binding/mdsal-binding-dom-adapter/src/main/java/org/opendaylight/mdsal/binding/dom/adapter/ContextReferenceExtractor.java

   1 /*
   2  * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.mdsal.binding.dom.adapter;
   9
  10 import com.google.common.cache.CacheBuilder;
  11 import com.google.common.cache.CacheLoader;
  12 import com.google.common.cache.LoadingCache;
  13 import java.lang.reflect.Method;
  14 import org.eclipse.jdt.annotation.NonNull;
  15 import org.eclipse.jdt.annotation.Nullable;
  16 import org.opendaylight.yangtools.yang.binding.DataObject;
  17 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
  18 import org.opendaylight.yangtools.yang.binding.annotations.RoutingContext;
  19 import org.slf4j.Logger;
  20 import org.slf4j.LoggerFactory;
  21
  22 abstract class ContextReferenceExtractor {
  23
  24     private static final Logger LOG = LoggerFactory.getLogger(ContextReferenceExtractor.class);
  25     private static final ContextReferenceExtractor NULL_EXTRACTOR = new ContextReferenceExtractor() {
  26
  27         @Override
  28         InstanceIdentifier<?> extract(final DataObject obj) {
  29             return null;
  30         }
  31     };
  32
  33     private static final LoadingCache<Class<?>, ContextReferenceExtractor> EXTRACTORS = CacheBuilder.newBuilder()
  34             .weakKeys().build(new CacheLoader<Class<?>, ContextReferenceExtractor>() {
  35
  36                 @Override
  37                 public ContextReferenceExtractor load(final Class<?> key) throws Exception {
  38                     return create(key);
  39                 }
  40
  41                 private @NonNull ContextReferenceExtractor create(final Class<?> key) {
  42                     final Method contextGetter = getContextGetter(key);
  43                     if (contextGetter == null) {
  44                         return NULL_EXTRACTOR;
  45                     }
  46                     final Class<?> returnType = contextGetter.getReturnType();
  47                     try {
  48                         if (InstanceIdentifier.class.isAssignableFrom(returnType)) {
  49                             return DirectGetterRouteContextExtractor.create(contextGetter);
  50                         }
  51                         final Method getValueMethod = findGetValueMethod(returnType, InstanceIdentifier.class);
  52                         if (getValueMethod != null) {
  53                             return GetValueRouteContextExtractor.create(contextGetter, getValueMethod);
  54                         } else {
  55                             LOG.warn("Class {} can not be used to determine context, falling back to NULL_EXTRACTOR.",
  56                                     returnType);
  57                         }
  58                     } catch (final IllegalAccessException e) {
  59                         LOG.warn(
  60                                 "Class {} does not conform to Binding Specification v1. Falling back to NULL_EXTRACTOR",
  61                                 returnType, e);
  62                     }
  63                     return NULL_EXTRACTOR;
  64                 }
  65
  66                 private Method getContextGetter(final Class<?> key) {
  67                     for (final Method method : key.getMethods()) {
  68                         if (method.getAnnotation(RoutingContext.class) != null) {
  69                             return method;
  70                         }
  71                     }
  72                     return null;
  73                 }
  74             });
  75
  76
  77     private static final String GET_VALUE_NAME = "getValue";
  78
  79     static ContextReferenceExtractor from(final Class<?> obj) {
  80         return EXTRACTORS.getUnchecked(obj);
  81     }
  82
  83     /**
  84      * Extract context-reference (Instance Identifier) from a Binding DataObject.
  85      *
  86      * @param obj DataObject from which context reference should be extracted.
  87      *
  88      * @return Instance Identifier representing context reference or null, if data object does not contain a context
  89      *         reference.
  90      */
  91     abstract @Nullable InstanceIdentifier<?> extract(DataObject obj);
  92
  93     private static @Nullable Method findGetValueMethod(final Class<?> type, final Class<?> returnType) {
  94         try {
  95             final Method method = type.getMethod(GET_VALUE_NAME);
  96             if (returnType.equals(method.getReturnType())) {
  97                 return method;
  98             }
  99         } catch (final NoSuchMethodException e) {
 100             LOG.warn("Value class {} does not comform to Binding Specification v1.", type, e);
 101         }
 102         return null;
 103     }
 104 }