reorganise some packages

11 files changed, 1023 insertions, 0 deletions

diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/Sampler.java b/spark-common/src/main/java/me/lucko/spark/sampler/Sampler.java
new file mode 100644
index 0000000..1931ca6
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/Sampler.java
@@ -0,0 +1,184 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (C) Albert Pham <http://www.sk89q.com>
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler;
+
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import com.google.gson.stream.JsonWriter;
+
+import me.lucko.spark.sampler.aggregator.DataAggregator;
+import me.lucko.spark.sampler.aggregator.SimpleDataAggregator;
+import me.lucko.spark.sampler.aggregator.TickedDataAggregator;
+import me.lucko.spark.sampler.node.ThreadNode;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.lang.management.ManagementFactory;
+import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * Main sampler class.
+ */
+public class Sampler implements Runnable {
+    private static final AtomicInteger THREAD_ID = new AtomicInteger(0);
+
+    /** The worker pool for inserting stack nodes */
+    private final ScheduledExecutorService workerPool = Executors.newScheduledThreadPool(
+            9, new ThreadFactoryBuilder().setNameFormat("spark-worker-" + THREAD_ID.getAndIncrement() + "-%d").build()
+    );
+
+    /** The main sampling task */
+    private ScheduledFuture<?> task;
+
+    /** The thread management interface for the current JVM */
+    private final ThreadMXBean threadBean = ManagementFactory.getThreadMXBean();
+    /** The instance used to generate thread information for use in sampling */
+    private final ThreadDumper threadDumper;
+    /** Responsible for aggregating and then outputting collected sampling data */
+    private final DataAggregator dataAggregator;
+
+    /** A future to encapsulation the completion of this sampler instance */
+    private final CompletableFuture<Sampler> future = new CompletableFuture<>();
+
+    /** The interval to wait between sampling, in milliseconds */
+    private final int interval;
+    /** The time when sampling first began */
+    private long startTime = -1;
+    /** The unix timestamp (in millis) when this sampler should automatically complete.*/
+    private final long endTime; // -1 for nothing
+    
+    public Sampler(int interval, ThreadDumper threadDumper, ThreadGrouper threadGrouper, long endTime) {
+        this.threadDumper = threadDumper;
+        this.dataAggregator = new SimpleDataAggregator(this.workerPool, threadGrouper, interval);
+        this.interval = interval;
+        this.endTime = endTime;
+    }
+
+    public Sampler(int interval, ThreadDumper threadDumper, ThreadGrouper threadGrouper, long endTime, TickCounter tickCounter, int tickLengthThreshold) {
+        this.threadDumper = threadDumper;
+        this.dataAggregator = new TickedDataAggregator(this.workerPool, tickCounter, threadGrouper, interval, tickLengthThreshold);
+        this.interval = interval;
+        this.endTime = endTime;
+    }
+
+    /**
+     * Starts the sampler.
