Java tutorial
/* * The MIT License * * Copyright 2016 cambierr. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.github.lynxdb.server.core; import com.github.lynxdb.server.common.ChainableIterator; import com.github.lynxdb.server.common.SuperIterator; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import org.springframework.util.Assert; /** * * @author cambierr */ public abstract class Aggregator { public abstract TimeSerie aggregate(List<TimeSerie> _series); public abstract TimeSerie downsample(TimeSerie _serie, long _period); protected TimeSerie doDownsampling(TimeSerie _serie, long _period, Reducer _reducer) { return new TimeSerie(_serie.getName(), _serie.getTags(), new ChainableIterator<Entry>() { int lower; Entry last = null; @Override public boolean hasNext() { return _serie.hasNext() || last != null; } @Override public Entry next() { _reducer.reset(); if (last == null) { Entry e = _serie.next(); lower = (int) (_period * Math.floorDiv(e.getTime(), _period)); _reducer.update(e); } else { lower = (int) (_period * Math.floorDiv(last.getTime(), _period)); _reducer.update(last); last = null; } while (_serie.hasNext()) { last = _serie.next(); if (last.getTime() > lower) { _reducer.update(last); } else { break; } } return new Entry(lower, _reducer.result()); } }); } protected TimeSerie doInterpolate(List<TimeSerie> _series, Reducer _reducer) { Assert.notEmpty(_series); List<SuperIterator> sil = new ArrayList<>(); _series.forEach((TimeSerie t) -> { if (t.hasNext()) { SuperIterator<Entry> si = new SuperIterator<>(t); si.next(); sil.add(si); } }); Map<String, String> tags = new HashMap<>(); tags.putAll(_series.get(0).getTags()); _series.forEach((TimeSerie t) -> { Iterator<Map.Entry<String, String>> i = tags.entrySet().iterator(); while (i.hasNext()) { Map.Entry<String, String> e = i.next(); if (!t.getTags().containsKey(e.getKey()) || !t.getTags().get(e.getKey()).equals(e.getValue())) { i.remove(); } } }); return new TimeSerie(_series.get(0).getName(), tags, new ChainableIterator<Entry>() { @Override public boolean hasNext() { return sil.stream().anyMatch((SuperIterator t) -> t.hasNext() || t.getCurrent() != null); } @Override public Entry next() { _reducer.reset(); Iterator<SuperIterator> rr = sil.iterator(); while (rr.hasNext()) { if (rr.next().getCurrent() == null) { rr.remove(); } } int max = Integer.MIN_VALUE; for (SuperIterator<Entry> r : sil) { max = Integer.max(max, r.getCurrent().getTime()); } for (SuperIterator<Entry> r : sil) { if (r.getCurrent().getTime() == max) { _reducer.update(r.getCurrent()); r.next(); } else if (r.getPrevious() != null) { _reducer.update(new Entry(max, interpolate(r.getCurrent(), r.getPrevious(), max))); } } return new Entry(max, _reducer.result()); } }); } protected TimeSerie doDefaultIfMissing(List<TimeSerie> _series, Reducer _reducer, double _default) { Assert.notEmpty(_series); List<SuperIterator> sil = new ArrayList<>(); _series.forEach((TimeSerie t) -> { if (t.hasNext()) { SuperIterator<Entry> si = new SuperIterator<>(t); si.next(); sil.add(si); } }); Map<String, String> tags = new HashMap<>(); tags.putAll(_series.get(0).getTags()); _series.forEach((TimeSerie t) -> { Iterator<Map.Entry<String, String>> i = tags.entrySet().iterator(); while (i.hasNext()) { Map.Entry<String, String> e = i.next(); if (!t.getTags().containsKey(e.getKey()) || !t.getTags().get(e.getKey()).equals(e.getValue())) { i.remove(); } } }); return new TimeSerie(_series.get(0).getName(), tags, new ChainableIterator<Entry>() { @Override public boolean hasNext() { return sil.stream().anyMatch((SuperIterator t) -> t.hasNext() || t.getCurrent() != null); } @Override public Entry next() { _reducer.reset(); Iterator<SuperIterator> rr = sil.iterator(); while (rr.hasNext()) { if (rr.next().getCurrent() == null) { rr.remove(); } } int max = Integer.MIN_VALUE; for (SuperIterator<Entry> r : sil) { max = Integer.max(max, r.getCurrent().getTime()); } for (SuperIterator<Entry> r : sil) { if (r.getCurrent().getTime() == max) { _reducer.update(r.getCurrent()); r.next(); } else if (r.getPrevious() != null) { _reducer.update(new Entry(max, _default)); } } return new Entry(max, _reducer.result()); } }); } private double interpolate(Entry _left, Entry _right, long _time) { return _left.getTime() + (_time - _left.getTime()) * (_right.getValue() - _left.getValue()) / (_right.getTime() - _left.getTime()); } protected TimeSerie doMerge(List<TimeSerie> _series, Reducer _reducer) { TimeSerie merged = TimeSerie.merge(_series); return new TimeSerie(merged.getName(), merged.getTags(), new ChainableIterator<Entry>() { int time; Entry last = null; @Override public boolean hasNext() { return merged.hasNext() || last != null; } @Override public Entry next() { _reducer.reset(); if (last == null) { Entry e = merged.next(); time = e.getTime(); _reducer.update(e); } else { time = last.getTime(); _reducer.update(last); last = null; } while (merged.hasNext()) { last = merged.next(); if (last.getTime() == time) { _reducer.update(last); } else { break; } } return new Entry(time, _reducer.result()); } }); } public abstract String getName(); public static abstract class Reducer { public abstract void update(Entry _entry); public abstract double result(); public abstract void reset(); } }