// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
//
// DataflowBlockOptions.cs
//
//
// DataflowBlockOptions types for configuring dataflow blocks
//
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
using System;
using System.Diagnostics;
using System.Threading.Tasks;
namespace System.Threading.Tasks.Dataflow
{
/// <summary>
/// Provides options used to configure the processing performed by dataflow blocks.
/// </summary>
/// <remarks>
/// <see cref="DataflowBlockOptions"/> is mutable and can be configured through its properties.
/// When specific configuration options are not set, the following defaults are used:
/// <list type="table">
/// <listheader>
/// <term>Options</term>
/// <description>Default</description>
/// </listheader>
/// <item>
/// <term>TaskScheduler</term>
/// <description><see cref="System.Threading.Tasks.TaskScheduler.Default"/></description>
/// </item>
/// <item>
/// <term>MaxMessagesPerTask</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>CancellationToken</term>
/// <description><see cref="System.Threading.CancellationToken.None"/></description>
/// </item>
/// <item>
/// <term>BoundedCapacity</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>NameFormat</term>
/// <description>"{0} Id={1}"</description>
/// </item>
/// </list>
/// Dataflow blocks capture the state of the options at their construction. Subsequent changes
/// to the provided <see cref="DataflowBlockOptions"/> instance should not affect the behavior
/// of a dataflow block.
/// </remarks>
[DebuggerDisplay("TaskScheduler = {TaskScheduler}, MaxMessagesPerTask = {MaxMessagesPerTask}, BoundedCapacity = {BoundedCapacity}")]
public class DataflowBlockOptions
{
/// <summary>
/// A constant used to specify an unlimited quantity for <see cref="DataflowBlockOptions"/> members
/// that provide an upper bound. This field is constant.
/// </summary>
public const Int32 Unbounded = -1;
/// <summary>The scheduler to use for scheduling tasks to process messages.</summary>
private TaskScheduler _taskScheduler = TaskScheduler.Default;
/// <summary>The cancellation token to monitor for cancellation requests.</summary>
private CancellationToken _cancellationToken = CancellationToken.None;
/// <summary>The maximum number of messages that may be processed per task.</summary>
private Int32 _maxMessagesPerTask = Unbounded;
/// <summary>The maximum number of messages that may be buffered by the block.</summary>
private Int32 _boundedCapacity = Unbounded;
/// <summary>The name format to use for creating a name for a block.</summary>
private string _nameFormat = "{0} Id={1}"; // see NameFormat property for a description of format items
/// <summary>A default instance of <see cref="DataflowBlockOptions"/>.</summary>
/// <remarks>
/// Do not change the values of this instance. It is shared by all of our blocks when no options are provided by the user.
/// </remarks>
internal static readonly DataflowBlockOptions Default = new DataflowBlockOptions();
/// <summary>Returns this <see cref="DataflowBlockOptions"/> instance if it's the default instance or else a cloned instance.</summary>
/// <returns>An instance of the options that may be cached by the block.</returns>
internal DataflowBlockOptions DefaultOrClone()
{
return (this == Default) ?
this :
new DataflowBlockOptions
{
TaskScheduler = this.TaskScheduler,
CancellationToken = this.CancellationToken,
MaxMessagesPerTask = this.MaxMessagesPerTask,
BoundedCapacity = this.BoundedCapacity,
NameFormat = this.NameFormat
};
}
/// <summary>Initializes the <see cref="DataflowBlockOptions"/>.</summary>
public DataflowBlockOptions() { }
/// <summary>Gets or sets the <see cref="System.Threading.Tasks.TaskScheduler"/> to use for scheduling tasks.</summary>
public TaskScheduler TaskScheduler
{
get { return _taskScheduler; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value == null) throw new ArgumentNullException("value");
_taskScheduler = value;
}
}
/// <summary>Gets or sets the <see cref="System.Threading.CancellationToken"/> to monitor for cancellation requests.</summary>
public CancellationToken CancellationToken
{
get { return _cancellationToken; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
_cancellationToken = value;
}
}
/// <summary>Gets or sets the maximum number of messages that may be processed per task.</summary>
public Int32 MaxMessagesPerTask
{
get { return _maxMessagesPerTask; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value < 1 && value != Unbounded) throw new ArgumentOutOfRangeException("value");
_maxMessagesPerTask = value;
}
}
/// <summary>Gets a MaxMessagesPerTask value that may be used for comparison purposes.</summary>
/// <returns>The maximum value, usable for comparison purposes.</returns>
/// <remarks>Unlike MaxMessagesPerTask, this property will always return a positive value.</remarks>
internal Int32 ActualMaxMessagesPerTask
{
get { return (_maxMessagesPerTask == Unbounded) ? Int32.MaxValue : _maxMessagesPerTask; }
}
/// <summary>Gets or sets the maximum number of messages that may be buffered by the block.</summary>
public Int32 BoundedCapacity
{
get { return _boundedCapacity; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value < 1 && value != Unbounded) throw new ArgumentOutOfRangeException("value");
_boundedCapacity = value;
}
}
/// <summary>
/// Gets or sets the format string to use when a block is queried for its name.