+     */
+    public void start() {
+        this.startTime = System.currentTimeMillis();
+        this.dataAggregator.start();
+        this.task = workerPool.scheduleAtFixedRate(this, 0, interval, TimeUnit.MILLISECONDS);
+    }
+
+    public long getStartTime() {
+        if (this.startTime == -1) {
+            throw new IllegalStateException("Not yet started");
+        }
+        return this.startTime;
+    }
+
+    public long getEndTime() {
+        return this.endTime;
+    }
+
+    public CompletableFuture<Sampler> getFuture() {
+        return this.future;
+    }
+
+    public void cancel() {
+        task.cancel(false);
+    }
+
+    @Override
+    public void run() {
+        try {
+            if (this.endTime != -1 && this.endTime <= System.currentTimeMillis()) {
+                this.future.complete(this);
+                cancel();
+                return;
+            }
+
+            ThreadInfo[] threadDumps = this.threadDumper.dumpThreads(this.threadBean);
+            for (ThreadInfo threadInfo : threadDumps) {
+                String threadName = threadInfo.getThreadName();
+                StackTraceElement[] stack = threadInfo.getStackTrace();
+
+                if (threadName == null || stack == null) {
+                    continue;
+                }
+
+                this.dataAggregator.insertData(threadName, stack);
+            }
+        } catch (Throwable t) {
+            this.future.completeExceptionally(t);
+            cancel();
+        }
+    }
+
+    private void writeOutput(JsonWriter writer) throws IOException {
+        writer.beginObject();
+
+        writer.name("type").value("sampler");
+        writer.name("threads").beginArray();
+
+        List<Map.Entry<String, ThreadNode>> data = new ArrayList<>(this.dataAggregator.getData().entrySet());
+        data.sort(Map.Entry.comparingByKey());
+
+        for (Map.Entry<String, ThreadNode> entry : data) {
+            writer.beginObject();
+            writer.name("threadName").value(entry.getKey());
+            writer.name("totalTime").value(entry.getValue().getTotalTime());
+            writer.name("rootNode");
+            entry.getValue().serializeTo(writer);
+            writer.endObject();
+        }
+
+        writer.endArray();
+        writer.endObject();
+    }
+
+    public byte[] formCompressedDataPayload() {
+        ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
+        try (Writer writer = new OutputStreamWriter(new GZIPOutputStream(byteOut), StandardCharsets.UTF_8)) {
+            try (JsonWriter jsonWriter = new JsonWriter(writer)) {
+                writeOutput(jsonWriter);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        return byteOut.toByteArray();
+    }
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/SamplerBuilder.java b/spark-common/src/main/java/me/lucko/spark/sampler/SamplerBuilder.java
new file mode 100644
index 0000000..2936c65
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/SamplerBuilder.java
@@ -0,0 +1,82 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Builds {@link Sampler} instances.
+ */
+public class SamplerBuilder {
+
+    private int samplingInterval = 4;
+    private long timeout = -1;
+    private ThreadDumper threadDumper = ThreadDumper.ALL;
+    private ThreadGrouper threadGrouper = ThreadGrouper.BY_NAME;
+
+    private int ticksOver = -1;
+    private TickCounter tickCounter = null;
+
+    public SamplerBuilder() {
+    }
+
+    public SamplerBuilder samplingInterval(int samplingInterval) {
+        this.samplingInterval = samplingInterval;
+        return this;
+    }
+
+    public SamplerBuilder completeAfter(long timeout, TimeUnit unit) {
+        if (timeout <= 0) {
+            throw new IllegalArgumentException("timeout > 0");
+        }
+        this.timeout = System.currentTimeMillis() + unit.toMillis(timeout);
+        return this;
+    }
+
+    public SamplerBuilder threadDumper(ThreadDumper threadDumper) {
+        this.threadDumper = threadDumper;
+        return this;
+    }
+
+    public SamplerBuilder threadGrouper(ThreadGrouper threadGrouper) {
+        this.threadGrouper = threadGrouper;
+        return this;
+    }
+
+    public SamplerBuilder ticksOver(int ticksOver, TickCounter tickCounter) {
+        this.ticksOver = ticksOver;
+        this.tickCounter = tickCounter;
+        return this;
+    }
+
+    public Sampler start() {
+        Sampler sampler;
+        if (this.ticksOver != -1 && this.tickCounter != null) {
+            sampler = new Sampler(this.samplingInterval, this.threadDumper, this.threadGrouper, this.timeout, this.tickCounter, this.ticksOver);
+        } else {
+            sampler = new Sampler(this.samplingInterval, this.threadDumper, this.threadGrouper, this.timeout);
+        }
+
+        sampler.start();
+        return sampler;
+    }
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/ThreadDumper.java b/spark-common/src/main/java/me/lucko/spark/sampler/ThreadDumper.java
new file mode 100644
index 0000000..af963c6
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/ThreadDumper.java
@@ -0,0 +1,80 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (C) Albert Pham <http://www.sk89q.com>
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler;
+
+import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Uses the {@link ThreadMXBean} to generate {@link ThreadInfo} instances for the threads being
+ * sampled.
