/// <summary>Creates a new metric definition from the provided information, or returns an existing matching definition if found.</summary>
/// <remarks>If the metric definition doesn't exist, it will be created.
/// If the metric definition does exist, but is not a Custom Sampled Metric (or a derived class) an exception will be thrown.
/// Definitions are looked up and added to the provided definitions dictionary.</remarks>
/// <param name="definitions">The definitions dictionary this definition is a part of</param>
/// <param name="metricTypeName">The unique metric type</param>
/// <param name="categoryName">The name of the category with which this definition is associated.</param>
/// <param name="counterName">The name of the definition within the category.</param>
public static EventMetricDefinition AddOrGet(MetricDefinitionCollection definitions, string metricTypeName, string categoryName, string counterName)
{
//we must have a definitions collection, or we have a problem
if (definitions == null)
{
throw new ArgumentNullException(nameof(definitions));
}
//we need to find the definition, adding it if necessary
string definitionKey = GetKey(metricTypeName, categoryName, counterName);
IMetricDefinition definition;
//We need to grab a lock so our try get & the create are done as one lock.
lock (definitions.Lock)
{
if (definitions.TryGetValue(definitionKey, out definition))
{
//if the metric definition exists, but is of the wrong type we have a problem.
if ((definition is CustomSampledMetricDefinition) == false)
{
throw new ArgumentException("A metric already exists with the provided type, category, and counter name but it is not compatible with being an event metric. Please use a different counter name.", nameof(counterName));
}
}
else
{
//we didn't find one, make a new one
definition = new EventMetricDefinition(definitions, metricTypeName, categoryName, counterName);
definitions.Add(definition); // Add it to the collection, no longer done in the constructor.
// ToDo: Reconsider this implementation; putting incomplete event metric definitions in the collection is not ideal.
}
}
return((EventMetricDefinition)definition);
}
/// <summary>
/// Create a new sampled metric object from the provided raw data packet.
/// </summary>
/// <remarks>The metric definition <b>will</b> be automatically added to the provided collection.</remarks>
/// <param name="definitions">The definitions dictionary this definition is a part of.</param>
/// <param name="packet">The packet to create a definition from.</param>
internal SampledMetricDefinition(MetricDefinitionCollection definitions, SampledMetricDefinitionPacket packet)
: base(definitions, packet)
{
// After the base constructor, auto-add ourself to the definition collection
SetReadOnly(); // Make sure we're read-only before we're added to the collection.
definitions.Add(this); // ToDo: Determine whether to keep or discard this behavior for sampled metrics.
}
/// <summary>Creates a new metric instance or returns an existing one from the provided definition information, or returns any existing instance if found.</summary>
/// <remarks>If the metric definition doesn't exist, it will be created. If the metric doesn't exist, it will be created.
/// If the metric definition does exist, but is not an Event Metric (or a derived class) an exception will be thrown.</remarks>
/// <param name="definitions">The definitions dictionary this definition is a part of</param>
/// <param name="metricTypeName">The unique metric type</param>
/// <param name="categoryName">The name of the category with which this definition is associated.</param>
/// <param name="counterName">The name of the definition within the category.</param>
/// <param name="instanceName">The unique name of this instance within the metric's collection.</param>
/// <returns>The event metric object for the specified event metric instance.</returns>
public static EventMetric AddOrGet(MetricDefinitionCollection definitions, string metricTypeName, string categoryName, string counterName, string instanceName)
{
//we must have a definitions collection, or we have a problem
if (definitions == null)
{
throw new ArgumentNullException(nameof(definitions));
}
//we need to find the definition, adding it if necessary
string definitionKey = MetricDefinition.GetKey(metricTypeName, categoryName, counterName);
IMetricDefinition definition;
if (definitions.TryGetValue(definitionKey, out definition))
{
//if the metric definition exists, but is of the wrong type we have a problem.
if ((definition is EventMetricDefinition) == false)
{
throw new ArgumentException("A metric already exists with the provided type, category, and counter name but it is not compatible with being an event metric. Please use a different counter name.", nameof(counterName));
}
}
else
{
//we didn't find one, make a new one
definition = new EventMetricDefinition(definitions, metricTypeName, categoryName, counterName);
definitions.Add(definition); // Add it to the collection, no longer done in the constructor.
