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      1 /*
      2  * Copyright 2017, OpenCensus Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package io.opencensus.stats;
     18 
     19 import io.opencensus.internal.Utils;
     20 import io.opencensus.stats.Measure.MeasureDouble;
     21 import io.opencensus.stats.Measure.MeasureLong;
     22 import io.opencensus.tags.TagContext;
     23 import javax.annotation.concurrent.NotThreadSafe;
     24 
     25 /**
     26  * A map from {@link Measure}s to measured values to be recorded at the same time.
     27  *
     28  * @since 0.8
     29  */
     30 @NotThreadSafe
     31 public abstract class MeasureMap {
     32 
     33   /**
     34    * Associates the {@link MeasureDouble} with the given value. Subsequent updates to the same
     35    * {@link MeasureDouble} will overwrite the previous value.
     36    *
     37    * @param measure the {@link MeasureDouble}
     38    * @param value the value to be associated with {@code measure}
     39    * @return this
     40    * @since 0.8
     41    */
     42   public abstract MeasureMap put(MeasureDouble measure, double value);
     43 
     44   /**
     45    * Associates the {@link MeasureLong} with the given value. Subsequent updates to the same {@link
     46    * MeasureLong} will overwrite the previous value.
     47    *
     48    * @param measure the {@link MeasureLong}
     49    * @param value the value to be associated with {@code measure}
     50    * @return this
     51    * @since 0.8
     52    */
     53   public abstract MeasureMap put(MeasureLong measure, long value);
     54 
     55   /**
     56    * Associate the contextual information of an {@code Exemplar} to this {@link MeasureMap}.
     57    * Contextual information is represented as {@code String} key-value pairs.
     58    *
     59    * <p>If this method is called multiple times with the same key, only the last value will be kept.
     60    *
     61    * @param key the key of contextual information of an {@code Exemplar}.
     62    * @param value the string representation of contextual information of an {@code Exemplar}.
     63    * @return this
     64    * @since 0.16
     65    */
     66   // TODO(songya): make this method abstract in the 0.17 release.
     67   public MeasureMap putAttachment(String key, String value) {
     68     // Provides a default no-op implementation to avoid breaking other existing sub-classes.
     69     Utils.checkNotNull(key, "key");
     70     Utils.checkNotNull(value, "value");
     71     return this;
     72   }
     73 
     74   /**
     75    * Records all of the measures at the same time, with the current {@link TagContext}.
     76    *
     77    * <p>This method records all of the stats in the {@code MeasureMap} every time it is called.
     78    *
     79    * @since 0.8
     80    */
     81   public abstract void record();
     82 
     83   /**
     84    * Records all of the measures at the same time, with an explicit {@link TagContext}.
     85    *
     86    * <p>This method records all of the stats in the {@code MeasureMap} every time it is called.
     87    *
     88    * @param tags the tags associated with the measurements.
     89    * @since 0.8
     90    */
     91   public abstract void record(TagContext tags);
     92 }
     93