Merge pull request #231 from pstout/pds-dynamic-ids

Add support for Ids that have dynamically commuted tag values.

spectator-api/src/main/java/com/netflix/spectator/api/AbstractDefaultDynamicMeter.java

@@ -0,0 +1,64 @@
+/**
+ * Copyright 2015 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.netflix.spectator.api;
+
+import java.util.function.Function;
+
+/**
+ * Base class for dynamic meters that provides implementations for the core
+ * interface methods.
+ */
+abstract class AbstractDefaultDynamicMeter<T extends Meter> implements Meter {
+  private final DynamicId id;
+  private final Function<Id, T> meterResolver;
+
+  /**
+   * Creates a new dynamic meter.
+   *
+   * @param id the dynamic id for the meter
+   * @param meterResolver the function to map a resolved id to concrete metric
+   */
+  AbstractDefaultDynamicMeter(DynamicId id, Function<Id, T> meterResolver) {
+    this.id = id;
+    this.meterResolver = meterResolver;
+  }
+
+  /**
+   * Resolve the dynamic id to the current metric instance.
+   */
+  protected final T resolveToCurrentMeter() {
+    return meterResolver.apply(id.resolveToId());
+  }
+
+  @Override
+  public final Id id() {
+    return resolveToCurrentMeter().id();
+  }
+
+  @Override
+  public final Iterable<Measurement> measure() {
+    return resolveToCurrentMeter().measure();
+  }
+
+  @Override
+  public final boolean hasExpired() {
+    // Without tracking all of the regular meters that are created from this
+    // dynamic meter we don't have any way of knowing whether the "master"
+    // counter has expired.  Instead of adding the tracking, we choose to
+    // rely on the regular expiration mechanism for the underlying meters.
+    return false;
+  }
+}

spectator-api/src/main/java/com/netflix/spectator/api/AbstractRegistry.java

@@ -74,7 +74,7 @@ public AbstractRegistry(Clock clock) {
   }
 
   @Override public final Id createId(String name) {
-    return new DefaultId(name, TagList.EMPTY);
+    return new DefaultId(name);
   }
 
   @Override public final Id createId(String name, Iterable<Tag> tags) {
@@ -104,7 +104,7 @@ private Meter compute(Meter m, Meter fallback) {
   @Override public final void register(Meter meter) {
     Meter aggr = (meters.size() >= Config.maxNumberOfMeters())
       ? meters.get(meter.id())
-      : meters.computeIfAbsent(meter.id(), id -> new AggrMeter(id));
+      : meters.computeIfAbsent(meter.id(), AggrMeter::new);
     if (aggr != null) {
       addToAggr(aggr, meter);
     }

spectator-api/src/main/java/com/netflix/spectator/api/BasicTag.java

@@ -0,0 +1,75 @@
+/**
+ * Copyright 2015 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.netflix.spectator.api;
+
+import com.netflix.spectator.impl.Preconditions;
+
+/**
+ * Basic container for Tag data.
+ *
+ * Created on 10/1/15.
+ */
+public final class BasicTag implements Tag {
+  private final String key;
+  private final String value;
+  private final int hc;
+
+  /**
+   * Construct a new instance.
+   *
+   * @param key
+   * @param value
+   */
+  public BasicTag(String key, String value) {
+    this.key = Preconditions.checkNotNull(key, "key");
+    this.value = Preconditions.checkNotNull(value, "value");
+    this.hc = 31 * key.hashCode() + value.hashCode();
+  }
+
+  @Override
+  public String key() {
+    return key;
+  }
+
+  @Override
+  public String value() {
+    return value;
+  }
+
+  @Override public boolean equals(Object obj) {
+    if (this == obj) return true;
+    if (obj == null || !(obj instanceof BasicTag)) return false;
+    BasicTag other = (BasicTag) obj;
+    return key.equals(other.key) && value.equals(other.value);
+  }
+
+  /**
+   * This object is immutable and the hash code is precomputed in the constructor. The id object
+   * is typically created to lookup a Meter based on dynamic dimensions so we assume that it is
+   * highly likely that the hash code method will be called and that it could be in a fairly
+   * high volume execution path.
+   *
+   * {@inheritDoc}
+   */
+  @Override public int hashCode() {
+    return hc;
+  }
+
+  @Override
+  public String toString() {
+    return key + '=' + value;
+  }
+}

