Cleaned up Java Binding code from YANG Tools

[mdsal.git] / binding / yang-binding / src / main / java / org / opendaylight / yangtools / yang / binding / util / AugmentationFieldGetter.java

diff --git a/binding/yang-binding/src/main/java/org/opendaylight/yangtools/yang/binding/util/AugmentationFieldGetter.java b/binding/yang-binding/src/main/java/org/opendaylight/yangtools/yang/binding/util/AugmentationFieldGetter.java
new file mode 100644 (file)
index 0000000..9347685
--- /dev/null
+++ b/binding/yang-binding/src/main/java/org/opendaylight/yangtools/yang/binding/util/AugmentationFieldGetter.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.yangtools.yang.binding.util;
+
+import org.opendaylight.yangtools.yang.binding.AugmentationHolder;
+
+import com.google.common.base.Preconditions;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import java.lang.reflect.Field;
+import java.util.Collections;
+import java.util.Map;
+import org.opendaylight.yangtools.yang.binding.Augmentation;
+import org.opendaylight.yangtools.yang.binding.BindingMapping;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+abstract class AugmentationFieldGetter {
+
+    private static final Logger LOG = LoggerFactory.getLogger(AugmentationFieldGetter.class);
+
+    private static final AugmentationFieldGetter DUMMY = new AugmentationFieldGetter() {
+        @Override
+        protected Map<Class<? extends Augmentation<?>>, Augmentation<?>> getAugmentations(final Object input) {
+            return Collections.emptyMap();
+        }
+    };
+
+    private static final AugmentationFieldGetter AUGMENTATION_HOLDER_GETTER = new AugmentationFieldGetter() {
+
+        @Override
+        @SuppressWarnings({"unchecked", "rawtypes"})
+        protected Map<Class<? extends Augmentation<?>>, Augmentation<?>> getAugmentations(final Object input) {
+            return (Map) ((AugmentationHolder<?>) input).augmentations();
+        }
+    };
+
+    /**
+     *
+     * Retrieves augmentations from supplied object
+     *
+     * @param input Input Data object, from which augmentations should be extracted
+     * @return Map of Augmentation class to augmentation
+     */
+    protected abstract Map<Class<? extends Augmentation<?>>, Augmentation<?>> getAugmentations(final Object input);
+
+    private static final LoadingCache<Class<?>, AugmentationFieldGetter> AUGMENTATION_GETTERS = CacheBuilder
+            .newBuilder().weakKeys().softValues().build(new AugmentationGetterLoader());
+
+    public static AugmentationFieldGetter getGetter(final Class<? extends Object> clz) {
+        if(AugmentationHolder.class.isAssignableFrom(clz)) {
+            return AUGMENTATION_HOLDER_GETTER;
+        }
+        return AUGMENTATION_GETTERS.getUnchecked(clz);
+    }
+
+    private static final class AugmentationGetterLoader extends CacheLoader<Class<?>, AugmentationFieldGetter> {
+
+        @Override
+        public AugmentationFieldGetter load(final Class<?> key) throws Exception {
+            Field field;
+            try {
+                field = key.getDeclaredField(BindingMapping.AUGMENTATION_FIELD);
+            } catch (NoSuchFieldException | SecurityException e) {
+                LOG.debug("Failed to acquire augmentation field", e);
+                return DUMMY;
+            }
+            field.setAccessible(true);
+
+            return new ReflectionAugmentationFieldGetter(field);
+        }
+    }
+
+    private static final class ReflectionAugmentationFieldGetter extends AugmentationFieldGetter {
+        private final Field augmentationField;
+
+        ReflectionAugmentationFieldGetter(final Field augmentationField) {
+            this.augmentationField = Preconditions.checkNotNull(augmentationField);
+        }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        protected Map<Class<? extends Augmentation<?>>, Augmentation<?>> getAugmentations(final Object input) {
+            try {
+                return (Map<Class<? extends Augmentation<?>>, Augmentation<?>>) augmentationField.get(input);
+            } catch (IllegalArgumentException | IllegalAccessException e) {
+                throw new IllegalStateException("Failed to access augmentation field", e);
+            }
+        }
+    }
+
+}