+ */
+@FunctionalInterface
+public interface ThreadDumper {
+
+    /**
+     * Generates {@link ThreadInfo} data for the sampled threads.
+     *
+     * @param threadBean the thread bean instance to obtain the data from
+     * @return an array of generated thread info instances
+     */
+    ThreadInfo[] dumpThreads(ThreadMXBean threadBean);
+
+    /**
+     * Implementation of {@link ThreadDumper} that generates data for all threads.
+     */
+    ThreadDumper ALL = new All();
+
+    final class All implements ThreadDumper {
+        @Override
+        public ThreadInfo[] dumpThreads(ThreadMXBean threadBean) {
+            return threadBean.dumpAllThreads(false, false);
+        }
+    }
+
+    /**
+     * Implementation of {@link ThreadDumper} that generates data for a specific set of threads.
+     */
+    final class Specific implements ThreadDumper {
+        private final long[] ids;
+
+        public Specific(long[] ids) {
+            this.ids = ids;
+        }
+
+        public Specific(Set<String> names) {
+            Set<String> threadNamesLower = names.stream().map(String::toLowerCase).collect(Collectors.toSet());
+            this.ids = Thread.getAllStackTraces().keySet().stream()
+                    .filter(t -> threadNamesLower.contains(t.getName().toLowerCase()))
+                    .mapToLong(Thread::getId)
+                    .toArray();
+        }
+
+        @Override
+        public ThreadInfo[] dumpThreads(ThreadMXBean threadBean) {
+            return threadBean.getThreadInfo(this.ids, Integer.MAX_VALUE);
+        }
+    }
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/ThreadGrouper.java b/spark-common/src/main/java/me/lucko/spark/sampler/ThreadGrouper.java
new file mode 100644
index 0000000..0707df6
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/ThreadGrouper.java
@@ -0,0 +1,72 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Function for grouping threads together
+ */
+@FunctionalInterface
+public interface ThreadGrouper {
+
+    /**
+     * Gets the group for the given thread.
+     *
+     * @param threadName the name of the thread
+     * @return the group
+     */
+    String getGroup(String threadName);
+
+    /**
+     * Implementation of {@link ThreadGrouper} that just groups by thread name.
+     */
+    ThreadGrouper BY_NAME = new ByName();
+
+    final class ByName implements ThreadGrouper {
+        @Override
+        public String getGroup(String threadName) {
+            return threadName;
+        }
+    }
+
+    /**
+     * Implementation of {@link ThreadGrouper} that attempts to group by the name of the pool
+     * the thread originated from.
+     */
+    ThreadGrouper BY_POOL = new ByPool();
+
+    final class ByPool implements ThreadGrouper {
+        private static final Pattern THREAD_POOL_PATTERN = Pattern.compile("^(.*)[-#] ?\\d+$");
+
+        @Override
+        public String getGroup(String threadName) {
+            Matcher matcher = THREAD_POOL_PATTERN.matcher(threadName);
+            if (!matcher.matches()) {
+                return threadName;
+            }
+
+            return matcher.group(1).trim() + " (Combined)";
+        }
+    }
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/TickCounter.java b/spark-common/src/main/java/me/lucko/spark/sampler/TickCounter.java
new file mode 100644
index 0000000..d6b754b
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/TickCounter.java
@@ -0,0 +1,60 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler;
+
+/**
+ * A hook with the game's "tick loop".
+ */
+public interface TickCounter extends AutoCloseable {
+
+    /**
+     * Starts the counter
+     */
+    void start();
+
+    /**
+     * Stops the counter
+     */
+    @Override
+    void close();
+
+    /**
+     * Gets the current tick number
+     *
+     * @return the current tick
+     */
+    long getCurrentTick();
+
+    /**
+     * Adds a task to be called each time the tick increments
+     *
+     * @param runnable the task
+     */
+    void addTickTask(Runnable runnable);
+
+    /**
+     * Removes a tick task
+     *
+     * @param runnable the task
+     */
+    void removeTickTask(Runnable runnable);
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/DataAggregator.java b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/DataAggregator.java
new file mode 100644
index 0000000..0e38eb4
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/DataAggregator.java
@@ -0,0 +1,54 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.aggregator;
+
+import me.lucko.spark.sampler.node.ThreadNode;
+
+import java.util.Map;
+
+/**
+ * Aggregates sampling data.
