return userProperties;
    }

    @Override
    public Properties getExecutionProperties() {
        return executionProperties;
    }

    @Override
    public ProjectBuilderConfiguration setExecutionProperties(Properties executionProperties) {
        this.executionProperties = executionProperties;
        return this;
    }

    @Override
    public Date getBuildStartTime() {
        return buildStartTime;

        Properties props = new Properties();
        props.putAll(context);

        return interpolate(model, null, new DefaultProjectBuilderConfiguration().setExecutionProperties(props), true);
    }

    @Override
    public Model interpolate(Model model, File projectDir, ProjectBuilderConfiguration config, boolean debugEnabled)
            throws ModelInterpolationException {