// ToDo: Reconsider this implementation; putting incomplete event metric definitions in the collection is not ideal,
// and creating a metric from an empty event metric definition is fairly pointless.
}
//now we have our definition, proceed to create a new metric if it doesn't exist
string metricKey = MetricDefinition.GetKey(metricTypeName, categoryName, counterName, instanceName);
IMetric metric;
//see if we can get the metric already. If not, we'll create it
lock (((MetricCollection)definition.Metrics).Lock) //make sure the get & add are atomic
{
if (definition.Metrics.TryGetValue(metricKey, out metric) == false)
{
metric = new EventMetric((EventMetricDefinition)definition, instanceName);
}
}
return((EventMetric)metric);
}
/// <summary>
/// Register this instance as a completed definition and return the valid usable definition for this event metric.
/// </summary>
/// <remarks>This call is necessary to complete a new event metric definition (created by calls to AddValue) before
/// it can be used, and it signifies that all desired value columns have been added to the definition. Only the
/// first registration of a metric definition with a given Key (metrics system, category name, and counter name)
/// will be effective and return the same definition object; subsequent calls (perhaps by another thread) will
/// instead return the existing definition already registered. If a definition already registered with that Key
/// can not be an event metric (e.g. a sampled metric is defined with that Key) or if this instance defined value
/// columns not present as compatible value columns in the existing registered definition with that Key, then an
/// ArgumentException will be thrown to signal your programming mistake.</remarks>
/// <returns>The actual usable definition with the same metrics system, category name, and counter name as this instance.</returns>
public EventMetricDefinition Register()
{
EventMetricDefinition officialDefinition;
MetricDefinitionCollection definitionCollection = (MetricDefinitionCollection)Definitions;
// We need to lock the collection while we check for an existing definition and maybe add this one to it.
lock (definitionCollection.Lock)
{
IMetricDefinition rawDefinition;
if (definitionCollection.TryGetValue(MetricTypeName, CategoryName, CounterName, out rawDefinition) == false)
{
// There isn't already one by that Key. Great! Register ourselves.
SetReadOnly(); // Mark this definition as completed.
officialDefinition = this;
definitionCollection.Add(this);
}
else
{
// Oooh, we found one already registered. We'll want to do some checking on this, but outside the lock.
officialDefinition = rawDefinition as EventMetricDefinition;
}
} // End of collection lock
if (officialDefinition == null)
{
throw new ArgumentException(
string.Format(
"There is already a metric definition for the same metrics system ({0}), category name ({1}), and counter name ({2}), but it is not an event metric.",
MetricTypeName, CategoryName, CounterName));
}
else if (this != officialDefinition)
{
// There was one other than us, make sure it's compatible with us.
IEventMetricValueDefinitionCollection officialValues = officialDefinition.Values;
foreach (EventMetricValueDefinition ourValue in Values)
{
IEventMetricValueDefinition officialValue;
if (officialValues.TryGetValue(ourValue.Name, out officialValue) == false)
{
// It doesn't have one of our value columns!
throw new ArgumentException(
string.Format(
"There is already an event metric definition for the same metrics system ({0}), category name ({1}), and counter name ({2}), but it is not compatible; it does not define value column \"{3}\".",
MetricTypeName, CategoryName, CounterName, ourValue.Name));
}
else if (ourValue.SerializedType != ((EventMetricValueDefinition)officialValue).SerializedType)
{
throw new ArgumentException(
string.Format(
"There is already an event metric definition for the same metrics system ({0}), category name ({1}), and counter name ({2}), but it is not compatible; " +
"it defines value column \"{3}\" with type {4} rather than type {5}.",
MetricTypeName, CategoryName, CounterName, ourValue.Name, officialValue.Type.Name, ourValue.Type.Name));
}
}
// We got through all the values defined in this instance? Then we're okay to return the official one.
}
// Otherwise, it's just us, so we're all good.
return(officialDefinition);
}