public boolean exist(String key) {
		String value = this.properties.getProperty(key);
		if (value != null) {
			return true;
		}

		List<String> keys = propertiesKeyMapper.getKeys(key);
		if (keys != null && !keys.isEmpty()) {
			for (String each : keys) {
				value = this.properties.getProperty(each);
				if (value != null) {
					return true;
				}
			}
		}
		return false;
	}
Constructor.

@param properties {@link Properties} which will be used for data retrieval.
ngrinder-core/src/main/java/org/ngrinder/common/util/PropertiesWrapper.java