Various cleanups in prometheus-metrics-model

CONTRIBUTING.md

@@ -10,3 +10,9 @@ Prometheus uses GitHub to manage reviews of pull requests.
   on our [mailing list](https://groups.google.com/forum/?fromgroups#!forum/prometheus-developers).
   This will avoid unnecessary work and surely give you and us a good deal
   of inspiration.
+
+## Formatting
+
+This repository uses [Google Java Format](https://github.com/google/google-java-format) to format the code.
+
+Run `./mvnw spotless:apply` to format the code (only changed files) before committing.

prometheus-metrics-model/src/main/java/io/prometheus/metrics/model/registry/Collector.java

@@ -1,76 +1,77 @@
 package io.prometheus.metrics.model.registry;
 
 import io.prometheus.metrics.model.snapshots.MetricSnapshot;
-
 import java.util.function.Predicate;
 
-import static io.prometheus.metrics.model.snapshots.PrometheusNaming.prometheusName;
-
 /**
- * To be registered with the Prometheus collector registry.
- * See <i>Overall Structure</i> on
- * <a href="https://prometheus.io/docs/instrumenting/writing_clientlibs/">https://prometheus.io/docs/instrumenting/writing_clientlibs/</a>.
+ * To be registered with the Prometheus collector registry. See <i>Overall Structure</i> on <a
+ * href="https://prometheus.io/docs/instrumenting/writing_clientlibs/">https://prometheus.io/docs/instrumenting/writing_clientlibs/</a>.
  */
 @FunctionalInterface
 public interface Collector {
 
-    /**
-     * Called when the Prometheus server scrapes metrics.
-     */
-    MetricSnapshot collect();
+  /** Called when the Prometheus server scrapes metrics. */
+  MetricSnapshot collect();
 
-    /**
-     * Provides Collector with the details of the request issued by Prometheus to allow multi-target pattern implementation
-     * Override to implement request dependent logic to provide MetricSnapshot
-     */
-	default MetricSnapshot collect(PrometheusScrapeRequest scrapeRequest) {
-		return collect();
-	}
-
-    /**
-     * Like {@link #collect()}, but returns {@code null} if {@code includedNames.test(name)} is {@code false}.
-     * <p>
-     * Override this if there is a more efficient way than first collecting the snapshot and then discarding it.
-     */
-    default MetricSnapshot collect(Predicate<String> includedNames) {
-        MetricSnapshot result = collect();
-        if (includedNames.test(result.getMetadata().getPrometheusName())) {
-            return result;
-        } else {
-            return null;
-        }
-    }
-
-    /**
-     * Like {@link #collect(Predicate)}, but with support for multi-target pattern.
-     * <p>
-     * Override this if there is a more efficient way than first collecting the snapshot and then discarding it.
-     */
-    default MetricSnapshot collect(Predicate<String> includedNames, PrometheusScrapeRequest scrapeRequest) {
-        MetricSnapshot result = collect(scrapeRequest);
-        if (includedNames.test(result.getMetadata().getPrometheusName())) {
-            return result;
-        } else {
-            return null;
-        }
+  /**
+   * Provides Collector with the details of the request issued by Prometheus to allow multi-target
+   * pattern implementation Override to implement request dependent logic to provide MetricSnapshot
+   */
+  default MetricSnapshot collect(PrometheusScrapeRequest scrapeRequest) {
+    return collect();
+  }
+
+  /**
+   * Like {@link #collect()}, but returns {@code null} if {@code includedNames.test(name)} is {@code
+   * false}.
+   *
+   * <p>Override this if there is a more efficient way than first collecting the snapshot and then
+   * discarding it.
+   */
+  default MetricSnapshot collect(Predicate<String> includedNames) {
+    MetricSnapshot result = collect();
+    if (includedNames.test(result.getMetadata().getPrometheusName())) {
+      return result;
+    } else {
+      return null;
     }
-    
+  }
 
