/*
    * 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;
  
  import java.io.Serializable;
  
  import javax.annotation.CheckForNull;
  
  import org.apache.commons.lang.ObjectUtils;
  
  import de.smartics.properties.api.config.domain.key.ApplicationId;
  import de.smartics.util.lang.Arg;
  
  /**
   * Identifies the location of a property.
   */
  public final class PropertyLocation implements Serializable,
      Comparable<PropertyLocation>
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     */
    private static final long serialVersionUID = 1L;
  
    // --- members --------------------------------------------------------------
  
    /**
     * The identifier of the application archive that contains the property. The
     * value may be <code>null</code> if no archive contains the information. This
     * is e.g. the case if the property is provided by a data source or other
     * external information system.
     *
     * @serial
     */
    private final ApplicationId applicationId;
  
    /**
     * The identifier of the property location within the application. The path
     * may serve as an ID like a JNDI name or name the path to a properties file
     * within the {@link #getApplicationId() archive}.
     * <p>
     * This value must not be <code>null</code>.
     * </p>
     *
     * @serial
     */
    private final String path;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Convenience constructor if no application identifier is available.
     *
     * @param path the identifier of the property location within the application.
     * @throws IllegalArgumentException if {@code path} is <code>null</code>.
     */
    public PropertyLocation(final String path) throws IllegalArgumentException
    {
      this(null, path);
    }
  
    /**
     * Default constructor.
     *
     * @param applicationId the identifier of the application archive that
     *          contains the property.
     * @param path the identifier of the property location within the application.
     * @throws IllegalArgumentException if {@code path} is <code>null</code>.
     */
    public PropertyLocation(final ApplicationId applicationId, final String path)
      throws IllegalArgumentException
    {
      this.applicationId = applicationId;
      this.path = Arg.checkNotBlank("path", path);
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   /**
    * Returns the identifier of the application archive that contains the
    * property. The value may be <code>null</code> if no archive contains the
    * information. This is e.g. the case if the property is provided by a data
    * source or other external information system.
    *
    * @return the identifier of the application archive that contains the
    *         property. May be <code>null</code>.
    */
   @CheckForNull
   public ApplicationId getApplicationId()
   {
     return applicationId;
   }
 
   /**
    * Returns the identifier of the property location within the application. The
    * path may serve as an ID like a JNDI name or name the path to a properties
    * file within the {@link #getApplicationId() archive}.
    * <p>
    * This value must not be <code>null</code>.
    * </p>
    *
    * @return the identifier of the property location within the application.
    */
   public String getPath()
   {
     return path;
   }
 
   // --- business -------------------------------------------------------------
 
   // --- object basics --------------------------------------------------------
 
   @Override
   public int compareTo(final PropertyLocation o)
   {
     int compare = ObjectUtils.compare(applicationId, o.applicationId);
     if (compare == 0)
     {
       compare = path.compareTo(o.path);
     }
 
     return compare;
   }
 
   /**
    * Returns the hash code of the object.
    *
    * @return the hash code.
    */
   @Override
   public int hashCode()
   {
     int result = 17;
     result = 37 * result + ObjectUtils.hashCode(applicationId);
     result = 37 * result + path.hashCode();
 
     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 PropertyLocation other = (PropertyLocation) object;
 
     return (ObjectUtils.equals(applicationId, other.applicationId) && path
         .equals(other.path));
   }
 
   /**
    * Returns the string representation of the object.
    *
    * @return the string representation of the object.
    */
   @Override
   public String toString()
   {
     final StringBuilder buffer = new StringBuilder();
 
     if (applicationId != null)
     {
       buffer.append(applicationId).append(':');
     }
 
     buffer.append(path);
 
     return buffer.toString();
   }
 }