LayerType.java

package org.springframework.roo.classpath.layers;

/**
 * Typical layers within a user application. Roo is not limited to these layers
 * alone; layer-providing addons can specify any desired integer position in
 * order to appear in the correct part of the application architecture relative
 * to the core position values shown below.
 * 
 * @author Stefan Schmidt
 * @since 1.2.0
 */
public enum LayerType {

  /**
   * The pattern by which entities provide their own persistence methods.
   */
  ACTIVE_RECORD(20),

  /**
   * Infrastructure component that provides low-level persistence operations,
   * e.g. to a single table of a relational database. Usually implemented via
   * a specific persistence technology such as JPA or JDBC.
   */
  DAO(40),

  /**
   * The ultimate consumer of persistence-related operations, for example the
   * application's web or integration test layer.
   */
  HIGHEST(100),

  /**
   * Domain type that provides collection-like access to instances of
   * aggregate roots; implementations are usually persistence agnostic.
   */
  REPOSITORY(60),

  /**
   * Domain type that implements an application's use-cases.
   */
  SERVICE(80);

  private final int position;

  /**
   * Constructor
   * 
   * @param position the position of this layer relative to other layers
   */
  private LayerType(final int position) {
    this.position = position;
  }

  /**
   * Returns the position of this layer relative to other layers
   * 
   * @return any integer
   */
  public int getPosition() {
    return position;
  }
}