content: package org.apache.archiva.repository.content;
  
  /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.
   */
  
  /**
   * Represents a artifact of a repository. This object contains unique coordinates of the
   * artifact. A artifact has exactly one file representation in the repository.
   * The artifact instance does not tell, if the file exists or is readable. It just
   * keeps the coordinates and some meta information of the artifact.
   * <p>
   * Artifact implementations should be immutable. The implementation must not always represent the current state of the
   * corresponding storage asset (file). It is just a view of the attributes for a given point in time.
   * <p>
   * Implementations must provide proper hash and equals methods.
   *
   * @author Martin Stockhammer <martin_s@apache.org>
   */
  public interface Artifact extends DataItem
  {
  
      /**
       * The artifact identifier. The ID is unique in a given namespace of a given repository.
       * But there may exist artifacts with the same ID but different types, classifiers or extensions.
       * <p>
       * Never returns <code>null</code> or a empty string.
       *
       * @return the identifier of the artifact. Never returns <code>null</code> or empty string
       */
      @Override
      String getId( );
  
      /**
       * The version string of the artifact. The version string is exactly the version that is attached
       * to the artifact.
       * The version string may be different to the version string returned by the attached {@link Version} object.
       * E.g for maven artifacts the artifact version may be 1.3-20070725.210059-1 and the attached {@link Version} object
       * has version 1.3-SNAPSHOT.
       *
       * @return the artifact version string
       * @see #getVersion()
       */
      String getArtifactVersion( );
  
      /**
       * Returns the project this artifact is attached to
       * @return the project
       */
      Project getProject();
  
      /**
       * Returns the namespace this artifact is attached to
       * @return the namespace object
       */
      Namespace getNamespace();
  
      /**
       * Returns the attached version this artifact is part of.
       *
       * @return the version object
       */
      Version getVersion( );
  
      /**
       * Returns the type of the artifact. The type is some hint about the usage of the artifact.
       * Implementations may always return a empty string, if it is not used.
       *
       * @return the type of the artifact. Returns never <code>null</code>, but may be empty string
       */
      String getType( );
  
      /**
       * A classifier that distinguishes artifacts.
       * Implementations may always return a empty string, if it is not used.
       *
       * @return the classifier of the artifact. Returns never <code>null</code>, but may be empty string
       */
      String getClassifier( );
  
      /**
       * This may be different from extension and gives the remainder that is used to build the file path from
       * the artifact coordinates (namespace, id, version, classifier, type)
       *
       * @return the file name remainder
       */
      String getRemainder( );
  
      /**
       * Returns the type of the artifact
       * @return
       */
      @Override
      ArtifactType getDataType();
  
      /**
       * Returns a unique key
       * @return
       */
      String toKey();
  
  
      /**
       * Short cut for the file name. Should always return the same value as the artifact name.
       *
       * @return the name of the file
       */
      @Override
      default String getFileName( )
      {
          return getAsset( ).getName( );
      }
  
      /**
       * Returns the extension of the file. This method should always return the extension string after the last
       * '.'-character.
       *
       * @return the file name extension
       */
      @Override
      default String getExtension( )
      {
          final String name = getAsset( ).getName( );
          final int idx = name.lastIndexOf( '.' )+1;
          if ( idx > 0 )
          {
              return name.substring( idx );
          }
          else
          {
              return "";
          }
      }
  
      default ContentItem getParent( )
      {
          return getVersion();
      }
  }
  