-    /**
-     * This is called in two places:
-     * <ol>
-     * <li>During registration to check if a metric with that name already exists.</li>
-     * <li>During scrape to check if this collector can be skipped because a name filter is present and the metric name is excluded.</li>
-     * </ol>
-     * Returning {@code null} means checks are omitted (registration the metric always succeeds),
-     * and the collector is always scraped (the result is dropped after scraping if a name filter is present and
-     * the metric name is excluded).
-     * <p>
-     * If your metric has a name that does not change at runtime it is a good idea to overwrite this and return the name.
-     * <p>
-     * All metrics in {@code prometheus-metrics-core} override this.
-     */
-    default String getPrometheusName() {
-        return null;
+  /**
+   * Like {@link #collect(Predicate)}, but with support for multi-target pattern.
+   *
+   * <p>Override this if there is a more efficient way than first collecting the snapshot and then
+   * discarding it.
+   */
+  default MetricSnapshot collect(
+      Predicate<String> includedNames, PrometheusScrapeRequest scrapeRequest) {
+    MetricSnapshot result = collect(scrapeRequest);
+    if (includedNames.test(result.getMetadata().getPrometheusName())) {
+      return result;
+    } else {
+      return null;
     }
+  }
+
+  /**
+   * This is called in two places:
+   *
+   * <ol>
+   *   <li>During registration to check if a metric with that name already exists.
+   *   <li>During scrape to check if this collector can be skipped because a name filter is present
+   *       and the metric name is excluded.
+   * </ol>
+   *
+   * Returning {@code null} means checks are omitted (registration the metric always succeeds), and
+   * the collector is always scraped (the result is dropped after scraping if a name filter is
+   * present and the metric name is excluded).
+   *
+   * <p>If your metric has a name that does not change at runtime it is a good idea to overwrite
+   * this and return the name.
+   *
+   * <p>All metrics in {@code prometheus-metrics-core} override this.
+   */
+  default String getPrometheusName() {
+    return null;
+  }
 }

prometheus-metrics-model/src/main/java/io/prometheus/metrics/model/registry/PrometheusRegistry.java

@@ -2,128 +2,143 @@
 
 import static io.prometheus.metrics.model.snapshots.PrometheusNaming.prometheusName;
 
+import io.prometheus.metrics.model.snapshots.MetricSnapshot;
+import io.prometheus.metrics.model.snapshots.MetricSnapshots;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Predicate;
 
-import io.prometheus.metrics.model.snapshots.MetricSnapshot;
-import io.prometheus.metrics.model.snapshots.MetricSnapshots;
-
 public class PrometheusRegistry {
 
-	public static final PrometheusRegistry defaultRegistry = new PrometheusRegistry();
-
-	private final Set<String> prometheusNames = ConcurrentHashMap.newKeySet();
-	private final List<Collector> collectors = new CopyOnWriteArrayList<>();
-	private final List<MultiCollector> multiCollectors = new CopyOnWriteArrayList<>();
+  public static final PrometheusRegistry defaultRegistry = new PrometheusRegistry();
 
-	public void register(Collector collector) {
-		String prometheusName = collector.getPrometheusName();
-		if (prometheusName != null) {
-			if (!prometheusNames.add(prometheusName)) {
-				throw new IllegalStateException("Can't register " + prometheusName + " because a metric with that name is already registered.");
-			}
-		}
-		collectors.add(collector);
-	}
+  private final Set<String> prometheusNames = ConcurrentHashMap.newKeySet();
+  private final List<Collector> collectors = new CopyOnWriteArrayList<>();
+  private final List<MultiCollector> multiCollectors = new CopyOnWriteArrayList<>();
 
-	public void register(MultiCollector collector) {
-		for (String prometheusName : collector.getPrometheusNames()) {
-			if (!prometheusNames.add(prometheusName)) {
-				throw new IllegalStateException("Can't register " + prometheusName + " because that name is already registered.");
-			}
-		}
-		multiCollectors.add(collector);
-	}
+  public void register(Collector collector) {
+    String prometheusName = collector.getPrometheusName();
+    if (prometheusName != null) {
+      if (!prometheusNames.add(prometheusName)) {
+        throw new IllegalStateException(
+            "Can't register "
+                + prometheusName
+                + " because a metric with that name is already registered.");
+      }
+    }
+    collectors.add(collector);
+  }
 
