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 edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  14 import java.lang.reflect.Method;
  15 import org.eclipse.jdt.annotation.NonNull;
  16 import org.eclipse.jdt.annotation.Nullable;
  17 import org.opendaylight.yangtools.yang.binding.DataObject;
  18 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
  19 import org.opendaylight.yangtools.yang.binding.annotations.RoutingContext;
  20 import org.slf4j.Logger;
  21 import org.slf4j.LoggerFactory;
  22
  23 abstract class ContextReferenceExtractor {
  24
  25     private static final Logger LOG = LoggerFactory.getLogger(ContextReferenceExtractor.class);
  26     private static final ContextReferenceExtractor NULL_EXTRACTOR = new ContextReferenceExtractor() {
  27
  28         @Override
  29         InstanceIdentifier<?> extract(final DataObject obj) {
  30             return null;
  31         }
  32     };
  33
  34     private static final LoadingCache<Class<?>, ContextReferenceExtractor> EXTRACTORS = CacheBuilder.newBuilder()
  35             .weakKeys().build(new CacheLoader<Class<?>, ContextReferenceExtractor>() {
  36
  37                 @Override
  38                 public ContextReferenceExtractor load(final Class<?> key) throws Exception {
  39                     return create(key);
  40                 }
  41
  42                 private @NonNull ContextReferenceExtractor create(final Class<?> key) {
  43                     final Method contextGetter = getContextGetter(key);
  44                     if (contextGetter == null) {
  45                         return NULL_EXTRACTOR;
  46                     }
  47                     final Class<?> returnType = contextGetter.getReturnType();
  48                     try {
  49                         if (InstanceIdentifier.class.isAssignableFrom(returnType)) {
  50                             return DirectGetterRouteContextExtractor.create(contextGetter);
  51                         }
  52                         final Method getValueMethod = findGetValueMethod(returnType, InstanceIdentifier.class);
  53                         if (getValueMethod != null) {
  54                             return GetValueRouteContextExtractor.create(contextGetter, getValueMethod);
  55                         } else {
  56                             LOG.warn("Class {} can not be used to determine context, falling back to NULL_EXTRACTOR.",
  57                                     returnType);
  58                         }
  59                     } catch (final IllegalAccessException e) {
  60                         LOG.warn(
  61                                 "Class {} does not conform to Binding Specification v1. Falling back to NULL_EXTRACTOR",
  62                                 returnType, e);
  63                     }
  64                     return NULL_EXTRACTOR;
  65                 }
  66
  67                 private Method getContextGetter(final Class<?> key) {
  68                     for (final Method method : key.getMethods()) {
  69                         if (method.getAnnotation(RoutingContext.class) != null) {
  70                             return method;
  71                         }
  72                     }
  73                     return null;
  74                 }
  75             });
  76
  77
  78     private static final String GET_VALUE_NAME = "getValue";
  79
  80     static ContextReferenceExtractor from(final Class<?> obj) {
  81         return EXTRACTORS.getUnchecked(obj);
  82     }
  83
  84     /**
  85      * Extract context-reference (Instance Identifier) from a Binding DataObject.
  86      *
  87      * @param obj DataObject from which context reference should be extracted.
  88      *
  89      * @return Instance Identifier representing context reference or null, if data object does not contain a context
  90      *         reference.
  91      */
  92     abstract @Nullable InstanceIdentifier<?> extract(DataObject obj);
  93
  94     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
  95             justification = "https://github.com/spotbugs/spotbugs/issues/811")
  96     private static @Nullable Method findGetValueMethod(final Class<?> type, final Class<?> returnType) {
  97         try {
  98             final Method method = type.getMethod(GET_VALUE_NAME);
  99             if (returnType.equals(method.getReturnType())) {
 100                 return method;
 101             }
 102         } catch (final NoSuchMethodException e) {
 103             LOG.warn("Value class {} does not comform to Binding Specification v1.", type, e);
 104         }
 105         return null;
 106     }
 107 }