/// </summary>
/// <remarks>
/// The name format may contain up to two format items. {0} will be substituted
/// with the block's name. {1} will be substituted with the block's Id, as is
/// returned from the block's Completion.Id property.
/// </remarks>
public string NameFormat
{
get { return _nameFormat; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value == null) throw new ArgumentNullException("value");
_nameFormat = value;
}
}
}
/// <summary>
/// Provides options used to configure the processing performed by dataflow blocks that
/// process each message through the invocation of a user-provided delegate, blocks such
/// as <see cref="ActionBlock{T}"/> and <see cref="TransformBlock{TInput,TOutput}"/>.
/// </summary>
/// <remarks>
/// <see cref="ExecutionDataflowBlockOptions"/> is mutable and can be configured through its properties.
/// When specific configuration options are not set, the following defaults are used:
/// <list type="table">
/// <listheader>
/// <term>Options</term>
/// <description>Default</description>
/// </listheader>
/// <item>
/// <term>TaskScheduler</term>
/// <description><see cref="System.Threading.Tasks.TaskScheduler.Default"/></description>
/// </item>
/// <item>
/// <term>CancellationToken</term>
/// <description><see cref="System.Threading.CancellationToken.None"/></description>
/// </item>
/// <item>
/// <term>MaxMessagesPerTask</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>BoundedCapacity</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>NameFormat</term>
/// <description>"{0} Id={1}"</description>
/// </item>
/// <item>
/// <term>MaxDegreeOfParallelism</term>
/// <description>1</description>
/// </item>
/// <item>
/// <term>SingleProducerConstrained</term>
/// <description>false</description>
/// </item>
/// </list>
/// Dataflow block captures the state of the options at their construction. Subsequent changes
/// to the provided <see cref="ExecutionDataflowBlockOptions"/> instance should not affect the behavior
/// of a dataflow block.
/// </remarks>
[DebuggerDisplay("TaskScheduler = {TaskScheduler}, MaxMessagesPerTask = {MaxMessagesPerTask}, BoundedCapacity = {BoundedCapacity}, MaxDegreeOfParallelism = {MaxDegreeOfParallelism}")]
public class ExecutionDataflowBlockOptions : DataflowBlockOptions
{
/// <summary>A default instance of <see cref="DataflowBlockOptions"/>.</summary>
/// <remarks>
/// Do not change the values of this instance. It is shared by all of our blocks when no options are provided by the user.
/// </remarks>
internal new static readonly ExecutionDataflowBlockOptions Default = new ExecutionDataflowBlockOptions();
/// <summary>Returns this <see cref="ExecutionDataflowBlockOptions"/> instance if it's the default instance or else a cloned instance.</summary>
/// <returns>An instance of the options that may be cached by the block.</returns>
internal new ExecutionDataflowBlockOptions DefaultOrClone()
{
return (this == Default) ?
this :
new ExecutionDataflowBlockOptions
{
TaskScheduler = this.TaskScheduler,
CancellationToken = this.CancellationToken,
MaxMessagesPerTask = this.MaxMessagesPerTask,
BoundedCapacity = this.BoundedCapacity,
NameFormat = this.NameFormat,
MaxDegreeOfParallelism = this.MaxDegreeOfParallelism,
SingleProducerConstrained = this.SingleProducerConstrained
};
}
/// <summary>The maximum number of tasks that may be used concurrently to process messages.</summary>
private Int32 _maxDegreeOfParallelism = 1;
/// <summary>Whether the code using this block will only ever have a single producer accessing the block at any given time.</summary>
private Boolean _singleProducerConstrained = false;
/// <summary>Initializes the <see cref="ExecutionDataflowBlockOptions"/>.</summary>
public ExecutionDataflowBlockOptions() { }
/// <summary>Gets the maximum number of messages that may be processed by the block concurrently.</summary>
public Int32 MaxDegreeOfParallelism
{
get { return _maxDegreeOfParallelism; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value < 1 && value != Unbounded) throw new ArgumentOutOfRangeException("value");
_maxDegreeOfParallelism = value;
}
}
/// <summary>
/// Gets whether code using the dataflow block is constrained to one producer at a time.
/// </summary>
/// <remarks>
/// This property defaults to false, such that the block may be used by multiple
/// producers concurrently. This property should only be set to true if the code
/// using the block can guarantee that it will only ever be used by one producer
/// (e.g. a source linked to the block) at a time, meaning that methods like Post,
/// Complete, Fault, and OfferMessage will never be called concurrently. Some blocks
/// may choose to capitalize on the knowledge that there will only be one producer at a time
/// in order to provide better performance.
