/*
    * 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));
     }
   }
 
 }