co.codewizards.cloudstore.core.config

Class Config

java.lang.Object

co.codewizards.cloudstore.core.config.Config

public class Config
extends Object

Configuration of CloudStore supporting inheritance of settings.

There is one Config instance available (lazily created, cached temporarily) for every directory and every file in a repository. Each Config inherits the settings from the parent-directory, if not explicitly overwritten.

The configuration is based on Properties files. Every property file is optional. If it does not exist, all settings are inherited. If it does exist, only those properties contained in the file are overriden. All properties not contained in the file are still inherited. Inheritance is thus applicable on every individual property.

Modifications, deletions, creations of properties files are detected during runtime (pretty immediately). Note, that this detection is based on the files' timestamps. Since most file systems have a granularity of 1 second (some even 2) for the last-modified-timestamp, multiple modifications in the same second might not be detected.

There is a global properties file in the user's home directory (or wherever ConfigDir points to): /home/tomcat/.cloudstore/cloudstore.properties

Additionally, every directory can optionally contain the following files:

1. .cloudstore.properties
2. cloudstore.properties
3. .${anyFileName}.cloudstore.properties
4. ${anyFileName}.cloudstore.properties

The files 1. and 2. are applicable to the entire directory and all sub-directories and files in it. Usually, on GNU/Linux people will prefer 1., but when using Windows, files starting with a "." are sometimes a bit hard to deal with. Therefore, we support both. The file 2. overrides the settings of file 1..

The files 3. and 4. are applicable only to the file ${anyFileName}. Thus, if you want to set special behaviour for the file example.db only, you can create the file .example.db.cloudstore.properties in the same directory.

Author:

Marco หงุ่ยตระกูล-Schulze - marco at codewizards dot co

Field Summary

Fields

Modifier and Type	Field and Description
protected File[]	propertiesFiles
static String	SYSTEM_PROPERTY_PREFIX Prefix used for system properties overriding configuration entries.

Method Summary

Methods

Modifier and Type	Method and Description
protected File	getFile() Get the directory or file for which this Config instance is responsible.
static Config	getInstance() Gets the global Config for the current user.
static Config	getInstanceForDirectory(File directory) Gets the Config for the given directory.
static Config	getInstanceForFile(File file) Gets the Config for the given file.
String	getProperty(String key, String defaultValue) Gets the property identified by the given key.
boolean	getPropertyAsBoolean(String key, boolean defaultValue)
<E extends Enum<E>> E	getPropertyAsEnum(String key, Class<E> enumClass, E defaultValue) Gets the property identified by the given key.
<E extends Enum<E>> E	getPropertyAsEnum(String key, E defaultValue) Gets the property identified by the given key.
int	getPropertyAsInt(String key, int defaultValue)
long	getPropertyAsLong(String key, long defaultValue)
String	getPropertyAsNonEmptyTrimmedString(String key, String defaultValue) Gets the property identified by the given key; trimmed.
int	getPropertyAsPositiveOrZeroInt(String key, int defaultValue)
long	getPropertyAsPositiveOrZeroLong(String key, long defaultValue)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SYSTEM_PROPERTY_PREFIX

public static final String SYSTEM_PROPERTY_PREFIX

Prefix used for system properties overriding configuration entries.

Every property in the configuration (i.e. in its properties files) can be overridden by a corresponding system property. The system property must be prefixed.

For example, to override the configuration property with the key "deferrableExecutor.timeout", you can pass the system property "cloudstore.deferrableExecutor.timeout" to the JVM. If the system property exists, the configuration is not consulted, but the system property value is used as shortcut.

See Also:

Constant Field Values

propertiesFiles

protected final File[] propertiesFiles

Method Detail

getFile

protected File getFile()

Get the directory or file for which this Config instance is responsible.

Returns:

the directory or file for which this Config instance is responsible. Might be null, if already garbage-collected or if this is the root-parent-Config. We try to make garbage-collection extremely unlikely as long as the Config is held in memory.

getInstance

public static Config getInstance()

Gets the global Config for the current user.

Returns:

the global Config for the current user. Never null.

getInstanceForDirectory

public static Config getInstanceForDirectory(File directory)

Gets the Config for the given directory.