+ */
+public interface DataAggregator {
+
+    /**
+     * Called before the sampler begins to insert data
+     */
+    default void start() {
+
+    }
+
+    /**
+     * Forms the output data
+     *
+     * @return the output data
+     */
+    Map<String, ThreadNode> getData();
+
+    /**
+     * Inserts sampling data into this aggregator
+     *
+     * @param threadName the name of the thread
+     * @param stack the call stack
+     */
+    void insertData(String threadName, StackTraceElement[] stack);
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/SimpleDataAggregator.java b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/SimpleDataAggregator.java
new file mode 100644
index 0000000..6f01dd5
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/SimpleDataAggregator.java
@@ -0,0 +1,78 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.aggregator;
+
+import me.lucko.spark.sampler.ThreadGrouper;
+import me.lucko.spark.sampler.node.AbstractNode;
+import me.lucko.spark.sampler.node.ThreadNode;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Basic implementation of {@link DataAggregator}.
+ */
+public class SimpleDataAggregator implements DataAggregator {
+
+    /** A map of root stack nodes for each thread with sampling data */
+    private final Map<String, ThreadNode> threadData = new ConcurrentHashMap<>();
+
+    /** The worker pool used for sampling */
+    private final ExecutorService workerPool;
+
+    /** The instance used to group threads together */
+    private final ThreadGrouper threadGrouper;
+
+    /** The interval to wait between sampling, in milliseconds */
+    private final int interval;
+
+    public SimpleDataAggregator(ExecutorService workerPool, ThreadGrouper threadGrouper, int interval) {
+        this.workerPool = workerPool;
+        this.threadGrouper = threadGrouper;
+        this.interval = interval;
+    }
+
+    @Override
+    public void insertData(String threadName, StackTraceElement[] stack) {
+        try {
+            String group = this.threadGrouper.getGroup(threadName);
+            AbstractNode node = this.threadData.computeIfAbsent(group, ThreadNode::new);
+            node.log(stack, this.interval);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Override
+    public Map<String, ThreadNode> getData() {
+        // wait for all pending data to be inserted
+        this.workerPool.shutdown();
+        try {
+            this.workerPool.awaitTermination(15, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        return this.threadData;
+    }
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/TickedDataAggregator.java b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/TickedDataAggregator.java
new file mode 100644
index 0000000..d78a2a4
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/aggregator/TickedDataAggregator.java
@@ -0,0 +1,179 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.aggregator;
+
+import me.lucko.spark.sampler.ThreadGrouper;
+import me.lucko.spark.sampler.TickCounter;
+import me.lucko.spark.sampler.node.AbstractNode;
+import me.lucko.spark.sampler.node.ThreadNode;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Implementation of {@link DataAggregator} which supports only including sampling data from "ticks"
+ * which exceed a certain threshold in duration.
