/*

  * 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 static org.apache.commons.lang.StringUtils.defaultIfBlank;

 import org.apache.commons.lang.ObjectUtils;

 import de.smartics.util.lang.Arg;

 /**

  * The coordinates to identify an application.

  */

 public final class ApplicationId implements Serializable,

     Comparable<ApplicationId>

 {

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

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

   /**

    * The class version identifier.

    * <p>

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

    * </p>

    */

   private static final long serialVersionUID = 1L;

   /**

    * Defines the application for any group, name and version.

    */

   public static final ApplicationId ANY_APP = new ApplicationId(null, null,

       null);

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

   /**

    * The group the application belongs to.

    *

    * @serial

    */

   private final String groupId;

   /**

    * The name of the application.

    *

    * @serial

    */

   private final String artifactId;

   /**

    * The version of the application.

    *

    * @serial

    */

   private final String version;

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

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

   /**

    * Default constructor.

    *

    * @param groupId the group the application belongs to. May be

    *          <code>null</code>

    * @param artifactId the name of the application. May be <code>null</code>.

    * @param version the version of the application. May be <code>null</code>.

    * @throws IllegalArgumentException if either parameter is the empty string or

    *           contains only white spaces.

    */

   public ApplicationId(final String groupId, final String artifactId,

       final String version) throws IllegalArgumentException

   {

     this.groupId = Arg.checkNotBlankExceptNull("groupId", groupId);

     this.artifactId = Arg.checkNotBlankExceptNull("artifactId", artifactId);

     this.version = Arg.checkNotBlankExceptNull("version", version);

   }

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

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

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

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

   /**

    * Returns the group the application belongs to.

    *

    * @return the group the application belongs to. May be <code>null</code>.

    */

   public String getGroupId()

   {

     return groupId;

   }

   /**

    * Returns the name of the application.

    *

    * @return the name of the application. May be <code>null</code>.

    */

   public String getArtifactId()

   {

     return artifactId;

   }

   /**

    * Returns the version of the application.

    *

    * @return the version of the application. May be <code>null</code>.

    */

   public String getVersion()

   {

     return version;

   }

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

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

   /**

    * Returns the hash code of the object.

    *

    * @return the hash code.

    */

   @Override

   public int hashCode()

   {

     int result = 17;

     result = 37 * result + ObjectUtils.hashCode(artifactId);

     result = 37 * result + ObjectUtils.hashCode(groupId);

     result = 37 * result + ObjectUtils.hashCode(version);

     return result;

   }

   /**

    * 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 ApplicationId other = (ApplicationId) object;

     return (ObjectUtils.equals(artifactId, other.artifactId)

             && ObjectUtils.equals(groupId, other.groupId) && ObjectUtils

         .equals(version, other.version));

   }

   /**

    * {@inheritDoc}

    *

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

    */

   @Override

   public int compareTo(final ApplicationId o)

   {

     int result = ObjectUtils.compare(artifactId, o.artifactId);

     if (result == 0)

     {

       result = ObjectUtils.compare(groupId, o.groupId);

       if (result == 0)

       {

         result = ObjectUtils.compare(version, o.version);

       }

     }

     return result;

   }

   /**

    * Returns the string representation of the object as a path. All elements are

    * separated by a slash.

    *

    * @return the string representation of the object.

    */

   public String toPath()

   {

     final StringBuilder buffer = new StringBuilder();

     if (groupId != null)

     {

       buffer.append(groupId);

     }

     if (artifactId != null)

     {

       buffer.append('/');

       buffer.append(artifactId);

     }

     if (version != null)

     {

       buffer.append('/');

       buffer.append(version);

     }

     return buffer.toString();

   }

   /**

    * Returns the string representation of the object. The GAV elements are

    * separated by a colon. If any element is <code>null</code>, the empty string

    * is appended. If no element is specified, the returned string is

    * <code>::</code>.

    *

    * @return the string representation of the object.

    */

   @Override

   public String toString()

   {

     final StringBuilder buffer = new StringBuilder();

     if (groupId != null)

     {

       buffer.append(groupId);

     }

     buffer.append(':');

     if (artifactId != null)

     {

       buffer.append(artifactId);

     }

     buffer.append(':');

     if (version != null)

     {

       buffer.append(version);

     }

     return buffer.toString();

   }

   /**

    * Returns an {@link ApplicationId} for the given String or throws an

    * {@link IllegalArgumentException} if the String is not valid.

    *

    * @param applicationString a string describing an applicationId.

    * @return an applicationId for the given String.

    * @throws IllegalArgumentException if an invalid applicationString has been

    *           passed.

    */

   public static ApplicationId valueOf(final String applicationString)

     throws IllegalArgumentException

   {

     if (applicationString == null)

     {

       return ApplicationId.ANY_APP;

     }

     final String[] applicationParts = applicationString.split(":", -1);

     final int length = applicationParts.length;

     if (length < 3)

     {

       throw new IllegalArgumentException(

           String

               .format(

                   "Could not create an instance out of the key %s. It has too less delimiters!",

                   applicationString));

     }

     else if (length == 3)

     {

       return new ApplicationId(defaultIfBlank(applicationParts[0], null),

           defaultIfBlank(applicationParts[1], null), defaultIfBlank(

               applicationParts[2], null));

     }

     else

     {

       throw new IllegalArgumentException(

           String

               .format(

                   "Could not create an instance out of the key %s. It has too many delimiters!",

                   applicationString));

     }

   }

 }