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