+ */
+public class TickedDataAggregator implements DataAggregator {
+
+    /** A map of root stack nodes for each thread with sampling data */
+    private final Map<String, ThreadNode> threadData = new ConcurrentHashMap<>();
+
+    /** The worker pool for inserting stack nodes */
+    private final ExecutorService workerPool;
+
+    /** Used to monitor the current "tick" of the server */
+    private final TickCounter tickCounter;
+
+    /** The instance used to group threads together */
+    private final ThreadGrouper threadGrouper;
+
+    /** The interval to wait between sampling, in milliseconds */
+    private final int interval;
+
+    /** Tick durations under this threshold will not be inserted */
+    private final int tickLengthThreshold;
+
+    /** The expected number of samples in each tick */
+    private final int expectedSize;
+
+    private final Object mutex = new Object();
+
+    // state
+    private long currentTick = -1;
+    private TickList currentData = new TickList(0);
+
+    public TickedDataAggregator(ExecutorService workerPool, TickCounter tickCounter, ThreadGrouper threadGrouper, int interval, int tickLengthThreshold) {
+        this.workerPool = workerPool;
+        this.tickCounter = tickCounter;
+        this.threadGrouper = threadGrouper;
+        this.interval = interval;
+        this.tickLengthThreshold = tickLengthThreshold;
+        // 50 millis in a tick, plus 10 so we have a bit of room to go over
+        this.expectedSize = (50 / interval) + 10;
+    }
+
+    @Override
+    public void insertData(String threadName, StackTraceElement[] stack) {
+        synchronized (this.mutex) {
+            long tick = this.tickCounter.getCurrentTick();
+            if (this.currentTick != tick) {
+                pushCurrentTick();
+                this.currentTick = tick;
+                this.currentData = new TickList(this.expectedSize);
+            }
+
+            // form the queued data
+            QueuedThreadInfo queuedData = new QueuedThreadInfo(threadName, stack);
+            // insert it
+            this.currentData.addData(queuedData);
+        }
+    }
+
+    // guarded by 'mutex'
+    private void pushCurrentTick() {
+        TickList currentData = this.currentData;
+
+        // approximate how long the tick lasted
+        int tickLengthMillis = currentData.getList().size() * this.interval;
+
+        // don't push data below the threshold
+        if (tickLengthMillis < this.tickLengthThreshold) {
+            return;
+        }
+
+        this.workerPool.submit(currentData);
+    }
+
+    @Override
+    public void start() {
+        this.tickCounter.start();
+    }
+
+    @Override
+    public Map<String, ThreadNode> getData() {
+        // push the current tick
+        synchronized (this.mutex) {
+            pushCurrentTick();
+        }
+
+        // close the tick counter
+        this.tickCounter.close();
+
+        // wait for all pending data to be inserted
+        this.workerPool.shutdown();
+        try {
+            this.workerPool.awaitTermination(15, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        return this.threadData;
+    }
+
+    // called by TickList
+    void insertData(List<QueuedThreadInfo> dataList) {
+        for (QueuedThreadInfo data : dataList) {
+            try {
+                String group = this.threadGrouper.getGroup(data.threadName);
+                AbstractNode node = this.threadData.computeIfAbsent(group, ThreadNode::new);
+                node.log(data.stack, this.interval);
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private final class TickList implements Runnable {
+        private final List<QueuedThreadInfo> list;
+
+        TickList(int expectedSize) {
+            this.list = new ArrayList<>(expectedSize);
+        }
+
+        @Override
+        public void run() {
+            insertData(this.list);
+        }
+
+        public List<QueuedThreadInfo> getList() {
+            return this.list;
+        }
+
+        public void addData(QueuedThreadInfo data) {
+            this.list.add(data);
+        }
+    }
+
+    private static final class QueuedThreadInfo {
+        private final String threadName;
+        private final StackTraceElement[] stack;
+
+        QueuedThreadInfo(String threadName, StackTraceElement[] stack) {
+            this.threadName = threadName;
+            this.stack = stack;
+        }
+    }
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/node/AbstractNode.java b/spark-common/src/main/java/me/lucko/spark/sampler/node/AbstractNode.java
new file mode 100644
index 0000000..e660140
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/node/AbstractNode.java
@@ -0,0 +1,116 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (C) Albert Pham <http://www.sk89q.com>
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.node;
+
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.LongAdder;
+
+/**
+ * Encapsulates a timed node in the sampling stack.