Parameters:

directory - a directory inside a repository. Must not be null. The directory does not need to exist (it may be created later).

Returns:

the Config for the given directory. Never null.

getInstanceForFile

public static Config getInstanceForFile(File file)

Gets the Config for the given file.

Parameters:

file - a file inside a repository. Must not be null. The file does not need to exist (it may be created later).

Returns:

the Config for the given file. Never null.

getProperty

public String getProperty(String key,
                 String defaultValue)

Gets the property identified by the given key.

This method directly delegates to Properties.getProperty(String, String). Thus, an empty String in the internal Properties is returned instead of the given defaultValue. The defaultValue is only returned, if neither the internal Properties of this Config nor any of its parents contains the entry.

Important: This is often not the desired behaviour. You might want to use getPropertyAsNonEmptyTrimmedString(String, String) instead!

Every property can be overwritten by a system property prefixed with "cloudstore.". If - for example - the key "updater.force" is to be read and a system property named "cloudstore.updater.force" is set, this system property is returned instead!

Parameters:

key - the key identifying the property. Must not be null.

defaultValue - the default value to fall back to, if neither this Config's internal Properties nor any of its parents contains a matching entry. May be null.

Returns:

the property's value. Never null unless defaultValue is null.

See Also:

getPropertyAsNonEmptyTrimmedString(String, String)

getPropertyAsNonEmptyTrimmedString

public String getPropertyAsNonEmptyTrimmedString(String key,
                                        String defaultValue)

Gets the property identified by the given key; trimmed.

In contrast to getProperty(String, String), this method falls back to the given defaultValue, if the internal Properties contains an empty String (after trimming) as value for the given key.

It therefore means that a value set to an empty String in the properties file means to use the program's default instead. It is therefore consistent with getPropertyAsLong(String, long) and all other getPropertyAs...(...) methods.

Every property can be overwritten by a system property prefixed with "cloudstore.". If - for example - the key "updater.force" is to be read and a system property named "cloudstore.updater.force" is set, this system property is returned instead!

Parameters:

key - the key identifying the property. Must not be null.

defaultValue - the default value to fall back to, if neither this Config's internal Properties nor any of its parents contains a matching entry or if this entry's value is an empty String. May be null.

Returns:

the property's value. Never null unless defaultValue is null.

getPropertyAsLong

public long getPropertyAsLong(String key,
                     long defaultValue)

getPropertyAsPositiveOrZeroLong

public long getPropertyAsPositiveOrZeroLong(String key,
                                   long defaultValue)

getPropertyAsInt

public int getPropertyAsInt(String key,
                   int defaultValue)

getPropertyAsPositiveOrZeroInt

public int getPropertyAsPositiveOrZeroInt(String key,
                                 int defaultValue)

getPropertyAsEnum

public <E extends Enum<E>> E getPropertyAsEnum(String key,
                                      E defaultValue)

Gets the property identified by the given key.

Parameters:

key - the key identifying the property. Must not be null.

defaultValue - the default value to fall back to, if neither this Config's internal Properties nor any of its parents contains a matching entry or if this entry's value does not match any possible enum value. Must not be null. If a null default value is required, use getPropertyAsEnum(String, Class, Enum) instead!

Returns:

the property's value. Never null.

See Also:

getPropertyAsEnum(String, Class, Enum), getPropertyAsNonEmptyTrimmedString(String, String)

getPropertyAsEnum

public <E extends Enum<E>> E getPropertyAsEnum(String key,
                                      Class<E> enumClass,
                                      E defaultValue)

Gets the property identified by the given key.

Parameters:

key - the key identifying the property. Must not be null.

enumClass - the enum's type. Must not be null.

defaultValue - the default value to fall back to, if neither this Config's internal Properties nor any of its parents contains a matching entry or if this entry's value does not match any possible enum value. May be null.

Returns:

the property's value. Never null unless defaultValue is null.

See Also:

getPropertyAsEnum(String, Enum), getPropertyAsNonEmptyTrimmedString(String, String)

getPropertyAsBoolean

public boolean getPropertyAsBoolean(String key,
                           boolean defaultValue)