1 files changed, 90 insertions, 0 deletions
diff --git a/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/AbstractGenericReader.java b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/AbstractGenericReader.java
new file mode 100644
index 000000000..75a2a673c
--- /dev/null
+++ b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/AbstractGenericReader.java
@@ -0,0 +1,90 @@
+/*
+ * 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.translate.util.read;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.annotations.Beta;
+import com.google.common.base.Optional;
+import io.fd.honeycomb.translate.read.ReadContext;
+import io.fd.honeycomb.translate.read.Reader;
+import io.fd.honeycomb.translate.util.RWUtils;
+import io.fd.honeycomb.translate.read.ReadFailedException;
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Beta
+public abstract class AbstractGenericReader<D extends DataObject, B extends Builder<D>> implements Reader<D, B> {
+
+    private static final Logger LOG = LoggerFactory.getLogger(AbstractGenericReader.class);
+
+    private final InstanceIdentifier<D> instanceIdentifier;
+
+    protected AbstractGenericReader(final InstanceIdentifier<D> managedDataObjectType) {
+        this.instanceIdentifier = RWUtils.makeIidWildcarded(managedDataObjectType);
+    }
+
+    @Nonnull
+    @Override
+    public final InstanceIdentifier<D> getManagedDataObjectType() {
+        return instanceIdentifier;
+    }
+
+    /**
+     * @param id {@link InstanceIdentifier} pointing to current node. In case of keyed list, key must be present.
+     *
+     */
+    protected Optional<D> readCurrent(@Nonnull final InstanceIdentifier<D> id,
+                                      @Nonnull final ReadContext ctx) throws ReadFailedException {
+        LOG.debug("{}: Reading current: {}", this, id);
+        final B builder = getBuilder(id);
+        // Cache empty value to determine if anything has changed later TODO cache in a field
+        final D emptyValue = builder.build();
+
+        LOG.trace("{}: Reading current attributes", this);
+        readCurrentAttributes(id, builder, ctx);
+
+        // Need to check whether anything was filled in to determine if data is present or not.
+        final D built = builder.build();
+        final Optional<D> read = built.equals(emptyValue)
+            ? Optional.absent()
+            : Optional.of(built);
+
+        LOG.debug("{}: Current node read successfully. Result: {}", this, read);
+        return read;
+    }
+
+    @Nonnull
+    @Override
+    @SuppressWarnings("unchecked")
+    public Optional<? extends DataObject> read(@Nonnull final InstanceIdentifier<? extends DataObject> id,
+                                               @Nonnull final ReadContext ctx)
+            throws ReadFailedException {
+        LOG.trace("{}: Reading : {}", this, id);
+        checkArgument(id.getTargetType().equals(getManagedDataObjectType().getTargetType()));
+        return readCurrent((InstanceIdentifier<D>) id, ctx);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("Reader[%s]", getManagedDataObjectType().getTargetType().getSimpleName());
+    }
+}