OSID - osid.course.requisite.CredentialRequirement Service Interface Definition

Interface	osid.course.requisite.CredentialRequirement
Implements	`osid.OsidRule`
Implements	`osid.Aggregateable`
Description	A `CredentialRequirement` is an `OsidRule` and represents a requirement based on a `Credential.`
Method	getAltRequisites
Description	Gets any `Requisites` that may be substituted in place of this `CredentialRequirement.` All `Requisites` must be satisifed to be a substitute for this credential requirement. Inactive `Requisites` are not evaluated but if no applicable requisite exists, then the alternate requisite is not satisifed.
Return	`osid.course.requisite.Requisite[]`		the alternate requisites
Compliance	`mandatory`		This method must be implemented.
Method	getCredentialId
Description	Gets the `Id` of the `Credential.`
Return	`osid.id.Id`		the credential `Id`
Compliance	`mandatory`		This method must be implemented.
Method	getCredential
Description	Gets the `Credential.`
Return	`osid.course.program.Credential`		the credential
Errors	OPERATION_FAILED		unable to complete request
Compliance	`mandatory`		This method must be implemented.
Method	hasTimeframe
Description	Tests if the credential has to be earned within the required duration.
Return	`boolean`		`true` if the credential must be earned within a required time, `false` if it could have been earned at any time in the past
Compliance	`mandatory`		This method must be implemented.
Method	getTimeframe
Description	Gets the timeframe in which the credential has to be earned. A negative duration indicates the credential had to be earned within the specified amount of time in the past. A posiitive duration indicates the credential must be earned within the specified amount of time in the future. A zero duration indicates the credential must be earned in the current term.
Return	`osid.calendaring.Duration`		the time frame
Errors	ILLEGAL_STATE		`hasTimeframe()` is `false`
Compliance	`mandatory`		This method must be implemented.
Method	getCredentialRequirementRecord
Description	Gets the credential requirement record corresponding to the given `CredentialRequirement` record `Type.` This method is used to retrieve an object implementing the requested record. The `credentialRequirementRecordType` may be the `Type` returned in `getRecordTypes()` or any of its parents in a `Type` hierarchy where `hasRecordType(credentialRequirementRecordType)` is `true` .
Parameters	`osid.type.Type`	`credentialRequirementRecordType`	the type of credential requirement record to retrieve
Return	`osid.course.requisite.records.CredentialRequirementRecord`		the credential requirement record
Errors	NULL_ARGUMENT		`credentialRequirementRecordType` is `null`
	OPERATION_FAILED		unable to complete request
	UNSUPPORTED		`hasRecordType(credentialRequirementRecordType)` is `false`
Compliance	`mandatory`		This method must be implemented.