/*

  * 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.domain.key;

 import java.io.Serializable;

 import org.apache.commons.lang.StringUtils;

 import de.smartics.util.lang.Arguments;

 import de.smartics.util.lang.NullArgumentException;

 /**

  * The configuration key identifies a configuration. With this key all

  * configuration values can be accessed by their local configuration keys.

  */

 public final class ConfigurationKey implements Serializable,

     Comparable<ConfigurationKey>

 {

   // ********************************* Fields *********************************

   // --- constants ------------------------------------------------------------

   /**

    * The class version identifier.

    * <p>

    * The value of this constant is {@value}.

    * </p>

    */

   private static final long serialVersionUID = 1L;

   // --- members --------------------------------------------------------------

   /**

    * The identifier of the environment the application is deployed in.

    *

    * @serial

    */

   private final EnvironmentId environmentId;

   /**

    * The identifier of the application whose configuration is requested.

    *

    * @serial

    */

   private final ApplicationId applicationId;

   /**

    * The pre-calculated hash code of this instance.

    *

    * @serial

    */

   private final int hashCodeValue;

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   /**

    * Default constructor.

    *

    * @param applicationId the identifier of the application whose configuration

    *          is requested.

    * @param environmentId the identifier of the environment the application is

    *          deployed in.

    * @throws NullArgumentException if {@code applicationId} or

    *           {@code environmentId} is <code>null</code>.

    */

   public ConfigurationKey(final EnvironmentId environmentId, final ApplicationId applicationId

       ) throws NullArgumentException

   {

     Arguments.checkNotNull("environmentId", environmentId);

     Arguments.checkNotNull("applicationId", applicationId);

     this.environmentId = environmentId;

     this.applicationId = applicationId;

     this.hashCodeValue = calcHashCode();

   }

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   private int calcHashCode()

   {

     int result = 17;

     result = 37 * result + environmentId.hashCode();

     result = 37 * result + applicationId.hashCode();

     return result;

   }

   // --- get&set --------------------------------------------------------------

   /**

    * Returns the identifier of the environment the application is deployed in.

    *

    * @return the identifier of the environment the application is deployed in.

    */

   public EnvironmentId getEnvironmentId()

   {

     return environmentId;

   }

   /**

    * Returns the identifier of the application whose configuration is requested.

    *

    * @return the identifier of the application whose configuration is requested.

    */

   public ApplicationId getApplicationId()

   {

     return applicationId;

   }

   // --- business -------------------------------------------------------------

   // --- object basics --------------------------------------------------------

   /**

    * Returns the hash code of the object.

    *

    * @return the hash code.

    */

   @Override

   public int hashCode()

   {

     return hashCodeValue;

   }

   /**

    * Returns <code>true</code> if the given object is semantically equal to the

    * given object, <code>false</code> otherwise.

    *

    * @param object the instance to compare to.

    * @return <code>true</code> if the given object is semantically equal to the

    *         given object, <code>false</code> otherwise.

    */

   @Override

   public boolean equals(final Object object)

   {

     if (this == object)

     {

       return true;

     }

     else if (object == null || getClass() != object.getClass())

     {

       return false;

     }

     final ConfigurationKey other = (ConfigurationKey) object;

     return (applicationId.equals(other.applicationId) && environmentId

         .equals(other.environmentId));

   }

   /**

    * {@inheritDoc}

    *

    * @see java.lang.Comparable#compareTo(java.lang.Object)

    */

   @Override

   public int compareTo(final ConfigurationKey o)

   {

     final int result = environmentId.compareTo(o.environmentId);

     if (result == 0)

     {

       return applicationId.compareTo(o.applicationId);

     }

     return result;

   }

   /**

    * Returns the string representation of the object.

    *

    * @return the string representation of the object.

    */

   @Override

   public String toString()

   {

     final StringBuilder buffer = new StringBuilder();

     final String environmentIdString = environmentId.toString();

     if(StringUtils.isNotBlank(environmentIdString))

     {

       buffer.append(environmentIdString).append('/');

     }

     final String applicationIdString = applicationId.toString();

     if(StringUtils.isNotBlank(applicationIdString))

     {

       buffer.append(applicationIdString);

     }

     if(buffer.length() == 0)

     {

       buffer.append("<no named key>");

     }

     return buffer.toString();

   }

 }