/*
* Copyright 2014 NAVER Corp.
*
* 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.navercorp.pinpoint.common.hbase;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.springframework.util.Assert;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
/**
* @author emeroad
*/
public class LimitRowMapperResultsExtractor<T> implements ResultsExtractor<List<T>> {
private static final LimitEventHandler EMPTY = new EmptyLimitEventHandler();
private int limit = Integer.MAX_VALUE;
private final RowMapper<T> rowMapper;
private LimitEventHandler eventHandler;
public int getLimit() {
return limit;
}
public void setLimit(int limit) {
this.limit = limit;
}
/**
* Create a new RowMapperResultSetExtractor.
*
* @param rowMapper the RowMapper which creates an object for each row
*/
public LimitRowMapperResultsExtractor(RowMapper<T> rowMapper, int limit) {
this(rowMapper, limit, EMPTY);
}
/**
* Create a new RowMapperResultSetExtractor.
*
* @param rowMapper the RowMapper which creates an object for each row
*/
public LimitRowMapperResultsExtractor(RowMapper<T> rowMapper, int limit, LimitEventHandler eventHandler) {
Assert.notNull(rowMapper, "RowMapper is required");
Assert.notNull(eventHandler, "LimitEventHandler is required");
this.rowMapper = rowMapper;
this.limit = limit;
this.eventHandler = eventHandler;
}
public List<T> extractData(ResultScanner results) throws Exception {
final List<T> rs = new ArrayList<>();
int rowNum = 0;
Result lastResult = null;
for (Result result : results) {
final T t = this.rowMapper.mapRow(result, rowNum);
lastResult = result;
if (t instanceof Collection) {
rowNum += ((Collection<?>) t).size();
} else if (t instanceof Map) {
rowNum += ((Map<?, ?>) t).size();
} else if (t == null) {
// empty
} else if (t.getClass().isArray()) {
rowNum += Array.getLength(t);
} else {
rowNum++;
}
rs.add(t);
if (rowNum >= limit) {
break;
}
}
eventHandler.handleLastResult(lastResult);
return rs;
}
}