| /** |
| * 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.hbase.client; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.yetus.audience.InterfaceAudience; |
| import org.apache.hadoop.hbase.util.Bytes; |
| |
| /** |
| * A scan result cache that only returns complete result. |
| */ |
| @InterfaceAudience.Private |
| class CompleteScanResultCache implements ScanResultCache { |
| |
| private int numberOfCompleteRows; |
| |
| private final List<Result> partialResults = new ArrayList<>(); |
| |
| private Result combine() throws IOException { |
| Result result = Result.createCompleteResult(partialResults); |
| partialResults.clear(); |
| return result; |
| } |
| |
| private Result[] prependCombined(Result[] results, int length) throws IOException { |
| if (length == 0) { |
| return new Result[] { combine() }; |
| } |
| // the last part of a partial result may not be marked as partial so here we need to check if |
| // there is a row change. |
| int start; |
| if (Bytes.equals(partialResults.get(0).getRow(), results[0].getRow())) { |
| partialResults.add(results[0]); |
| start = 1; |
| length--; |
| } else { |
| start = 0; |
| } |
| Result[] prependResults = new Result[length + 1]; |
| prependResults[0] = combine(); |
| System.arraycopy(results, start, prependResults, 1, length); |
| return prependResults; |
| } |
| |
| private Result[] updateNumberOfCompleteResultsAndReturn(Result... results) { |
| numberOfCompleteRows += results.length; |
| return results; |
| } |
| |
| @Override |
| public Result[] addAndGet(Result[] results, boolean isHeartbeatMessage) throws IOException { |
| // If no results were returned it indicates that either we have the all the partial results |
| // necessary to construct the complete result or the server had to send a heartbeat message |
| // to the client to keep the client-server connection alive |
| if (results.length == 0) { |
| // If this response was an empty heartbeat message, then we have not exhausted the region |
| // and thus there may be more partials server side that still need to be added to the partial |
| // list before we form the complete Result |
| if (!partialResults.isEmpty() && !isHeartbeatMessage) { |
| return updateNumberOfCompleteResultsAndReturn(combine()); |
| } |
| return EMPTY_RESULT_ARRAY; |
| } |
| // In every RPC response there should be at most a single partial result. Furthermore, if |
| // there is a partial result, it is guaranteed to be in the last position of the array. |
| Result last = results[results.length - 1]; |
| if (last.mayHaveMoreCellsInRow()) { |
| if (partialResults.isEmpty()) { |
| partialResults.add(last); |
| return updateNumberOfCompleteResultsAndReturn(Arrays.copyOf(results, results.length - 1)); |
| } |
| // We have only one result and it is partial |
| if (results.length == 1) { |
| // check if there is a row change |
| if (Bytes.equals(partialResults.get(0).getRow(), last.getRow())) { |
| partialResults.add(last); |
| return EMPTY_RESULT_ARRAY; |
| } |
| Result completeResult = combine(); |
| partialResults.add(last); |
| return updateNumberOfCompleteResultsAndReturn(completeResult); |
| } |
| // We have some complete results |
| Result[] resultsToReturn = prependCombined(results, results.length - 1); |
| partialResults.add(last); |
| return updateNumberOfCompleteResultsAndReturn(resultsToReturn); |
| } |
| if (!partialResults.isEmpty()) { |
| return updateNumberOfCompleteResultsAndReturn(prependCombined(results, results.length)); |
| } |
| return updateNumberOfCompleteResultsAndReturn(results); |
| } |
| |
| @Override |
| public void clear() { |
| partialResults.clear(); |
| } |
| |
| @Override |
| public int numberOfCompleteRows() { |
| return numberOfCompleteRows; |
| } |
| } |