LayerProvider.java

package org.springframework.roo.classpath.layers;

import org.springframework.roo.model.JavaType;

/**
 * Provides persistence-related methods at a given layer of the application.
 * 
 * @author Stefan Schmidt
 * @since 1.2.0
 */
public interface LayerProvider {

  /**
   * The priority of the core layers.
   */
  int CORE_LAYER_PRIORITY = 0;

  /**
   * Returns the position of this layer relative to others.
   * 
   * @return a large number for higher-level layers, a smaller number for
   *         lower-level layers
   */
  int getLayerPosition();

  /**
   * A layer provider should determine if it can provide
   * {@link MemberTypeAdditions} for a given target entity and construct it
   * accordingly. If it can not provide the requested functionality it should
   * simply return null;
   * 
   * @param callerMID the caller's metadata ID
   * @param methodIdentifier specifies the method which is being requested
   * @param targetEntity specifies the target entity
   * @param idType specifies the ID type used by the target entity
   * @param autowire specified where the addition should be autowired (if
   *            applicable)
   * @param methodParameters parameters which are passed in to the method
   * @return {@link MemberTypeAdditions} if a layer provider can offer this
   *         functionality, null otherwise
   */
  MemberTypeAdditions getMemberTypeAdditions(String callerMID, String methodIdentifier,
      JavaType targetEntity, JavaType idType, boolean autowire, MethodParameter... methodParameters);

  /**
   * A layer provider should determine if it can provide
   * {@link MemberTypeAdditions} for a given target entity and construct it
   * accordingly. If it can not provide the requested functionality it should
   * simply return null;
   * 
   * @param callerMID the caller's metadata ID
   * @param methodIdentifier specifies the method which is being requested
   * @param targetEntity specifies the target entity
   * @param idType specifies the ID type used by the target entity
   * @param methodParameters parameters which are passed in to the method
   * @return {@link MemberTypeAdditions} if a layer provider can offer this
   *         functionality, null otherwise
   */
  MemberTypeAdditions getMemberTypeAdditions(String callerMID, String methodIdentifier,
      JavaType targetEntity, JavaType idType, MethodParameter... methodParameters);

  /**
   * Returns the priority of this layer relative to other implementations with
   * the same position.
   * 
   * @return a value greater than {@link #CORE_LAYER_PRIORITY} in order to
   *         take precedence over the core {@link LayerProvider}s
   * @see #getLayerPosition()
   */
  int getPriority();
}