org.apache.excalibur.source
Interface SourceValidity

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

AbstractAggregatedValidity, AggregatedValidity, DeferredAggregatedValidity, ExpiresValidity, FileTimeStampValidity, NOPValidity, TimeStampValidity

public interface SourceValidity

extends java.io.Serializable

A SourceValidity object contains all information to check if a Source object is still valid.

There are two possibilities:

• The validity object has all information to check by itself if it is valid (e.g. given an expires date).
• The validity object possibility needs another (newer) validity object to compare against (e.g. to test a last modification date).

To avoid testing what the actual implementation of the validity object supports, the invocation order is to first call isValid() and only if this result is 0 (i.e. "don't know"), then to call isValid(SourceValidity).

Remember to call isValid(SourceValidity) when isValid() returned 0 !

Version:

CVS $Revision: 1.4 $ $Date: 2004/02/28 11:47:26 $

Author:

Avalon Development Team

Field Summary

static int	INVALID
static int	UNKNOWN
static int	UNKNWON Deprecated. because it has been misspelled, use UNKNOWN of course
static int	VALID

Method Summary

int	isValid() Check if the component is still valid.
int	isValid(SourceValidity newValidity) Check if the component is still valid.

Field Detail

VALID

public static final int VALID

See Also:

Constant Field Values

INVALID

public static final int INVALID

See Also:

Constant Field Values

UNKNWON

public static final int UNKNWON

Deprecated. because it has been misspelled, use UNKNOWN of course

See Also:

Constant Field Values

UNKNOWN

public static final int UNKNOWN

See Also:

Constant Field Values

Method Detail

isValid

public int isValid()

Check if the component is still valid. The possible results are :

• -1: invalid. The component isn't valid anymore.
• 0: don't know. This validity should be checked against a new validity object using isValid(SourceValidity).
• 1: valid. The component is still valid.

isValid

public int isValid(SourceValidity newValidity)

Check if the component is still valid. This is only true if the incoming Validity is of the same type and has the "same" values.

The invocation order is that the isValid method of the old Validity object is called with the new one as a parameter.

Returns:

-1 is returned, if the validity object is not valid anymore +1 is returned, if the validity object is still valid 0 is returned, if the validity check could not be performed. In this case, the new validity object is not usable. Examples for this are: when the validity objects have different types, or when one validity object for any reason is not able to get the required information.