class BuildTimestampValueSource extends AbstractValueSource {
    private final Date startTime;
    private final Map<String, String> properties;

    BuildTimestampValueSource(Date startTime, Map<String, String> properties) {
        super(false);
        this.startTime = startTime;
        this.properties = properties;
    }

    @Override
    public Object getValue(String expression) {<FILL_FUNCTION_BODY>}
}

        if ("build.timestamp".equals(expression) || "maven.build.timestamp".equals(expression)) {
            return new MavenBuildTimestamp(startTime, properties).formattedTimestamp();
        }
        return null;
    
<no_super_class>