/*
    * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.properties.api.config.app;
  
  import java.io.Serializable;
  import java.util.Iterator;
  import java.util.ServiceConfigurationError;
  import java.util.ServiceLoader;
  
  import javax.annotation.concurrent.ThreadSafe;
  
  import org.apache.commons.lang.builder.ToStringBuilder;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import de.smartics.properties.api.core.security.Base64PropertyValueSecurity;
  import de.smartics.properties.api.core.security.PropertyValueSecurity;
  
  /**
   * Provides properties to configure an instance of
   * {@link de.smartics.properties.api.config.app.ConfigurationPropertiesFactory}.
   */
  @ThreadSafe
  public final class FactoryConfiguration implements Serializable
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     */
    private static final long serialVersionUID = 1L;
  
    /**
     * Reference to the logger for this class.
     */
    private static final Logger LOG = LoggerFactory
        .getLogger(FactoryConfiguration.class);
  
    // --- members --------------------------------------------------------------
  
    /**
     * The flag to tell whether (<code>true</code>) or not (<code>false</code>)
     * the URLs of the context class loader should be added.
     *
     * @serial
     */
    private volatile boolean addDefaultRootLocations = true;
  
    /**
     * The flag indicates that loading properties form the class path is to be
     * skipped.
     *
     * @serial
     */
    private volatile boolean skipClassPathPropertyLoading;
  
    /**
     * The flag indicates that a cache should be provided, if supported.
     *
     * @serial
     */
    private volatile boolean useCache = true;
  
    /**
     * The helper to decrypt secured property values.
     *
     * @serial
     */
    private volatile PropertyValueSecurity decrypter = createDecrypter();
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     */
    public FactoryConfiguration()
    {
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   /**
    * Returns the flag to tell whether (<code>true</code>) or not (
    * <code>false</code>) the URLs of the context class loader should be added.
    *
    * @return the flag to tell whether (<code>true</code>) or not (
    *         <code>false</code>) the URLs of the context class loader should be
    *         added.
    */
   public boolean isAddDefaultRootLocations()
   {
     return addDefaultRootLocations;
   }
 
   /**
    * Sets the flag to tell whether (<code>true</code>) or not (
    * <code>false</code>) the URLs of the context class loader should be added.
    *
    * @param addDefaultRootLocations the flag to tell whether (<code>true</code>)
    *          or not (<code>false</code>) the URLs of the context class loader
    *          should be added.
    */
   public void setAddDefaultRootLocations(final boolean addDefaultRootLocations)
   {
     this.addDefaultRootLocations = addDefaultRootLocations;
   }
 
   /**
    * Returns the flag indicates that loading properties form the class path is
    * to be skipped.
    *
    * @return the flag indicates that loading properties form the class path is
    *         to be skipped.
    */
   public boolean isSkipClassPathPropertyLoading()
   {
     return skipClassPathPropertyLoading;
   }
 
   /**
    * Sets the flag indicates that loading properties from the class path is to
    * be skipped.
    *
    * @param skipClassPathPropertyLoading the flag indicates that loading
    *          properties from the class path is to be skipped.
    */
   public void setSkipClassPathPropertyLoading(
       final boolean skipClassPathPropertyLoading)
   {
     this.skipClassPathPropertyLoading = skipClassPathPropertyLoading;
   }
 
   /**
    * Returns the flag indicates that a cache should be provided, if supported.
    *
    * @return the flag indicates that a cache should be provided, if supported.
    */
   public boolean isUseCache()
   {
     return useCache;
   }
 
   /**
    * Sets the flag indicates that a cache should be provided, if supported.
    *
    * @param useCache the flag indicates that a cache should be provided, if
    *          supported.
    */
   public void setUseCache(final boolean useCache)
   {
     this.useCache = useCache;
   }
 
   /**
    * Returns the helper to decrypt secured property values.
    *
    * @return the helper to decrypt secured property values.
    */
   public PropertyValueSecurity getDecrypter()
   {
     return decrypter;
   }
 
   /**
    * Sets the helper to decrypt secured property values.
    *
    * @param decrypter the helper to decrypt secured property values.
    */
   public void setDecrypter(final PropertyValueSecurity decrypter)
   {
     this.decrypter = decrypter;
   }
 
   // --- business -------------------------------------------------------------
 
   /**
    * Creates an instance of {@link PropertyValueSecurity} as registered in
    * <code>META-INF/services/de.smartics.properties.api.core.security.PropertyValueSecurity</code>
    * .
    * <p>
    * Issues a warning if more than one implementation is found. If no
    * implementation is configured, a non-secure instance is returned.
    * </p>
    *
    * @return the instance of a decrypter. Never <code>null</code>.
    */
   private PropertyValueSecurity createDecrypter()
   {
     final Iterator<PropertyValueSecurity> iterator =
         ServiceLoader.load(PropertyValueSecurity.class).iterator();
 
     final StringBuilder buffer = new StringBuilder(64);
     PropertyValueSecurity security = null;
     while (iterator.hasNext())
     {
       try
       {
         if (security != null)
         {
           final String implementation = iterator.next().getClass().getName();
           buffer.append("\nDuplicated implementation rejected: "
                         + implementation);
           continue;
         }
 
         security = iterator.next();
       }
       catch (final ServiceConfigurationError e)
       {
         buffer.append("\nError encountered: ").append(e.getMessage());
       }
     }
 
     if (buffer.length() > 0)
     {
       LOG.warn("Problems encountered while fetching implementations of '"
                + PropertyValueSecurity.class.getName() + "':" + buffer);
     }
 
     if (security == null)
     {
       return new Base64PropertyValueSecurity();
     }
 
     return security;
   }
 
   // --- object basics --------------------------------------------------------
 
   /**
    * {@inheritDoc}
    * <p>
    * Provides the properties via reflection for displaying debug information.
    * </p>
    * <p>
    * Please note that calling this method may not be thread-safe. The flag
    * printed may not reflect an actual state or a state that ever existed.
    * </p>
    *
    * @see java.lang.Object#toString()
    */
   @Override
   public String toString()
   {
     return ToStringBuilder.reflectionToString(this);
   }
 }