/*
    * 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.beanutils2;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.util.HashMap;
  import java.util.Objects;
  
  /**
   * <p>
   * Minimal implementation of the {@code DynaClass} interface. Can be used as a convenience base class for more sophisticated implementations.
   * </p>
   * <p>
   * <strong>IMPLEMENTATION NOTE</strong> - The {@code DynaBean} implementation class supplied to our constructor MUST have a one-argument constructor of its own
   * that accepts a {@code DynaClass}. This is used to associate the DynaBean instance with this DynaClass.
   * </p>
   */
  public class BasicDynaClass implements DynaClass {
  
      private static final long serialVersionUID = 1L;
  
      /**
       * The method signature of the constructor we will use to create new DynaBean instances.
       */
      private static final Class<?>[] CONSTRUCTOR_TYPES = { DynaClass.class };
  
      /**
       * The constructor of the {@code dynaBeanClass} that we will use for creating new instances.
       */
      protected transient Constructor<?> constructor;
  
      /**
       * The argument values to be passed to the constructor we will use to create new DynaBean instances.
       */
      protected Object[] constructorValues = { this };
  
      /**
       * The {@code DynaBean} implementation class we will use for creating new instances.
       */
      protected Class<?> dynaBeanClass = BasicDynaBean.class;
  
      /**
       * The "name" of this DynaBean class.
       */
      protected String name = this.getClass().getName();
  
      /**
       * The set of dynamic properties that are part of this DynaClass.
       */
      protected DynaProperty[] properties = DynaProperty.EMPTY_ARRAY;
  
      /**
       * The set of dynamic properties that are part of this DynaClass, keyed by the property name. Individual descriptor instances will be the same instances as
       * those in the {@code properties} list.
       */
      protected HashMap<String, DynaProperty> propertiesMap = new HashMap<>();
  
      /**
       * Constructs a new BasicDynaClass with default parameters.
       */
      public BasicDynaClass() {
          this(null, null, null);
      }
  
      /**
       * Constructs a new BasicDynaClass with the specified parameters.
       *
       * @param name          Name of this DynaBean class
       * @param dynaBeanClass The implementation class for new instances
       */
      public BasicDynaClass(final String name, final Class<?> dynaBeanClass) {
          this(name, dynaBeanClass, null);
      }
  
      /**
       * Constructs a new BasicDynaClass with the specified parameters.
       *
       * @param name          Name of this DynaBean class
       * @param dynaBeanClass The implementation class for new instances
       * @param properties    Property descriptors for the supported properties
       */
      public BasicDynaClass(final String name, Class<?> dynaBeanClass, final DynaProperty[] properties) {
          if (name != null) {
             this.name = name;
         }
         if (dynaBeanClass == null) {
             dynaBeanClass = BasicDynaBean.class;
         }
         setDynaBeanClass(dynaBeanClass);
         if (properties != null) {
             setProperties(properties);
         }
     }
 
     /**
      * Gets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
      * {@code DynaBean} interface.
      *
      * @return The class of the {@link DynaBean}
      */
     public Class<?> getDynaBeanClass() {
         return this.dynaBeanClass;
     }
 
     /**
      * <p>
      * Return an array of {@code PropertyDescriptor} for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array
      * will be returned.
      * </p>
      *
      * <p>
      * <strong>FIXME</strong> - Should we really be implementing {@code getBeanInfo()} instead, which returns property descriptors and a bunch of other stuff?
      * </p>
      *
      * @return the set of properties for this DynaClass
      */
     @Override
     public DynaProperty[] getDynaProperties() {
         return properties.clone();
     }
 
     /**
      * Gets a property descriptor for the specified property, if it exists; otherwise, return {@code null}.
      *
      * @param name Name of the dynamic property for which a descriptor is requested
      * @return The descriptor for the specified property
      * @throws IllegalArgumentException if no property name is specified
      */
     @Override
     public DynaProperty getDynaProperty(final String name) {
         return propertiesMap.get(Objects.requireNonNull(name, "name"));
     }
 
     /**
      * Gets the name of this DynaClass (analogous to the {@code getName()} method of {@link Class}, which allows the same {@code DynaClass} implementation class
      * to support different dynamic classes, with different sets of properties.
      *
      * @return the name of the DynaClass
      */
     @Override
     public String getName() {
         return this.name;
     }
 
     /**
      * Instantiate and return a new DynaBean instance, associated with this DynaClass.
      *
      * @return A new {@code DynaBean} instance
      * @throws IllegalAccessException if the Class or the appropriate constructor is not accessible
      * @throws InstantiationException if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some
      *                                other reason
      */
     @Override
     public DynaBean newInstance() throws IllegalAccessException, InstantiationException {
         try {
             // Refind the constructor after a deserialization (if needed)
             if (constructor == null) {
                 setDynaBeanClass(this.dynaBeanClass);
             }
             // Invoke the constructor to create a new bean instance
             return (DynaBean) constructor.newInstance(constructorValues);
         } catch (final InvocationTargetException e) {
             throw new InstantiationException(e.getTargetException().getMessage());
         }
     }
 
     /**
      * Sets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
      * {@code DynaBean} interface.
      *
      * @param dynaBeanClass The new Class object
      * @throws IllegalArgumentException if the specified Class does not implement the {@code DynaBean} interface
      */
     protected void setDynaBeanClass(final Class<?> dynaBeanClass) {
         // Validate the argument type specified
         if (dynaBeanClass.isInterface()) {
             throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " is an interface, not a class");
         }
         if (!DynaBean.class.isAssignableFrom(dynaBeanClass)) {
             throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not implement DynaBean");
         }
 
         // Identify the Constructor we will use in newInstance()
         try {
             this.constructor = dynaBeanClass.getConstructor(CONSTRUCTOR_TYPES);
         } catch (final NoSuchMethodException e) {
             throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not have an appropriate constructor");
         }
         this.dynaBeanClass = dynaBeanClass;
     }
 
     /**
      * Sets the list of dynamic properties supported by this DynaClass.
      *
      * @param properties List of dynamic properties to be supported
      */
     protected void setProperties(final DynaProperty[] properties) {
         this.properties = Objects.requireNonNull(properties, "properties");
         propertiesMap.clear();
         for (final DynaProperty property : properties) {
             propertiesMap.put(property.getName(), property);
         }
     }
 
 }