1 files changed, 82 insertions, 0 deletions
diff --git a/v3po/impl/src/main/java/io/fd/honeycomb/v3po/impl/trans/r/util/DelegatingReaderRegistry.java b/v3po/impl/src/main/java/io/fd/honeycomb/v3po/impl/trans/r/util/DelegatingReaderRegistry.java
new file mode 100644
index 000000000..9e672c92f
--- /dev/null
+++ b/v3po/impl/src/main/java/io/fd/honeycomb/v3po/impl/trans/r/util/DelegatingReaderRegistry.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.v3po.impl.trans.r.util;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.Iterables;
+import io.fd.honeycomb.v3po.impl.trans.r.ReaderRegistry;
+import io.fd.honeycomb.v3po.impl.trans.r.VppReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+/**
+ * Simple reader registry able to perform and aggregated read (ROOT read) on top of all
+ * provided readers. Also able to delegate a specific read to one of the delegate readers.
+ *
+ * This could serve as a utility to hold & hide all available readers in upper layers.
+ */
+public final class DelegatingReaderRegistry implements ReaderRegistry {
+
+    private final Map<Class<? extends DataObject>, VppReader<? extends DataObject>> rootReaders;
+
+    /**
+     * Create new {@link DelegatingReaderRegistry}
+     *
+     * @param rootReaders List of delegate readers
+     */
+    public DelegatingReaderRegistry(@Nonnull final List<VppReader<? extends DataObject>> rootReaders) {
+        this.rootReaders = VppRWUtils.uniqueLinkedIndex(checkNotNull(rootReaders), VppRWUtils.MANAGER_CLASS_FUNCTION);
+    }
+
+    @Override
+    @Nonnull
+    public List<? extends DataObject> readAll() {
+        final List<DataObject> objects = new ArrayList<>(rootReaders.size());
+        for (VppReader<? extends DataObject> rootReader : rootReaders.values()) {
+            final List<? extends DataObject> read = rootReader.read(rootReader.getManagedDataObjectType());
+            objects.addAll(read);
+        }
+        return objects;
+    }
+
+    @Nonnull
+    @Override
+    public List<? extends DataObject> read(@Nonnull final InstanceIdentifier<? extends DataObject> id) {
+        final InstanceIdentifier.PathArgument first = checkNotNull(
+            Iterables.getFirst(id.getPathArguments(), null), "Empty id");
+        final VppReader<? extends DataObject> vppReader = rootReaders.get(first.getType());
+        checkNotNull(vppReader,
+            "Unable to read %s. Missing reader. Current readers for: %s", id, rootReaders.keySet());
+        return vppReader.read(id);
+    }
+
+    /**
+     * @throws UnsupportedOperationException This getter is not supported for reader registry since it does not manage a
+     *                                       specific node type
+     */
+    @Nonnull
+    @Override
+    public InstanceIdentifier<DataObject> getManagedDataObjectType() {
+        throw new UnsupportedOperationException("Root registry has no type");
+    }
+
+}