Can parallel inheritance be avoided?

[Audriusa83]

I have to develop a recording system. Say, there are multiple records instructing what to check and then checks are performed over the time.
Now in my case records can be two types - Value record (with min and max values specified and check contains the actual value) and Conform record (meaning that check meets the criteria). I was thinking to make abstract record and then inherit Value and Conform records. Then I should have abstract check and inherited Value and Conform checks.

abstract class Record
{
public string Task { get; set; }
public List<Check> Checks { get; set; }
}

class ValueRecord : Record
{
public float MinValue { get; set; }
public float MaxValue { get; set; }
public void AddCheck(ValueCheck item) {
base.Checks.Add(item);
}
}

class ConfromRecord : Record
{
public void AddCheck(ConformCheck item) {
base.Checks.Add(item);
}
}

abstract class Check
{
public DateTime CreatedOn { get; set; }
}

class ValueCheck : Check
{
public float Value { get; set; }
}

class ConformCheck : Check
{
public bool IsConform { get; set; }
}


But this means I have parallel inheritance and if I'll have to change anything, I must change in two places. Is there a better, more loosely way to do it?

 

[stevexff]

When you 'check conformance' does it use the values in the ValueRecord? Should you have composition or possibly the Template pattern here?

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[Audriusa83]

Thanks Steve, I looked up the composite and I think it should fit here well. Something like this perhaps:

class Record
{
public void Record(IRecordType type)
{
this.Type = type;
}
public string Task { get; set; }
public List<Check> Checks { get; set; }
public IRecordType Type { get; private set; }
}

interface IRecordType
{
Check CreateCheck(Record record);
}

class ValueRecord : IRecordType
{
public float MinValue { get; set; }
public float MaxValue { get; set; }
Check CreateCheck(Record record)
{
ValueCheck check=new ValueCheck();
record.Checks.Add(check);
return check;
}
}

class ConfromRecord : IRecordType
{
Check CreateCheck(Record record)
{
ConformCheck check = new ConformCheck();
record.Checks.Add(check);
return check;
}
}

abstract class Check
{
public DateTime CreatedOn { get; set; }
}

class ValueCheck : Check
{
public float Value { get; set; }
}

class ConformCheck : Check
{
public bool IsConform { get; set; }
}


Does it look OK? I'm still trying to nail OOP so feedback would be appreciated.