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/*
* Copyright 2016-17, OpenCensus Authors
*
* 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 io.opencensus.implcore.stats;
import io.opencensus.metrics.data.AttachmentValue;
import io.opencensus.stats.Measure;
import io.opencensus.stats.Measure.MeasureDouble;
import io.opencensus.stats.Measure.MeasureLong;
import io.opencensus.stats.Measurement;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
// TODO(songya): consider combining MeasureMapImpl and this class.
/** A map from {@link Measure}'s to measured values. */
final class MeasureMapInternal {
/** Returns a {@link Builder} for the {@link MeasureMapInternal} class. */
static Builder builder() {
return new Builder();
}
/**
* Returns an {@link Iterator} over the measure/value mappings in this {@link MeasureMapInternal}.
* The {@code Iterator} does not support {@link Iterator#remove()}.
*/
Iterator iterator() {
return new MeasureMapInternalIterator();
}
// Returns the contextual information associated with an example value.
Map getAttachments() {
return attachments;
}
private final ArrayList measurements;
private final Map attachments;
private MeasureMapInternal(
ArrayList measurements, Map attachments) {
this.measurements = measurements;
this.attachments =
Collections.unmodifiableMap(new HashMap(attachments));
}
/** Builder for the {@link MeasureMapInternal} class. */
static class Builder {
/**
* Associates the {@link MeasureDouble} with the given value. Subsequent updates to the same
* {@link MeasureDouble} will overwrite the previous value.
*
* @param measure the {@link MeasureDouble}
* @param value the value to be associated with {@code measure}
* @return this
*/
Builder put(MeasureDouble measure, double value) {
measurements.add(Measurement.MeasurementDouble.create(measure, value));
return this;
}
/**
* Associates the {@link MeasureLong} with the given value. Subsequent updates to the same
* {@link MeasureLong} will overwrite the previous value.
*
* @param measure the {@link MeasureLong}
* @param value the value to be associated with {@code measure}
* @return this
*/
Builder put(MeasureLong measure, long value) {
measurements.add(Measurement.MeasurementLong.create(measure, value));
return this;
}
Builder putAttachment(String key, AttachmentValue value) {
this.attachments.put(key, value);
return this;
}
/** Constructs a {@link MeasureMapInternal} from the current measurements. */
MeasureMapInternal build() {
// Note: this makes adding measurements quadratic but is fastest for the sizes of
// MeasureMapInternals that we should see. We may want to go to a strategy of sort/eliminate
// for larger MeasureMapInternals.
for (int i = measurements.size() - 1; i >= 0; i--) {
for (int j = i - 1; j >= 0; j--) {
if (measurements.get(i).getMeasure() == measurements.get(j).getMeasure()) {
measurements.remove(j);
j--;
}
}
}
return new MeasureMapInternal(measurements, attachments);
}
private final ArrayList measurements = new ArrayList();
private final Map attachments = new HashMap();
private Builder() {}
}
// Provides an unmodifiable Iterator over this instance's measurements.
private final class MeasureMapInternalIterator implements Iterator {
@Override
public boolean hasNext() {
return position < length;
}
@Override
public Measurement next() {
if (position >= measurements.size()) {
throw new NoSuchElementException();
}
return measurements.get(position++);
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
private final int length = measurements.size();
private int position = 0;
}
}