/// </remarks>
public Boolean SingleProducerConstrained
{
get { return _singleProducerConstrained; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
_singleProducerConstrained = value;
}
}
/// <summary>Gets a MaxDegreeOfParallelism value that may be used for comparison purposes.</summary>
/// <returns>The maximum value, usable for comparison purposes.</returns>
/// <remarks>Unlike MaxDegreeOfParallelism, this property will always return a positive value.</remarks>
internal Int32 ActualMaxDegreeOfParallelism
{
get { return (_maxDegreeOfParallelism == Unbounded) ? Int32.MaxValue : _maxDegreeOfParallelism; }
}
/// <summary>Gets whether these dataflow block options allow for parallel execution.</summary>
internal Boolean SupportsParallelExecution { get { return _maxDegreeOfParallelism == Unbounded || _maxDegreeOfParallelism > 1; } }
}
/// <summary>
/// Provides options used to configure the processing performed by dataflow blocks that
/// group together multiple messages, blocks such as <see cref="JoinBlock{T1,T2}"/> and
/// <see cref="BatchBlock{T}"/>.
/// </summary>
/// <remarks>
/// <see cref="GroupingDataflowBlockOptions"/> is mutable and can be configured through its properties.
/// When specific configuration options are not set, the following defaults are used:
/// <list type="table">
/// <listheader>
/// <term>Options</term>
/// <description>Default</description>
/// </listheader>
/// <item>
/// <term>TaskScheduler</term>
/// <description><see cref="System.Threading.Tasks.TaskScheduler.Default"/></description>
/// </item>
/// <item>
/// <term>CancellationToken</term>
/// <description><see cref="System.Threading.CancellationToken.None"/></description>
/// </item>
/// <item>
/// <term>MaxMessagesPerTask</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>BoundedCapacity</term>
/// <description>DataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>NameFormat</term>
/// <description>"{0} Id={1}"</description>
/// </item>
/// <item>
/// <term>MaxNumberOfGroups</term>
/// <description>GroupingDataflowBlockOptions.Unbounded (-1)</description>
/// </item>
/// <item>
/// <term>Greedy</term>
/// <description>true</description>
/// </item>
/// </list>
/// Dataflow block capture the state of the options at their construction. Subsequent changes
/// to the provided <see cref="GroupingDataflowBlockOptions"/> instance should not affect the behavior
/// of a dataflow block.
/// </remarks>
[DebuggerDisplay("TaskScheduler = {TaskScheduler}, MaxMessagesPerTask = {MaxMessagesPerTask}, BoundedCapacity = {BoundedCapacity}, Greedy = {Greedy}, MaxNumberOfGroups = {MaxNumberOfGroups}")]
public class GroupingDataflowBlockOptions : DataflowBlockOptions
{
/// <summary>A default instance of <see cref="DataflowBlockOptions"/>.</summary>
/// <remarks>
/// Do not change the values of this instance. It is shared by all of our blocks when no options are provided by the user.
/// </remarks>
internal new static readonly GroupingDataflowBlockOptions Default = new GroupingDataflowBlockOptions();
/// <summary>Returns this <see cref="GroupingDataflowBlockOptions"/> instance if it's the default instance or else a cloned instance.</summary>
/// <returns>An instance of the options that may be cached by the block.</returns>
internal new GroupingDataflowBlockOptions DefaultOrClone()
{
return (this == Default) ?
this :
new GroupingDataflowBlockOptions
{
TaskScheduler = this.TaskScheduler,
CancellationToken = this.CancellationToken,
MaxMessagesPerTask = this.MaxMessagesPerTask,
BoundedCapacity = this.BoundedCapacity,
NameFormat = this.NameFormat,
Greedy = this.Greedy,
MaxNumberOfGroups = this.MaxNumberOfGroups
};
}
/// <summary>Whether the block should greedily consume offered messages.</summary>
private Boolean _greedy = true;
/// <summary>The maximum number of groups that should be generated by the block.</summary>
private Int64 _maxNumberOfGroups = Unbounded;
/// <summary>Initializes the <see cref="GroupingDataflowBlockOptions"/>.</summary>
public GroupingDataflowBlockOptions() { }
/// <summary>Gets or sets the Boolean value to use to determine whether to greedily consume offered messages.</summary>
public Boolean Greedy
{
get { return _greedy; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
_greedy = value;
}
}
/// <summary>Gets or sets the maximum number of groups that should be generated by the block.</summary>
public Int64 MaxNumberOfGroups
{
get { return _maxNumberOfGroups; }
set
{
Debug.Assert(this != Default, "Default instance is supposed to be immutable.");
if (value <= 0 && value != Unbounded) throw new ArgumentOutOfRangeException("value");
_maxNumberOfGroups = value;
}
}
/// <summary>Gets a MaxNumberOfGroups value that may be used for comparison purposes.</summary>
/// <returns>The maximum value, usable for comparison purposes.</returns>
/// <remarks>Unlike MaxNumberOfGroups, this property will always return a positive value.</remarks>
internal Int64 ActualMaxNumberOfGroups
{
get { return (_maxNumberOfGroups == Unbounded) ? Int64.MaxValue : _maxNumberOfGroups; }
}
}
}