public IncludeCacheValidity(SourceResolver resolver) 
{
        this.resolver = resolver;
        sources = new ArrayList();
        timeStamps = new ArrayList();
        isNew = true;
}

 public  void add(String source,
    long timeStamp) 
{
        this.sources.add(source);
        this.timeStamps.add(new Long(timeStamp));
}

 public boolean isNew() 
{
        return isNew;
}

 public boolean isValid(CacheValidity validity) 
{
        if (validity instanceof IncludeCacheValidity) {
            SourceResolver otherResolver = ((IncludeCacheValidity) validity).resolver;
            for(Iterator i = sources.iterator(), j = timeStamps.iterator(); i.hasNext();) {
                String src = ((String)i.next());
                long timeStamp = ((Long)j.next()).longValue();
                Source otherSource = null;
                try {
                    otherSource = otherResolver.resolveURI(src);
                    if(otherSource.getLastModified() != timeStamp ||
                        timeStamp == 0)
                        return false;
                } catch (Exception e) {
                    return false;
                } finally {
                    otherResolver.release(otherSource);
                }
            }
            return true;
        }
        return false;
}

 public  void setIsNew2False() 
{
        isNew = false;
        resolver = null;
}

 public String toString() 
{
        StringBuffer b = new StringBuffer("Include Validity[");
        for(Iterator i = sources.iterator(), j = timeStamps.iterator(); i.hasNext();) {
            b.append('{");
            b.append(i.next());
            b.append(':");
            b.append(j.next());
            b.append('}");
            if(i.hasNext()) b.append(':");
        }
        b.append(']");
        return b.toString();
}