-	public void unregister(Collector collector) {
-		collectors.remove(collector);
-		String prometheusName = collector.getPrometheusName();
-		if (prometheusName != null) {
-			prometheusNames.remove(collector.getPrometheusName());
-		}
-	}
+  public void register(MultiCollector collector) {
+    for (String prometheusName : collector.getPrometheusNames()) {
+      if (!prometheusNames.add(prometheusName)) {
+        throw new IllegalStateException(
+            "Can't register " + prometheusName + " because that name is already registered.");
+      }
+    }
+    multiCollectors.add(collector);
+  }
 
-	public void unregister(MultiCollector collector) {
-		multiCollectors.remove(collector);
-		for (String prometheusName : collector.getPrometheusNames()) {
-			prometheusNames.remove(prometheusName(prometheusName));
-		}
-	}
+  public void unregister(Collector collector) {
+    collectors.remove(collector);
+    String prometheusName = collector.getPrometheusName();
+    if (prometheusName != null) {
+      prometheusNames.remove(collector.getPrometheusName());
+    }
+  }
 
-	public MetricSnapshots scrape() {
-		return scrape((PrometheusScrapeRequest) null);
-	}
+  public void unregister(MultiCollector collector) {
+    multiCollectors.remove(collector);
+    for (String prometheusName : collector.getPrometheusNames()) {
+      prometheusNames.remove(prometheusName(prometheusName));
+    }
+  }
 
-	public MetricSnapshots scrape(PrometheusScrapeRequest scrapeRequest) {
-		MetricSnapshots.Builder result = MetricSnapshots.builder();
-		for (Collector collector : collectors) {
-			MetricSnapshot snapshot = scrapeRequest == null ? collector.collect() : collector.collect(scrapeRequest);
-			if (snapshot != null) {
-				if (result.containsMetricName(snapshot.getMetadata().getName())) {
-					throw new IllegalStateException(snapshot.getMetadata().getPrometheusName() + ": duplicate metric name.");
-				}
-				result.metricSnapshot(snapshot);
-			}
-		}
-		for (MultiCollector collector : multiCollectors) {
-			MetricSnapshots snaphots = scrapeRequest == null ? collector.collect() : collector.collect(scrapeRequest);
-			for (MetricSnapshot snapshot : snaphots) {
-				if (result.containsMetricName(snapshot.getMetadata().getName())) {
-					throw new IllegalStateException(snapshot.getMetadata().getPrometheusName() + ": duplicate metric name.");
-				}
-				result.metricSnapshot(snapshot);
-			}
-		}
-		return result.build();
-	}
+  public MetricSnapshots scrape() {
+    return scrape((PrometheusScrapeRequest) null);
+  }
 
-	public MetricSnapshots scrape(Predicate<String> includedNames) {
-		if (includedNames == null) {
-			return scrape();
-		}
-		return scrape(includedNames, null);
-	}
+  public MetricSnapshots scrape(PrometheusScrapeRequest scrapeRequest) {
+    MetricSnapshots.Builder result = MetricSnapshots.builder();
+    for (Collector collector : collectors) {
+      MetricSnapshot snapshot =
+          scrapeRequest == null ? collector.collect() : collector.collect(scrapeRequest);
+      if (snapshot != null) {
+        if (result.containsMetricName(snapshot.getMetadata().getName())) {
+          throw new IllegalStateException(
+              snapshot.getMetadata().getPrometheusName() + ": duplicate metric name.");
+        }
+        result.metricSnapshot(snapshot);
+      }
+    }
+    for (MultiCollector collector : multiCollectors) {
+      MetricSnapshots snapshots =
+          scrapeRequest == null ? collector.collect() : collector.collect(scrapeRequest);
+      for (MetricSnapshot snapshot : snapshots) {
+        if (result.containsMetricName(snapshot.getMetadata().getName())) {
+          throw new IllegalStateException(
+              snapshot.getMetadata().getPrometheusName() + ": duplicate metric name.");
+        }
+        result.metricSnapshot(snapshot);
+      }
+    }
+    return result.build();
+  }
 