+ */
+public abstract class AbstractNode {
+
+    private static final int MAX_STACK_DEPTH = 300;
+
+    /**
+     * A map of this nodes children
+     */
+    private final Map<String, StackTraceNode> children = new ConcurrentHashMap<>();
+
+    /**
+     * The accumulated sample time for this node
+     */
+    private final LongAdder totalTime = new LongAdder();
+    
+    public long getTotalTime() {
+        return this.totalTime.longValue();
+    }
+
+    private AbstractNode resolveChild(String className, String methodName) {
+        return this.children.computeIfAbsent(
+                StackTraceNode.generateKey(className, methodName),
+                name -> new StackTraceNode(className, methodName)
+        );
+    }
+
+    public void log(StackTraceElement[] elements, long time) {
+        log(elements, 0, time);
+    }
+    
+    private void log(StackTraceElement[] elements, int skip, long time) {
+        this.totalTime.add(time);
+
+        if (skip >= MAX_STACK_DEPTH) {
+            return;
+        }
+        
+        if (elements.length - skip == 0) {
+            return;
+        }
+        
+        StackTraceElement bottom = elements[elements.length - (skip + 1)];
+        resolveChild(bottom.getClassName(), bottom.getMethodName()).log(elements, skip + 1, time);
+    }
+
+    private Collection<? extends AbstractNode> getChildren() {
+        if (this.children.isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        List<StackTraceNode> list = new ArrayList<>(this.children.values());
+        list.sort(null);
+        return list;
+    }
+
+    public void serializeTo(JsonWriter writer) throws IOException {
+        writer.beginObject();
+
+        // append metadata about this node
+        appendMetadata(writer);
+
+        // include the total time recorded for this node
+        writer.name("t").value(getTotalTime());
+
+        // append child nodes, if any are present
+        Collection<? extends AbstractNode> childNodes = getChildren();
+        if (!childNodes.isEmpty()) {
+            writer.name("c").beginArray();
+            for (AbstractNode child : childNodes) {
+                child.serializeTo(writer);
+            }
+            writer.endArray();
+        }
+
+        writer.endObject();
+    }
+
+    protected abstract void appendMetadata(JsonWriter writer) throws IOException;
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/node/StackTraceNode.java b/spark-common/src/main/java/me/lucko/spark/sampler/node/StackTraceNode.java
new file mode 100644
index 0000000..d161b42
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/node/StackTraceNode.java
@@ -0,0 +1,74 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (C) Albert Pham <http://www.sk89q.com>
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.node;
+
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+
+/**
+ * Represents a stack trace element within the {@link AbstractNode node} structure.
+ */
+public final class StackTraceNode extends AbstractNode implements Comparable<StackTraceNode> {
+
+    /**
+     * Forms a key to represent the given node.
+     *
+     * @param className the name of the class
+     * @param methodName the name of the method
+     * @return the key
+     */
+    static String generateKey(String className, String methodName) {
+        return className + "." + methodName;
+    }
+
+    /** The name of the class */
+    private final String className;
+    /** The name of the method */
+    private final String methodName;
+
+    public StackTraceNode(String className, String methodName) {
+        this.className = className;
+        this.methodName = methodName;
+    }
+
+    @Override
+    protected void appendMetadata(JsonWriter writer) throws IOException {
+        writer.name("cl").value(this.className);
+        writer.name("m").value(this.methodName);
+    }
+
+    private String key() {
+        return generateKey(this.className, this.methodName);
+    }
+
+    @Override
+    public int compareTo(StackTraceNode that) {
+        int i = -Long.compare(this.getTotalTime(), that.getTotalTime());
+        if (i != 0) {
+            return i;
+        }
+
+        return this.key().compareTo(that.key());
+    }
+
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/sampler/node/ThreadNode.java b/spark-common/src/main/java/me/lucko/spark/sampler/node/ThreadNode.java
new file mode 100644
index 0000000..2acce21
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/sampler/node/ThreadNode.java
@@ -0,0 +1,44 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.sampler.node;
+
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+
+/**
+ * The root of a sampling stack for a given thread / thread group.
+ */
+public final class ThreadNode extends AbstractNode {
+
+    /**
+     * The name of this thread
+     */
+    private final String threadName;
+
+    public ThreadNode(String threadName) {
+        this.threadName = threadName;
+    }
+
+    protected void appendMetadata(JsonWriter writer) throws IOException {
+        writer.name("name").value(this.threadName);
+    }
+}