de.fraunhofer.iese.ind2uce.registry.InterfaceDescriptionDiscovery Maven / Gradle / Ivy

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/*-
 * =================================LICENSE_START=================================
 * IND2UCE
 * %%
 * Copyright (C) 2016 Fraunhofer IESE (www.iese.fraunhofer.de)
 * %%
 * 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.
 * =================================LICENSE_END=================================
 */

package de.fraunhofer.iese.ind2uce.registry;

import de.fraunhofer.iese.ind2uce.api.component.description.InputParameterDescription;
import de.fraunhofer.iese.ind2uce.api.component.description.MethodInterfaceDescription;
import de.fraunhofer.iese.ind2uce.api.component.identifier.EnforcementScopeId;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Generates a List of {@link MethodInterfaceDescription} by introspecting a
 * class.
 * Therefor the discovery lists all methods that is annotated with an Annotation
 * of Type {@link ActionDescription} and creates an instance of
 * {@link MethodInterfaceDescription} with the information provided by the
 * MethodSignature, the annotation and the {@link ActionParameterDescription}
 * annotations of each method parameter.
 * For Example The Method
 *
 *  *
 *
 * {@literal @}ActionDescription(description = "Retreives the authority (role) of an user")
 *  public String getAuthority(@ActionParameterDescription(name = "username", description = "The user the authority should be evaluated for.", mandatory = true) String username) {
 *  }
 * 
 *
 * Results in an InterfaceDescription with:
 * 
 * name = getAuthority
 * description = Retreives the authority (role) of an user
 * parameter =
 * 
 * InputParameterDescription: name = username, description = The user the
 * authority should be evaluated for, mandatory = true
 * 
 * 
 * 
 */
class InterfaceDescriptionDiscovery {

  /**
   * Compose interface description.
   *
   * @param method the method
   * @param prefix the prefix
   * @param actionDescription the action description
   * @param name the name
   * @return the interface description
   */
  protected MethodInterfaceDescription composeInterfaceDescription(Method method, String prefix, ActionDescription actionDescription, String name) {
    return new MethodInterfaceDescription(prefix + ":" + name, method.getReturnType(), actionDescription.description(), this.readParameter(method));
  }

  /**
   * Creates the input parameter description.
   *
   * @param parameterType the parameter type
   * @param annotations the annotations
   * @param index the index
   * @return the input parameter description
   */
  private InputParameterDescription createInputParameterDescription(Class parameterType, Annotation[] annotations, int index) {
    final ActionParameterDescription annotation = this.getParameterDescriptionAnnotation(annotations);

    if (annotation != null) {
      final String parameterName = annotation.name();
      final String description = annotation.description();
      parameterType = annotation.type().equals(Void.class) ? parameterType : annotation.type();
      return new InputParameterDescription(parameterName, description, annotation.pattern(), annotation.mandatory(), parameterType);
    }
    if (this.isActionParameterDescriptionNecessary(parameterType, index)) {
      throw new IllegalStateException("Not all parameters are documented.");
    } else {
      return null;
    }
  }

  /**
   * Creates the interface description from service method.
   *
   * @param service the service
   * @param method the method
   * @param prefix the prefix
   * @return the map< interface description,? extends pair< method, object>>
   */
  protected Map> createInterfaceDescriptionFromServiceMethod(Object service, Method method, String prefix) {
    final ActionDescription actionDescription = method.getAnnotation(ActionDescription.class);
    final String name = this.readName(method, actionDescription);
    this.readParameter(method);
    return Collections.singletonMap(this.composeInterfaceDescription(method, prefix, actionDescription, name), new ImmutablePair<>(method, service));
  }

  /**
   * Discover.
   *
   * @param service the service
   * @param type the type
   * @param enforcementScopeId the enforcement scope id
   * @return the map
   */
  Map> discover(Object service, ComponentType type, EnforcementScopeId enforcementScopeId) {
    final String enforcementScope = this.getEnforcementScopeId(enforcementScopeId);
    final Map> toReturn = new HashMap<>();
    for (final Method method : service.getClass().getMethods()) {
      if (this.isServiceMethod(method)) {
        toReturn.putAll(this.createInterfaceDescriptionFromServiceMethod(service, method, type.getPrefixForInterfaceDescription() + enforcementScope));
      }
    }
    return toReturn;
  }

  /**
   * Gets the enforcement scope id.
   *
   * @param enforcementScopeId the enforcement scope id
   * @return the enforcement scope id
   */
  private String getEnforcementScopeId(EnforcementScopeId enforcementScopeId) {
    return enforcementScopeId.getIdentifier();
  }

  /**
   * Gets the parameter description annotation.
   *
   * @param annotations the annotations
   * @return the parameter description annotation
   */
  private ActionParameterDescription getParameterDescriptionAnnotation(Annotation[] annotations) {
    for (final Annotation annotation : annotations) {
      if (annotation instanceof ActionParameterDescription) {
        return (ActionParameterDescription)annotation;
      }
    }
    return null;
  }

  /**
   * Checks if is action parameter description necessary.
   *
   * @param parameterType the parameter type
   * @param index the index
   * @return true, if is action parameter description necessary
   */
  protected boolean isActionParameterDescriptionNecessary(Class parameterType, int index) {
    return true;
  }

  /**
   * Checks if is service method.
   *
   * @param method the method
   * @return true, if is service method
   */
  protected boolean isServiceMethod(Method method) {
    return method.isAnnotationPresent(ActionDescription.class);
  }

  /**
   * Read name.
   *
   * @param method the method
   * @param actionDescription the action description
   * @return the string
   */
  private String readName(Method method, ActionDescription actionDescription) {
    return StringUtils.isNotBlank(actionDescription.methodName()) ? actionDescription.methodName() : method.getName();
  }

  /**
   * Read parameter.
   *
   * @param method the method
   * @return the list
   */
  private List readParameter(Method method) {
    // 1.8 nötig
    final Class[] parameters = method.getParameterTypes();
    final Annotation[][] parameterAnnotations = method.getParameterAnnotations();
    final List toReturn = new ArrayList<>(parameters.length);
    for (int i = 0; i < parameters.length; i++) {
      final InputParameterDescription inputParameterDescription = this.createInputParameterDescription(parameters[i], parameterAnnotations[i], i);
      if (inputParameterDescription != null) {
        toReturn.add(inputParameterDescription);
      }
    }
    return toReturn;
  }
}