mv com/google/domain/registry google/registry

This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.

java/google/registry/mapreduce/inputs/ChunkingKeyInput.java

@@ -0,0 +1,113 @@
+// Copyright 2016 The Domain Registry 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 com.google.domain.registry.mapreduce.inputs;
+
+import com.google.appengine.api.datastore.Key;
+import com.google.appengine.tools.mapreduce.Input;
+import com.google.appengine.tools.mapreduce.InputReader;
+import com.google.common.collect.ImmutableList;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+/** A MapReduce {@link Input} adapter that chunks an input of keys into sublists of keys. */
+public class ChunkingKeyInput extends Input<List<Key>> {
+
+  private static final long serialVersionUID = 1670202385246824694L;
+
+  private final Input<Key> input;
+  private final int chunkSize;
+
+  public ChunkingKeyInput(Input<Key> input, int chunkSize) {
+    this.input = input;
+    this.chunkSize = chunkSize;
+  }
+
+  /**
+   * An input reader that wraps around another input reader and returns its contents in chunks of
+   * a given size.
+   */
+  private static class ChunkingKeyInputReader extends InputReader<List<Key>> {
+
+    private static final long serialVersionUID = 53502324675703263L;
+
+    private final InputReader<Key> reader;
+    private final int chunkSize;
+
+    ChunkingKeyInputReader(InputReader<Key> reader, int chunkSize) {
+      this.reader = reader;
+      this.chunkSize = chunkSize;
+    }
+
+    @Override
+    public List<Key> next() throws IOException {
+      ImmutableList.Builder<Key> chunk = new ImmutableList.Builder<>();
+      try {
+        for (int i = 0; i < chunkSize; i++) {
+          chunk.add(reader.next());
+        }
+      } catch (NoSuchElementException e) {
+        // Amazingly this is the recommended (and only) way to test for hasNext().
+      }
+      ImmutableList<Key> builtChunk = chunk.build();
+      if (builtChunk.isEmpty()) {
+        throw new NoSuchElementException();  // Maintain the contract.
+      }
+      return builtChunk;
+    }
+
+    @Override
+    public Double getProgress() {
+      return reader.getProgress();
+    }
+
+    @Override
+    public void beginShard() throws IOException {
+      reader.beginShard();
+    }
+
+    @Override
+    public void beginSlice() throws IOException {
+      reader.beginSlice();
+    }
+
+    @Override
+    public void endSlice() throws IOException {
+      reader.endSlice();
+    }
+
+    @Override
+    public void endShard() throws IOException {
+      reader.endShard();
+    }
+
+    @Override
+    public long estimateMemoryRequirement() {
+      // The reader's memory requirement plus the memory for this chunk's worth of buffered keys.
+      // 256 comes from DatastoreKeyInputReader.AVERAGE_KEY_SIZE.
+      return reader.estimateMemoryRequirement() + chunkSize * 256;
+    }
+  }
+
+  @Override
+  public List<InputReader<List<Key>>> createReaders() throws IOException {
+    ImmutableList.Builder<InputReader<List<Key>>> readers = new ImmutableList.Builder<>();
+    for (InputReader<Key> reader : input.createReaders()) {
+      readers.add(new ChunkingKeyInputReader(reader, chunkSize));
+    }
+    return readers.build();
+  }
+}