-	public MetricSnapshots scrape(Predicate<String> includedNames, PrometheusScrapeRequest scrapeRequest) {
-		if (includedNames == null) {
-			return scrape(scrapeRequest);
-		}
-		MetricSnapshots.Builder result = MetricSnapshots.builder();
-		for (Collector collector : collectors) {
-			String prometheusName = collector.getPrometheusName();
-			// prometheusName == null means the name is unknown, and we have to scrape to learn the name.
-			// prometheusName != null means we can skip the scrape if the name is excluded.
-			if (prometheusName == null || includedNames.test(prometheusName)) {
-				MetricSnapshot snapshot = scrapeRequest == null ? collector.collect(includedNames) : collector.collect(includedNames, scrapeRequest);
-				if (snapshot != null) {
-					result.metricSnapshot(snapshot);
-				}
-			}
-		}
-		for (MultiCollector collector : multiCollectors) {
-			List<String> prometheusNames = collector.getPrometheusNames();
-			// empty prometheusNames means the names are unknown, and we have to scrape to learn the names.
-			// non-empty prometheusNames means we can exclude the collector if all names are excluded by the filter.
-			boolean excluded = !prometheusNames.isEmpty();
-			for (String prometheusName : prometheusNames) {
-				if (includedNames.test(prometheusName)) {
-					excluded = false;
-					break;
-				}
-			}
-			if (!excluded) {
-				MetricSnapshots snapshots = scrapeRequest == null ? collector.collect(includedNames) : collector.collect(includedNames, scrapeRequest);
-				for (MetricSnapshot snapshot : snapshots) {
-					if (snapshot != null) {
-						result.metricSnapshot(snapshot);
-					}
-				}
-			}
-		}
-		return result.build();
-	}
+  public MetricSnapshots scrape(Predicate<String> includedNames) {
+    if (includedNames == null) {
+      return scrape();
+    }
+    return scrape(includedNames, null);
+  }
 
+  public MetricSnapshots scrape(
+      Predicate<String> includedNames, PrometheusScrapeRequest scrapeRequest) {
+    if (includedNames == null) {
+      return scrape(scrapeRequest);
+    }
+    MetricSnapshots.Builder result = MetricSnapshots.builder();
+    for (Collector collector : collectors) {
+      String prometheusName = collector.getPrometheusName();
+      // prometheusName == null means the name is unknown, and we have to scrape to learn the name.
+      // prometheusName != null means we can skip the scrape if the name is excluded.
+      if (prometheusName == null || includedNames.test(prometheusName)) {
+        MetricSnapshot snapshot =
+            scrapeRequest == null
+                ? collector.collect(includedNames)
+                : collector.collect(includedNames, scrapeRequest);
+        if (snapshot != null) {
+          result.metricSnapshot(snapshot);
+        }
+      }
+    }
+    for (MultiCollector collector : multiCollectors) {
+      List<String> prometheusNames = collector.getPrometheusNames();
+      // empty prometheusNames means the names are unknown, and we have to scrape to learn the
+      // names.
+      // non-empty prometheusNames means we can exclude the collector if all names are excluded by
+      // the filter.
+      boolean excluded = !prometheusNames.isEmpty();
+      for (String prometheusName : prometheusNames) {
+        if (includedNames.test(prometheusName)) {
+          excluded = false;
+          break;
+        }
+      }
+      if (!excluded) {
+        MetricSnapshots snapshots =
+            scrapeRequest == null
+                ? collector.collect(includedNames)
+                : collector.collect(includedNames, scrapeRequest);
+        for (MetricSnapshot snapshot : snapshots) {
+          if (snapshot != null) {
+            result.metricSnapshot(snapshot);
+          }
+        }
+      }
+    }
+    return result.build();
+  }
 }