/*
    * Copyright 2008-2010 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.maven.issues.util;
  
  import org.apache.commons.lang.builder.ToStringBuilder;
  import org.apache.maven.artifact.versioning.ArtifactVersion;
  
  /**
   * A simple model for report references.
   *
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public class ReportReference implements Comparable<ReportReference>
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The label to display.
     */
    private final String label;
  
    /**
     * The URL to the references report.
     */
    private final String url;
  
    /**
     * The representative for the versions in this report. Since reports may
     * contain a range of versions this representative is the first version to be
     * reported about. It is assumed that all reports are disjunct, report over at
     * least on version and all versions are consecutive. In addition to that, if
     * the version reference is prior to another version, all versions in the
     * report referenced by this instance are also prior.
     * <p>
     * The ordering of report references is determined by this representative.
     * </p>
     */
    private final ArtifactVersion versionRepresentative;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param label the label to display.
     * @param url the URL to the references report.
     * @param versionRepresentative the representative for the versions in this
     *          report.
     * @throws NullPointerException if any parameter is <code>null</code>.
     */
    public ReportReference(final String label, final String url,
        final ArtifactVersion versionRepresentative) throws NullPointerException
    {
      checkPrecondition(label, url, versionRepresentative);
      this.label = label;
      this.url = url + ".html";
      this.versionRepresentative = versionRepresentative;
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    /**
     * Checks if each given value is not <code>null</code>.
     *
     * @param label value to check to be not <code>null</code>.
     * @param url value to check to be not <code>null</code>.
     * @param versionRepresentative value to check to be not <code>null</code>.
     * @throws NullPointerException if any parameter is <code>null</code>.
     */
    private void checkPrecondition(final String label, final String url,
        final ArtifactVersion versionRepresentative) throws NullPointerException
    {
      if (label == null)
      {
       throw new NullPointerException("Label must not be 'null'.");
     }
     if (url == null)
     {
       throw new NullPointerException("URL must not be 'null'.");
     }
     if (versionRepresentative == null)
     {
       throw new NullPointerException(
           "Version representative must not be 'null' because it is responsible for sorting.");
     }
   }
 
   // --- get&set --------------------------------------------------------------
 
   /**
    * Returns the label to display.
    *
    * @return the label to display.
    */
   public String getLabel()
   {
     return label;
   }
 
   /**
    * Returns the URL to the references report.
    *
    * @return the URL to the references report.
    */
   public String getUrl()
   {
     return url;
   }
 
   /**
    * Returns the representative for the versions in this report. Since reports
    * may contain a range of versions this representative is the first version to
    * be reported about. It is assumed that all reports are disjunct, report over
    * at least on version and all versions are consecutive. In addition to that,
    * if the version reference is prior to another version, all versions in the
    * report referenced by this instance are also prior.
    * <p>
    * The ordering of report references is determined by this representative.
    * </p>
    *
    * @return the representative for the versions in this report.
    */
   public ArtifactVersion getVersionRepresentative()
   {
     return versionRepresentative;
   }
 
   // --- business -------------------------------------------------------------
 
   // --- object basics --------------------------------------------------------
 
   /**
    * Returns the hash code of the object.
    *
    * @return the hash code.
    */
   @Override
   public int hashCode()
   {
     return versionRepresentative.toString().hashCode();
   }
 
   /**
    * 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 ReportReference other = (ReportReference) object;
 
     return (url.equals(other.url) && versionRepresentative.toString().equals(
         other.versionRepresentative.toString()));
   }
 
   /**
    * {@inheritDoc}
    *
    * @see java.lang.Comparable#compareTo(java.lang.Object)
    */
   public int compareTo(final ReportReference o)
   {
     int compare = url.compareTo(o.url);
     if (compare == 0)
     {
       compare =
           InverseVersionComparator.INSTANCE.compare(versionRepresentative,
               o.versionRepresentative);
     }
     return compare;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see java.lang.Object#toString()
    */
   @Override
   public String toString()
   {
     return ToStringBuilder.reflectionToString(this);
   }
 }