/*
    *    Copyright 2012-2022 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
    *
    *       https://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.mybatis.caches.memcached;
  
  import java.beans.BeanInfo;
  import java.beans.IntrospectionException;
  import java.beans.Introspector;
  import java.beans.PropertyDescriptor;
  import java.lang.reflect.Method;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  
  /**
   * Converts a keyed property string in the Config to a proper Java object representation.
   *
   * @author Simone Tripodi
   */
  abstract class AbstractPropertySetter<T> {
  
    /**
     * 'propertyName'='writermethod' index of {@link MemcachedConfiguration} properties.
     */
    private static Map<String, Method> WRITERS = new HashMap<String, Method>();
  
    static {
      try {
        BeanInfo memcachedConfigInfo = Introspector.getBeanInfo(MemcachedConfiguration.class);
        for (PropertyDescriptor descriptor : memcachedConfigInfo.getPropertyDescriptors()) {
          WRITERS.put(descriptor.getName(), descriptor.getWriteMethod());
        }
      } catch (IntrospectionException e) {
        // handle quietly
      }
    }
  
    /**
     * The Config property key.
     */
    private final String propertyKey;
  
    /**
     * The {@link MemcachedConfiguration} property name.
     */
    private final String propertyName;
  
    /**
     * The {@link MemcachedConfiguration} property method writer.
     */
    private final Method propertyWriterMethod;
  
    /**
     * The default value used if something goes wrong during the conversion or the property is not set in the config.
     */
    private final T defaultValue;
  
    /**
     * Build a new property setter.
     *
     * @param propertyKey
     *          the Config property key.
     * @param propertyName
     *          the {@link MemcachedConfiguration} property name.
     * @param defaultValue
     *          the property default value.
     */
    public AbstractPropertySetter(final String propertyKey, final String propertyName, final T defaultValue) {
      this.propertyKey = propertyKey;
      this.propertyName = propertyName;
  
      this.propertyWriterMethod = WRITERS.get(propertyName);
      if (this.propertyWriterMethod == null) {
        throw new RuntimeException(
            "Class '" + MemcachedConfiguration.class.getName() + "' doesn't contain a property '" + propertyName + "'");
      }
  
      this.defaultValue = defaultValue;
    }
  
    /**
     * Extract a property from the, converts and puts it to the {@link MemcachedConfiguration}.
     *
     * @param config
     *          the Config
     * @param memcachedConfiguration
     *          the {@link MemcachedConfiguration}
    */
   public final void set(Properties config, MemcachedConfiguration memcachedConfiguration) {
     String propertyValue = config.getProperty(propertyKey);
     T value;
 
     try {
       value = this.convert(propertyValue);
       if (value == null) {
         value = defaultValue;
       }
     } catch (Exception e) {
       value = defaultValue;
     }
 
     try {
       propertyWriterMethod.invoke(memcachedConfiguration, value);
     } catch (Exception e) {
       throw new RuntimeException("Impossible to set property '" + propertyName + "' with value '" + value
           + "', extracted from ('" + propertyKey + "'=" + propertyValue + ")", e);
     }
   }
 
   /**
    * Convert a string representation to a proper Java Object.
    *
    * @param value
    *          the value has to be converted.
    *
    * @return the converted value.
    *
    * @throws Exception
    *           if any error occurs.
    */
   protected abstract T convert(String value) throws Exception;
 
 }