spectator-api/src/main/java/com/netflix/spectator/api/ConstantTagFactory.java

@@ -0,0 +1,58 @@
+/**
+ * Copyright 2015 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.netflix.spectator.api;
+
+import com.netflix.spectator.impl.Preconditions;
+
+/**
+ * TagFactory implementation that always produces the same tag.  Useful for
+ * providing a default value for a tag.
+ */
+public final class ConstantTagFactory implements TagFactory {
+  private final Tag tag;
+
+  /**
+   * Construct a new instance that will always return a Tag with the specified value.
+   *
+   * @param key
+   *        the non-null key for the tag
+   * @param value
+   *        the non-null value for the tag
+   */
+  public ConstantTagFactory(String key, String value) {
+    this(new TagList(key, value));
+  }
+
+  /**
+   * Construct a new instance that will always return the specified tag.
+   *
+   * @param tag
+   *        the non-null Tag instance to return from createTag
+   */
+  public ConstantTagFactory(Tag tag) {
+    this.tag = Preconditions.checkNotNull(tag, "tag");
+  }
+
+  @Override
+  public String name() {
+    return tag.key();
+  }
+
+  @Override
+  public Tag createTag() {
+    return tag;
+  }
+}

spectator-api/src/main/java/com/netflix/spectator/api/DefaultDynamicCounter.java

@@ -0,0 +1,33 @@
+package com.netflix.spectator.api;
+
+/**
+ * Counter implementation that delegates the value tracking to component counters
+ * based on the current value of the tags associated with the DynamicId when the
+ * increment methods are called.
+ */
+class DefaultDynamicCounter extends AbstractDefaultDynamicMeter<Counter> implements Counter {
+  /**
+   * Constructs a new counter with the specified dynamic id.
+   *
+   * @param id the dynamic (template) id for generating the individual counters
+   * @param registry the registry to use to instantiate the individual counters
+   */
+  DefaultDynamicCounter(DynamicId id, Registry registry) {
+    super(id, registry::counter);
+  }
+
+  @Override
+  public void increment() {
+    resolveToCurrentMeter().increment();
+  }
+
+  @Override
+  public void increment(long amount) {
+    resolveToCurrentMeter().increment(amount);
+  }
+
+  @Override
+  public long count() {
+    return resolveToCurrentMeter().count();
+  }
+}

spectator-api/src/main/java/com/netflix/spectator/api/DefaultDynamicDistributionSummary.java

@@ -0,0 +1,49 @@
+/**
+ * Copyright 2015 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.netflix.spectator.api;
+
+/**
+ * Distribution summary implementation that delegates the value tracking to
+ * component distribution summaries based on the current value of the tags
+ * associated with the DynamicId when the interface methods are called.
+ */
+class DefaultDynamicDistributionSummary extends AbstractDefaultDynamicMeter<DistributionSummary>
+        implements DistributionSummary {
+  /**
+   * Constructs a new distribution summary with the specified dynamic id.
+   *
+   * @param id the dynamic (template) id for generating the individual distribution summaries
+   * @param registry the registry to use to instantiate the individual distribution summaries
+   */
+  DefaultDynamicDistributionSummary(DynamicId id, Registry registry) {
+    super(id, registry::distributionSummary);
+  }
+
+  @Override
+  public void record(long amount) {
+    resolveToCurrentMeter().record(amount);
+  }
+
+  @Override
+  public long count() {
+    return resolveToCurrentMeter().count();
+  }
+
+  @Override
+  public long totalAmount() {
+    return resolveToCurrentMeter().totalAmount();
+  }
+}