/**
* 获取与name相对应的统计数据
*
* @param application
* @param name
* @param startTime 开始时间(毫秒)
* @param endTime 结束时间(毫秒)
* @param step 取样间隔(秒)
*/
public static List<Data<Long, Double>> getDataList(
String application, String name, long startTime, long endTime, long step) {
File rrdFile = getStorageRrdFile(application, name);
if (!rrdFile.exists()) {
return Collections.emptyList();
}
try {
String dsName = name;
if (dsName.length() > 20) { // 貌似是melody中的机制
dsName = dsName.substring(0, 20);
}
DataProcessor processor = new DataProcessor(startTime / 1000, endTime / 1000);
processor.addDatasource("average", rrdFile.getAbsolutePath(), dsName, "AVERAGE");
processor.setStep(step);
// poolUsed设为true，会使用read_write模式，
// 只有这样，打开rrd文件和调用fileChannel.map方法时的读写模式才会前后一致
processor.setPoolUsed(true);
processor.processData();
double[] values = processor.getValues("average");
long[] timestamps = processor.getTimestamps();
assert values.length == timestamps.length;
List<Data<Long, Double>> dataList = Lists.newArrayList();
for (int i = 0, l = timestamps.length; i < l; i++) {
dataList.add(
new Data<Long, Double>()
.key(timestamps[i] * 1000)
.value(Double.isNaN(values[i]) ? 0D : values[i]));
}
return dataList;
} catch (Exception e) {
e.printStackTrace();
return Collections.emptyList();
}
}
