       * This is a more flexible search than the normal exact matching algorithm.</p>
       *
       * <p>First it checks if there is a constructor matching the exact signature.
       * If not then all the constructors of the class are checked to see if their
       * signatures are assignment-compatible with the parameter types.
       * The first assignment-compatible matching constructor is returned.</p>
      *
      * @param <T> the constructor type
      * @param cls  the class to find a constructor for, not {@code null}
      * @param parameterTypes find method with compatible parameters
      * @return the constructor, null if no matching accessible constructor found
      * @throws NullPointerException if {@code cls} is {@code null}
      */
     public static <T> Constructor<T> getMatchingAccessibleConstructor(final Class<T> cls,
             final Class<?>... parameterTypes) {
         Objects.requireNonNull(cls, "cls");
         // see if we can find the constructor directly
         // most of the time this works and it's much faster
         try {
             return MemberUtils.setAccessibleWorkaround(cls.getConstructor(parameterTypes));
         } catch (final NoSuchMethodException ignored) {
             // ignore
         }
         Constructor<T> result = null;
         /*
          * (1) Class.getConstructors() is documented to return Constructor<T> so as
          * long as the array is not subsequently modified, everything's fine.
          */
         final Constructor<?>[] ctors = cls.getConstructors();
 
         // return best match:
         for (Constructor<?> ctor : ctors) {
             // compare parameters
             if (MemberUtils.isMatchingConstructor(ctor, parameterTypes)) {
                 // get accessible version of constructor
                 ctor = getAccessibleConstructor(ctor);
                 if (ctor != null) {
                     MemberUtils.setAccessibleWorkaround(ctor);
                     if (result == null || MemberUtils.compareConstructorFit(ctor, result, parameterTypes) < 0) {
                         // temporary variable for annotation, see comment above (1)
                         @SuppressWarnings("unchecked")
                         final Constructor<T> constructor = (Constructor<T>) ctor;
                         result = constructor;
                     }
                 }
             }
         }
         return result;
     }
 
     /**
      * Returns a new instance of the specified class inferring the right constructor
      * from the types of the arguments.
      *
      * <p>This locates and calls a constructor.
      * The constructor signature must match the argument types by assignment compatibility.</p>
      *
      * @param <T> the type to be constructed
      * @param cls  the class to be constructed, not {@code null}
      * @param args  the array of arguments, {@code null} treated as empty
      * @return new instance of {@code cls}, not {@code null}
      *
      * @throws NullPointerException if {@code cls} is {@code null}
      * @throws NoSuchMethodException if a matching constructor cannot be found
      * @throws IllegalAccessException if invocation is not permitted by security
      * @throws InvocationTargetException if an error occurs on invocation
      * @throws InstantiationException if an error occurs on instantiation
      * @see #invokeConstructor(Class, Object[], Class[])
      */
     public static <T> T invokeConstructor(final Class<T> cls, Object... args)
             throws NoSuchMethodException, IllegalAccessException, InvocationTargetException,
             InstantiationException {
         args = ArrayUtils.nullToEmpty(args);
         return invokeConstructor(cls, args, ClassUtils.toClass(args));
     }
 
     /**
      * Returns a new instance of the specified class choosing the right constructor
      * from the list of parameter types.
      *
      * <p>This locates and calls a constructor.
      * The constructor signature must match the parameter types by assignment compatibility.</p>
      *
      * @param <T> the type to be constructed
      * @param cls  the class to be constructed, not {@code null}
      * @param args  the array of arguments, {@code null} treated as empty
      * @param parameterTypes  the array of parameter types, {@code null} treated as empty
      * @return new instance of {@code cls}, not {@code null}
      *
      * @throws NullPointerException if {@code cls} is {@code null}
      * @throws NoSuchMethodException if a matching constructor cannot be found
      * @throws IllegalAccessException if invocation is not permitted by security
      * @throws InvocationTargetException if an error occurs on invocation
      * @throws InstantiationException if an error occurs on instantiation
      * @see Constructor#newInstance
      */
     public static <T> T invokeConstructor(final Class<T> cls, Object[] args, Class<?>[] parameterTypes)
             throws NoSuchMethodException, IllegalAccessException, InvocationTargetException,
             InstantiationException {
         args = ArrayUtils.nullToEmpty(args);
         parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
         final Constructor<T> ctor = getMatchingAccessibleConstructor(cls, parameterTypes);
         if (ctor == null) {
             throw new NoSuchMethodException(
                 "No such accessible constructor on object: " + cls.getName());
         }
         if (ctor.isVarArgs()) {
             final Class<?>[] methodParameterTypes = ctor.getParameterTypes();
             args = MethodUtils.getVarArgs(args, methodParameterTypes);
         }
         return ctor.newInstance(args);
     }
 
