Generator Class

Article
06/18/2009

This class is the abstract base class for data generators.

Namespace: Microsoft.Data.Schema.DataGenerator
Assembly: Microsoft.Data.Schema (in Microsoft.Data.Schema.dll)

Syntax

'Declaration
<CLSCompliantAttribute(True)> _
<GeneratorAttribute(GetType(DefaultGeneratorDesigner))> _
Public MustInherit Class Generator _
    Implements IGenerator, IDisposable, IExtensionInformation, IExtension
'Usage
Dim instance As Generator

[CLSCompliantAttribute(true)]
[GeneratorAttribute(typeof(DefaultGeneratorDesigner))]
public abstract class Generator : IGenerator, 
    IDisposable, IExtensionInformation, IExtension

[CLSCompliantAttribute(true)]
[GeneratorAttribute(typeof(DefaultGeneratorDesigner))]
public ref class Generator abstract : IGenerator, 
    IDisposable, IExtensionInformation, IExtension

public abstract class Generator implements IGenerator, IDisposable, IExtensionInformation, IExtension

[<AbstractClassAttribute>]
[<CLSCompliantAttribute(true)>]
[<GeneratorAttribute(typeof(DefaultGeneratorDesigner))>]
type Generator =  
    class
        interface IGenerator
        interface IDisposable
        interface IExtensionInformation
        interface IExtension
    end

Remarks

If the standard data generators are insufficient, you can create custom data generators. To create a custom data generator, you must create a class that implements IGenerator or inherits from Generator. You identify the class as a data generator by decorating it with GeneratorAttribute.

You can create a custom designer for a custom data generator, or you can use DefaultGeneratorDesigner.

The base class implementation constructs outputs that are based on public properties that are marked with the OutputAttribute. The inputs are set by using the InputAttribute. Using properties that are marked with attributes provides a simple mechanism for declaring input and output values that are strongly typed.

Examples

The standard data generators cannot generate data to satisfy some check constraints. For example, a check constraint requires that a date is in one of two distinct ranges. You cannot use the standard DateTime generator. This example creates a custom data generator that can satisfy such a constraint. The generator accepts two distinct ranges as the input and generates a random date that is in one of the two ranges. For more information, see Walkthrough: Creating a Custom Data Generator for a Check Constraint.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.VisualStudio.TeamSystem.Data.DataGenerator;

namespace GeneratorDateRangesCS
{
    public class GeneratorDateRangesCS : Generator
    {
        DateTime mRange1Min;
        DateTime mRange1Max;

        DateTime mRange2Min;
        DateTime mRange2Max;

        [Input]
        public DateTime Range1Min
        {
            set {mRange1Min = value;}
        }

        [Input]
        public DateTime Range1Max
        {
            set {mRange1Max = value;}
        }

        [Input]
        public DateTime Range2Min
        {
            set {mRange2Min = value;}
        }

        [Input]
        public DateTime Range2Max
        {
            set {mRange2Max = value;}
        }


        DateTime mRandomDate;

        [Output]
        public DateTime RandomDate
        {
            get {return mRandomDate;}
        }

        Random mRandom;
        Random mRandomRange;

        protected override void OnInitialize(GeneratorInit initInfo)
        {
            mRandom = new Random(this.Seed);       //deterministic
            mRandomRange = new Random(this.Seed);  //deterministic

            //mRandom = new Random();                //non-deterministic
            //mRandomRange = new Random();           //non-deterministic

            base.OnInitialize(initInfo);
        }


        protected override void OnGenerateNextValues()
        {
            DateTime min;
            DateTime max;

            //Generate a random date from either range 1 or range 2.
            //Randomly select either range 1 or range 2 by randomly 
            //generating an odd or an even random number.
            //------------------------------------------------------------
            if (mRandomRange.Next() % 2 == 0)  //check for odd or even
            {
                min = mRange1Min;
                max = mRange1Max;
            }
            else
            {
                min = mRange2Min;
                max = mRange2Max;
            }

            //The formula for creating a random number in a specific range is:
            //start of range + (size of range * random number between 0 and 1)

            //size of range
            TimeSpan range = max - min;

            //(size of range * random number between 0 and 1)
            TimeSpan randomNumber = new TimeSpan((long)(range.Ticks * mRandom.NextDouble()));

            //start of range + (size of range * random number between 0 and 1)
            mRandomDate = min + randomNumber;
        }
    }//end class
}//end namespace

Imports Microsoft.VisualStudio.TeamSystem.Data.DataGenerator

Public Class GeneratorDateRangesVB
    Inherits Generator

    Dim mRange1Min As Date
    Dim mRange1Max As Date

    Dim mRange2Min As Date
    Dim mRange2Max As Date

    <Input()> _
    Public WriteOnly Property Range1Min() As Date
        Set(ByVal value As Date)
            mRange1Min = value
        End Set
    End Property

    <Input()> _
    Public WriteOnly Property Range1Max() As Date
        Set(ByVal value As Date)
            mRange1Max = value
        End Set
    End Property

    <Input()> _
    Public WriteOnly Property Range2Min() As Date
        Set(ByVal value As Date)
            mRange2Min = value
        End Set
    End Property

    <Input()> _
    Public WriteOnly Property Range2Max() As Date
        Set(ByVal value As Date)
            mRange2Max = value
        End Set
    End Property


    Dim mRandomDate As Date

    <Output()> _
    Public ReadOnly Property RandomDate() As Date
        Get
            Return mRandomDate
        End Get
    End Property


    Dim mRandom As Random
    Dim mRandomRange As Random

    Protected Overrides Sub OnInitialize(ByVal initInfo As GeneratorInit)

        mRandom = New Random(Me.Seed)       'deterministic
        mRandomRange = New Random(Me.Seed)  'deterministic

        'mRandom = New Random()              'non-deterministic
        'mRandomRange = New Random()         'non-deterministic

        MyBase.OnInitialize(initInfo)
    End Sub


    Protected Overrides Sub OnGenerateNextValues()

        Dim min As Date
        Dim max As Date

        'Generate a random date from either range 1 or range 2.
        'Randomly select either range 1 or range 2 by randomly 
        'generating an odd or an even random number.
        '------------------------------------------------------------
        If mRandomRange.Next() Mod 2 = 0 Then  'check for odd or even
            min = mRange1Min
            max = mRange1Max
        Else
            min = mRange2Min
            max = mRange2Max
        End If

        'The formula for creating a random number in a specific range is:
        'start of range + (size of range * random number between 0 and 1)

        'size of range
        Dim range As TimeSpan = max - min

        '(size of range * random number between 0 and 1)
        Dim randomNumber As TimeSpan = New TimeSpan(CLng(range.Ticks * mRandom.NextDouble()))

        'start of range + (size of range * random number between 0 and 1)
        mRandomDate = min + randomNumber

    End Sub
End Class

Inheritance Hierarchy

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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Generator Class

Syntax

Remarks

Examples

Inheritance Hierarchy

Thread Safety

See Also

Reference

Other Resources

Additional resources