catalog-be/src/main/java/org/openecomp/sdc/be/view/MixinModelWriter.java

   1 package org.openecomp.sdc.be.view;
   2
   3 import com.fasterxml.jackson.databind.ObjectMapper;
   4 import com.fasterxml.jackson.databind.SerializationFeature;
   5
   6 import javax.ws.rs.Produces;
   7 import javax.ws.rs.core.MediaType;
   8 import javax.ws.rs.core.MultivaluedMap;
   9 import javax.ws.rs.ext.MessageBodyWriter;
  10 import javax.ws.rs.ext.Provider;
  11 import java.io.IOException;
  12 import java.io.OutputStream;
  13 import java.lang.annotation.Annotation;
  14 import java.lang.reflect.Type;
  15 import java.util.List;
  16 import java.util.Objects;
  17 import java.util.stream.Collectors;
  18 import java.util.stream.Stream;
  19
  20 /**
  21  * A class that is then responsible for converting a message payload with a dedicated mixin from an instance of a specific Java type into a json representation.
  22  */
  23 @Provider
  24 @Produces(MediaType.APPLICATION_JSON)
  25 public class MixinModelWriter implements MessageBodyWriter<Object> {
  26
  27     @Override
  28     public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
  29         return hasResponseViewAndMixinTargetAnnotations(annotations) && mediaType.isCompatible(MediaType.APPLICATION_JSON_TYPE);
  30     }
  31
  32     @Override
  33     public long getSize(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
  34         return -1;
  35     }
  36
  37     @Override
  38     public void writeTo(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException {
  39         ObjectMapper objectMapper = new ObjectMapper();
  40         objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
  41         List<MixinSourceTarget> mixinSourceTargets = getMixinSourceTarget(annotations);
  42         mixinSourceTargets.forEach(mixinSourceTarget -> objectMapper.addMixIn(mixinSourceTarget.getTarget(), mixinSourceTarget.getMixinSource()));
  43         objectMapper.writeValue(entityStream, object);
  44     }
  45
  46     private List<MixinSourceTarget> getMixinSourceTarget(Annotation[] annotations) {
  47         return Stream.of(annotations)
  48                 .filter(annotation -> annotation.annotationType().equals(ResponseView.class))
  49                 .map(annotation -> (ResponseView) annotation)
  50                 .flatMap(responseView -> Stream.of(responseView.mixin()))
  51                 .map(mixinClass -> new MixinSourceTarget(mixinClass, mixinClass.getAnnotation(MixinTarget.class).target()))
  52                 .collect(Collectors.toList());
  53     }
  54
  55     private boolean hasResponseViewAndMixinTargetAnnotations(Annotation[] annotations) {
  56         return Stream.of(annotations)
  57                 .filter(annotation -> annotation.annotationType().equals(ResponseView.class))
  58                 .map(annotation -> (ResponseView) annotation)
  59                 .flatMap(responseView -> Stream.of(responseView.mixin()))
  60                 .anyMatch(mixinClass -> Objects.nonNull(mixinClass.getAnnotation(MixinTarget.class)));
  61     }
  62 }