| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.mapred.nativetask; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * Any key type that is comparable at native side must implement this interface. |
| * |
| * A native comparator function should have the ComparatorPtr type: |
| * <code> |
| * typedef int (*ComparatorPtr)(const char * src, uint32_t srcLength, |
| * const char * dest, uint32_t destLength); |
| * </code> |
| * Keys are in serialized format at native side. The function has passed in |
| * the keys' locations and lengths such that we can compare them in the same |
| * logic as their Java comparator. |
| * |
| * For example, a HiveKey serialized as an int field (containing the length of |
| * raw bytes) + raw bytes. |
| * When comparing two HiveKeys, we first read the length field and then |
| * compare the raw bytes by invoking the BytesComparator provided by our library. |
| * We pass the location and length of raw bytes into BytesComparator. |
| * |
| * <code> |
| * int HivePlatform::HiveKeyComparator(const char * src, uint32_t srcLength, |
| * const char * dest, uint32_t destLength) { |
| * uint32_t sl = bswap(*(uint32_t*)src); |
| * uint32_t dl = bswap(*(uint32_t*)dest); |
| * return NativeObjectFactory::BytesComparator(src + 4, sl, dest + 4, dl); |
| * } |
| * </code> |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| public interface INativeComparable { |
| } |
