Validator Pattern

Overview

Each OsidObject has a corresponding OsidObjectValidator that inspects and checks the compliance of an OsidObject. It is used by default in the builder pattern but can be used for any OsidObject before releasing it to an OSID Consumer.

Which checks a validator runs is selected by an EnumSet<Validation>. ALL is the default. The Validation enum enumerates the available check types; passing no enum set applies a default validation.

Validation Checks

Each constant of the Validation enum names one class of check a validator may apply. ALL and NONE select every check or none; the remainder can be combined in any EnumSet.

Value	Definition
`ALL`	all checks
`NONE`	the opposite of ALL
`NULL`	check for any nulls
`NIL_ID`	check for any nil implementations of `Id`
`NIL_TYPE`	check for any nil implementations of `Type`
`NIL_OBJECT`	check for any nil implementations of objects (not implemented)
`RANGE`	check that low/high and min/max ranges are in the right order
`CARDINAL`	check that cardinal numbers are non-negative
`TYPE_SUPPORT`	cross-reference type support
`EMPTY_STRING`	listed in the enumeration but not a check
`ID_CONSISTENCY`	check for consistent `Id`s
`METHOD_SUPPORT`	check for proper method states (basic isActive() and isEnabled() boolean checks)
`TRAVERSE`	traverse nested OsidObjects
`RECORDS`	check for existence of OsidRecords by Type

Javadoc Reference

net.okapia.osid.jamocha.builder.validator

Static Factory Method Pattern

static OsidObject validateOsidObject(EnumSet<Validation> validation, OsidObject object)

Parameter	Type	Description
`validation`	`EnumSet<Validation>`	the set of checks to perform; an overload without this argument applies a default validation
`object`	`OsidObject`	the object to validate

Returns the validated OsidObject unchanged — throws InvalidReturnException, NullReturnException, BadLogicException, or NullArgumentException when a constraint is violated

Example

public org.osid.repository.Asset getAsset(org.osid.id.Id assetId)
    throws org.osid.NotFoundException,
           org.osid.OperationFailedException,
           org.osid.PermissionDeniedFailedException {

    var data = fetch(assetId);
    return (new (AssetValidator.validate(new MyAsset(data));
}

Yes, I run them inline where possible. In most cases it is worth it to blow up where the problem was caused.