format

Signed-off-by: Gregor Zeitlinger <gregor.zeitlinger@grafana.com>

Author: zeitlinger

prometheus-metrics-core/src/main/java/io/prometheus/metrics/core/metrics/Buffer.java

@@ -1,7 +1,6 @@
 package io.prometheus.metrics.core.metrics;
 
 import io.prometheus.metrics.model.snapshots.DataPointSnapshot;
-
 import java.util.Arrays;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.Condition;
@@ -12,102 +11,104 @@
 
 /**
  * Metrics support concurrent write and scrape operations.
- * <p>
- * This is implemented by switching to a Buffer when the scrape starts,
- * and applying the values from the buffer after the scrape ends.
+ *
+ * <p>This is implemented by switching to a Buffer when the scrape starts, and applying the values
+ * from the buffer after the scrape ends.
  */
 class Buffer {
 
-    private static final long bufferActiveBit = 1L << 63;
-    private final AtomicLong observationCount = new AtomicLong(0);
-    private double[] observationBuffer = new double[0];
-    private int bufferPos = 0;
-    private boolean reset = false;
-
-    ReentrantLock appendLock = new ReentrantLock();
-    ReentrantLock runLock = new ReentrantLock();
-    Condition bufferFilled = appendLock.newCondition();
-
-    boolean append(double value) {
-        long count = observationCount.incrementAndGet();
-        if ((count & bufferActiveBit) == 0) {
-            return false; // sign bit not set -> buffer not active.
+  private static final long bufferActiveBit = 1L << 63;
+  private final AtomicLong observationCount = new AtomicLong(0);
+  private double[] observationBuffer = new double[0];
+  private int bufferPos = 0;
+  private boolean reset = false;
+
+  ReentrantLock appendLock = new ReentrantLock();
+  ReentrantLock runLock = new ReentrantLock();
+  Condition bufferFilled = appendLock.newCondition();
+
+  boolean append(double value) {
+    long count = observationCount.incrementAndGet();
+    if ((count & bufferActiveBit) == 0) {
+      return false; // sign bit not set -> buffer not active.
+    } else {
+      doAppend(value);
+      return true;
+    }
+  }
+
+  private void doAppend(double amount) {
+    try {
+      appendLock.lock();
+      if (bufferPos >= observationBuffer.length) {
+        observationBuffer = Arrays.copyOf(observationBuffer, observationBuffer.length + 128);
+      }
+      observationBuffer[bufferPos] = amount;
+      bufferPos++;
+
+      bufferFilled.signalAll();
+    } finally {
+      appendLock.unlock();
+    }
+  }
+
+  /** Must be called by the runnable in the run() method. */
+  void reset() {
+    reset = true;
+  }
+
+  <T extends DataPointSnapshot> T run(
+      Function<Long, Boolean> complete,
+      Supplier<T> createResult,
+      Consumer<Double> observeFunction) {
+    double[] buffer;
+    int bufferSize;
+    T result;
+    try {
+      runLock.lock();
+
+      // Signal that the buffer is active.
+      Long expectedCount = observationCount.getAndAdd(bufferActiveBit);
+      try {
+        appendLock.lock();
+
+        while (!complete.apply(expectedCount)) {
+          // Wait until all in-flight threads have added their observations to the buffer.
+          bufferFilled.await();
+        }
+        result = createResult.get();
+
+        // Signal that the buffer is inactive.
+        int expectedBufferSize;
+        if (reset) {
+          expectedBufferSize =
+              (int) ((observationCount.getAndSet(0) & ~bufferActiveBit) - expectedCount);
+          reset = false;
         } else {
-            doAppend(value);
-            return true;
+          expectedBufferSize = (int) (observationCount.addAndGet(bufferActiveBit) - expectedCount);
         }
-    }
 
-    private void doAppend(double amount) {
-        try {
-            appendLock.lock();
-            if (bufferPos >= observationBuffer.length) {
-                observationBuffer = Arrays.copyOf(observationBuffer, observationBuffer.length + 128);
-            }
-            observationBuffer[bufferPos] = amount;
-            bufferPos++;
-
-            bufferFilled.signalAll();
-        } finally {
-            appendLock.unlock();
+        while (bufferPos < expectedBufferSize) {
+          // Wait until all in-flight threads have added their observations to the buffer.
+          bufferFilled.await();
         }
+      } finally {
+        appendLock.unlock();
+      }
+
+      buffer = observationBuffer;
+      bufferSize = bufferPos;
+      observationBuffer = new double[0];
+      bufferPos = 0;
+    } catch (InterruptedException e) {
+      throw new RuntimeException(e);
+    } finally {
+      runLock.unlock();
     }
 
-    /**
-     * Must be called by the runnable in the run() method.
-     */
-    void reset() {
-        reset = true;
-    }
-
-    <T extends DataPointSnapshot> T run(Function<Long, Boolean> complete, Supplier<T> createResult, Consumer<Double> observeFunction) {
-        double[] buffer;
-        int bufferSize;
-        T result;
-        try {
-            runLock.lock();
-
-            // Signal that the buffer is active.
-            Long expectedCount = observationCount.getAndAdd(bufferActiveBit);
-            try {
-                appendLock.lock();
-
-                while (!complete.apply(expectedCount)) {
-                    // Wait until all in-flight threads have added their observations to the buffer.
-                    bufferFilled.await();
-                }
-                result = createResult.get();
-
-                // Signal that the buffer is inactive.
-                int expectedBufferSize;
-                if (reset) {
-                    expectedBufferSize = (int) ((observationCount.getAndSet(0) & ~bufferActiveBit) - expectedCount);
-                    reset = false;
-                } else {
-                    expectedBufferSize = (int) (observationCount.addAndGet(bufferActiveBit) - expectedCount);
-                }
-
-                while (bufferPos < expectedBufferSize) {
-                    // Wait until all in-flight threads have added their observations to the buffer.
-                    bufferFilled.await();
-                }
-            } finally {
-                appendLock.unlock();
-            }
-
-            buffer = observationBuffer;
-            bufferSize = bufferPos;
-            observationBuffer = new double[0];
-            bufferPos = 0;
-        } catch (InterruptedException e) {
-            throw new RuntimeException(e);
-        } finally {
-            runLock.unlock();
-        }
-
-        for (int i = 0; i < bufferSize; i++) {
-            observeFunction.accept(buffer[i]);
-        }
-        return result;
+    for (int i = 0; i < bufferSize; i++) {
+      observeFunction.accept(buffer[i]);
     }
+    return result;
+  }
 }