     /**
      * Returns a new instance of the specified class inferring the right constructor
      * from the types of the arguments.
      *
      * <p>This locates and calls a constructor.
      * The constructor signature must match the argument types exactly.</p>
      *
      * @param <T> the type to be constructed
      * @param cls the class to be constructed, not {@code null}
      * @param args the array of arguments, {@code null} treated as empty
      * @return new instance of {@code cls}, not {@code null}
      *
      * @throws NullPointerException if {@code cls} is {@code null}
      * @throws NoSuchMethodException if a matching constructor cannot be found
      * @throws IllegalAccessException if invocation is not permitted by security
      * @throws InvocationTargetException if an error occurs on invocation
      * @throws InstantiationException if an error occurs on instantiation
      * @see #invokeExactConstructor(Class, Object[], Class[])
      */
     public static <T> T invokeExactConstructor(final Class<T> cls, Object... args)
             throws NoSuchMethodException, IllegalAccessException, InvocationTargetException,
             InstantiationException {
         args = ArrayUtils.nullToEmpty(args);
         return invokeExactConstructor(cls, args, ClassUtils.toClass(args));
     }
 
     /**
      * Returns a new instance of the specified class choosing the right constructor
      * from the list of parameter types.
      *
      * <p>This locates and calls a constructor.
      * The constructor signature must match the parameter types exactly.</p>
      *
      * @param <T> the type to be constructed
      * @param cls the class to be constructed, not {@code null}
      * @param args the array of arguments, {@code null} treated as empty
      * @param parameterTypes  the array of parameter types, {@code null} treated as empty
      * @return new instance of {@code cls}, not {@code null}
      *
      * @throws NullPointerException if {@code cls} is {@code null}
      * @throws NoSuchMethodException if a matching constructor cannot be found
      * @throws IllegalAccessException if invocation is not permitted by security
      * @throws InvocationTargetException if an error occurs on invocation
      * @throws InstantiationException if an error occurs on instantiation
      * @see Constructor#newInstance
      */
     public static <T> T invokeExactConstructor(final Class<T> cls, Object[] args,
             Class<?>[] parameterTypes) throws NoSuchMethodException, IllegalAccessException,
             InvocationTargetException, InstantiationException {
         args = ArrayUtils.nullToEmpty(args);
         parameterTypes = ArrayUtils.nullToEmpty(parameterTypes);
         final Constructor<T> ctor = getAccessibleConstructor(cls, parameterTypes);
         if (ctor == null) {
             throw new NoSuchMethodException(
                 "No such accessible constructor on object: "+ cls.getName());
         }
         return ctor.newInstance(args);
     }
 
     /**
      * Tests whether the specified class is generally accessible, i.e. is
      * declared in an entirely {@code public} manner.
      * @param type to check
      * @return {@code true} if {@code type} and any enclosing classes are
      *         {@code public}.
      */
     private static boolean isAccessible(final Class<?> type) {
         Class<?> cls = type;
         while (cls != null) {
             if (!ClassUtils.isPublic(cls)) {
                 return false;
             }
             cls = cls.getEnclosingClass();
         }
         return true;
     }
 
     /**
      * ConstructorUtils instances should NOT be constructed in standard
      * programming. Instead, the class should be used as
      * {@code ConstructorUtils.invokeConstructor(cls, args)}.
      *
      * <p>This constructor is {@code public} to permit tools that require a JavaBean
      * instance to operate.</p>
      */
     public ConstructorUtils() {
     }
 
 }