Add MapReduce Input for CommitLogManifest

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159749707

java/google/registry/mapreduce/inputs/CommitLogManifestInput.java

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+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.mapreduce.inputs;
+
+import com.google.appengine.tools.mapreduce.Input;
+import com.google.appengine.tools.mapreduce.InputReader;
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableList;
+import com.googlecode.objectify.Key;
+import google.registry.model.ofy.CommitLogBucket;
+import google.registry.model.ofy.CommitLogManifest;
+import java.util.List;
+import org.joda.time.DateTime;
+
+/** Base class for {@link Input} classes that map over {@link CommitLogManifest}. */
+public class CommitLogManifestInput extends Input<CommitLogManifest> {
+
+  private static final long serialVersionUID = 2043552272352286428L;
+
+  /**
+   * Cutoff date for result.
+   *
+   * If present, all resulting CommitLogManifest will be dated prior to this date.
+   */
+  private final Optional<DateTime> olderThan;
+
+  public CommitLogManifestInput(Optional<DateTime> olderThan) {
+    this.olderThan = olderThan;
+  }
+
+  @Override
+  public List<InputReader<CommitLogManifest>> createReaders() {
+    ImmutableList.Builder<InputReader<CommitLogManifest>> readers = new ImmutableList.Builder<>();
+    for (Key<CommitLogBucket> bucketKey : CommitLogBucket.getAllBucketKeys()) {
+      readers.add(bucketToReader(bucketKey));
+    }
+    return readers.build();
+  }
+
+  private InputReader<CommitLogManifest> bucketToReader(Key<CommitLogBucket> bucketKey) {
+    return new CommitLogManifestReader(bucketKey, olderThan);
+  }
+}