Package io.github.ajevans.dbcode.utilities

Class PropertiesSingleton

java.lang.Object

java.util.Dictionary<K,V>

java.util.Hashtable<Object,Object>

java.util.Properties

io.github.ajevans.dbcode.utilities.PropertiesSingleton

All Implemented Interfaces:

Serializable, Cloneable, Map<Object,Object>

public final class PropertiesSingleton
extends Properties

Singleton to hold all the properties files associated with an application.

Having this as a singleton cuts down on class coupling and makes default properties available in testing.

Set up the singleton by calling addProperties one or more times with a properties file. You can then call the standard Properties methods on its instance, e.g.

String value = PropertiesSingleton.getInstance().getProperty("key");

Author:

Andy Evans

See Also:

Properties, Serialized Form

Version: 1.0 01 Mar 2021

Field Summary

Fields

Modifier and Type	Field	Description
private static PropertiesSingleton	instance	Lazy initialization instance object.

Fields inherited from class java.util.Properties

defaults

Constructor Summary

Constructors

Modifier	Constructor	Description
private	PropertiesSingleton()	Default constructor set to private in line with singleton pattern.

Method Summary

Modifier and Type	Method	Description
void	addProperties(String propertiesFilePath)	Add a file of properties to the singleton.
static PropertiesSingleton	getInstance()	Method to get instance in line with singleton pattern.
void	setDefaults(Properties defaults)	Sets a default set of properties.

Methods inherited from class java.util.Properties

clear, clone, compute, computeIfAbsent, computeIfPresent, contains, containsKey, containsValue, elements, entrySet, equals, forEach, get, getOrDefault, getProperty, getProperty, hashCode, isEmpty, keys, keySet, list, list, load, load, loadFromXML, merge, propertyNames, put, putAll, putIfAbsent, rehash, remove, remove, replace, replace, replaceAll, save, setProperty, size, store, store, storeToXML, storeToXML, storeToXML, stringPropertyNames, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

instance

private static PropertiesSingleton instance

Lazy initialization instance object.

Constructor Details

PropertiesSingleton

private PropertiesSingleton()

Default constructor set to private in line with singleton pattern.

Method Details

getInstance

public static PropertiesSingleton getInstance()

Method to get instance in line with singleton pattern.

Returns:

PropertiesSingleton Single instance of this class.

addProperties

public void addProperties(String propertiesFilePath)
                   throws IOException

Add a file of properties to the singleton.

Parameters:

propertiesFilePath - Properties file to read.

Throws:

IOException - If the file isn't found, though there is the opportunity to load defaults later through setDefaults.

setDefaults

public void setDefaults(Properties defaults)

Sets a default set of properties.

We can't use the usual way of setting these via the constructor.

Parameters:

defaults - Default values to add where missing. If the key already exists, the default will not be used.