# Poco::Util

# class AbstractConfiguration

Library: Util
Package: Configuration
Header: Poco/Util/AbstractConfiguration.h

## Description

AbstractConfiguration is an abstract base class for different kinds of configuration data, such as INI files, property files, XML configuration files or the Windows Registry.

Configuration property keys have a hierarchical format, consisting of names separated by periods. The exact interpretation of key names is up to the actual subclass implementation of AbstractConfiguration. Keys are case sensitive.

All public methods are synchronized, so the class is safe for multithreaded use. AbstractConfiguration implements reference counting based garbage collection.

Subclasses must override the getRaw(), setRaw() and enumerate() methods.

## Inheritance

Direct Base Classes: Poco::RefCountedObject

All Base Classes: Poco::RefCountedObject

Known Derived Classes: ConfigurationMapper, ConfigurationView, FilesystemConfiguration, IniFileConfiguration, LayeredConfiguration, MapConfiguration, PropertyFileConfiguration, SystemConfiguration, WinRegistryConfiguration, XMLConfiguration

## Member Summary

Member Functions: createView, enableEvents, enumerate, eventsEnabled, expand, getBool, getDouble, getInt, getRaw, getRawString, getString, has, hasOption, hasProperty, keys, parseBool, parseInt, remove, removeRaw, setBool, setDouble, setInt, setRaw, setRawWithEvent, setString

Inherited Functions: duplicate, referenceCount, release

## Nested Classes

### class KeyValue

A key-value pair, used as event argument.

## Types

### Keys

typedef std::vector < std::string > Keys;

## Constructors

### AbstractConfiguration

AbstractConfiguration();

Creates the AbstractConfiguration.

## Destructor

### ~AbstractConfiguration

virtual ~AbstractConfiguration();

## Member Functions

### createView

const AbstractConfiguration * createView(
const std::string & prefix
) const;

Creates a non-mutable view (see ConfigurationView) into the configuration.

### createView

AbstractConfiguration * createView(
const std::string & prefix
);

Creates a view (see ConfigurationView) into the configuration.

### enableEvents

void enableEvents(
bool enable = true
);

Enables (or disables) events.

### eventsEnabled

bool eventsEnabled() const;

Returns true if and only if events are enabled.

### expand

std::string expand(
const std::string & value
) const;

Replaces all occurences of ${<property>} in value with the value of the <property>. If <property> does not exist, nothing is changed.

If a circular property reference is detected, a CircularReferenceException will be thrown.

### getBool

bool getBool(
const std::string & key
) const;

Returns the boolean value of the property with the given name. Throws a NotFoundException if the key does not exist. Throws a SyntaxException if the property can not be converted to a boolean. If the value contains references to other properties (${<property>}), these are expanded.

### getBool

bool getBool(
const std::string & key,
bool defaultValue
) const;

If a property with the given key exists, returns the property's boolean value, otherwise returns the given default value. Throws a SyntaxException if the property can not be converted to a boolean. The following string values can be converted into a boolean:

- numerical values: non zero becomes true, zero becomes false
- strings: true, yes, on become true, false, no, off become false

Case does not matter. If the value contains references to other properties (${<property>}), these are expanded.

### getDouble

double getDouble(
const std::string & key
) const;

Returns the double value of the property with the given name. Throws a NotFoundException if the key does not exist. Throws a SyntaxException if the property can not be converted to a double. If the value contains references to other properties (${<property>}), these are expanded.

### getDouble

double getDouble(
const std::string & key,
double defaultValue
) const;

If a property with the given key exists, returns the property's double value, otherwise returns the given default value. Throws a SyntaxException if the property can not be converted to an double. If the value contains references to other properties (${<property>}), these are expanded.

### getInt

int getInt(
const std::string & key
) const;

Returns the int value of the property with the given name. Throws a NotFoundException if the key does not exist. Throws a SyntaxException if the property can not be converted to an int. Numbers starting with 0x are treated as hexadecimal. If the value contains references to other properties (${<property>}), these are expanded.

### getInt

int getInt(
const std::string & key,
int defaultValue
) const;

If a property with the given key exists, returns the property's int value, otherwise returns the given default value. Throws a SyntaxException if the property can not be converted to an int. Numbers starting with 0x are treated as hexadecimal. If the value contains references to other properties (${<property>}), these are expanded.

### getRawString

std::string getRawString(
const std::string & key
) const;

Returns the raw string value of the property with the given name. Throws a NotFoundException if the key does not exist. References to other properties are not expanded.

### getRawString

std::string getRawString(
const std::string & key,
const std::string & defaultValue
) const;

If a property with the given key exists, returns the property's raw string value, otherwise returns the given default value. References to other properties are not expanded.

### getString

std::string getString(
const std::string & key
) const;

Returns the string value of the property with the given name. Throws a NotFoundException if the key does not exist. If the value contains references to other properties (${<property>}), these are expanded.

### getString

std::string getString(
const std::string & key,
const std::string & defaultValue
) const;

If a property with the given key exists, returns the property's string value, otherwise returns the given default value. If the value contains references to other properties (${<property>}), these are expanded.

### has

bool has(
const std::string & key
) const;

Returns true if and only if the property with the given key exists.

Same as hasProperty().

### hasOption

bool hasOption(
const std::string & key
) const;

Returns true if and only if the property with the given key exists.

Same as hasProperty().

### hasProperty

bool hasProperty(
const std::string & key
) const;

Returns true if and only if the property with the given key exists.

### keys

void keys(
Keys & range
) const;

Returns in range the names of all keys at root level.

### keys

void keys(
const std::string & key,
Keys & range
) const;

Returns in range the names of all subkeys under the given key. If an empty key is passed, all root level keys are returned.

### remove

void remove(
const std::string & key
);

Removes the property with the given key.

Does nothing if the key does not exist.

### setBool

void setBool(
const std::string & key,
bool value
);

Sets the property with the given key to the given value. An already existing value for the key is overwritten.

### setDouble

void setDouble(
const std::string & key,
double value
);

Sets the property with the given key to the given value. An already existing value for the key is overwritten.

### setInt

void setInt(
const std::string & key,
int value
);

Sets the property with the given key to the given value. An already existing value for the key is overwritten.

### setString

void setString(
const std::string & key,
const std::string & value
);

Sets the property with the given key to the given value. An already existing value for the key is overwritten.

### enumerate

virtual void enumerate(
const std::string & key,
Keys & range
) const = 0;

Returns in range the names of all subkeys under the given key. If an empty key is passed, all root level keys are returned.

### getRaw

virtual bool getRaw(
const std::string & key,
std::string & value
) const = 0;

If the property with the given key exists, stores the property's value in value and returns true. Otherwise, returns false.

Must be overridden by subclasses.

### parseBool

static bool parseBool(
const std::string & value
);

### parseInt

static int parseInt(
const std::string & value
);

### removeRaw

virtual void removeRaw(
const std::string & key
);

Removes the property with the given key.

Does nothing if the key does not exist.

Should be overridden by subclasses; the default implementation throws a Poco::NotImplementedException.

### setRaw

virtual void setRaw(
const std::string & key,
const std::string & value
) = 0;

Sets the property with the given key to the given value. An already existing value for the key is overwritten.

Must be overridden by subclasses.

### setRawWithEvent

void setRawWithEvent(
const std::string & key,
std::string value
);

## Variables

### propertyChanged

Poco::BasicEvent < const KeyValue > propertyChanged;

Fired after a property value has been changed or a property has been created.

### propertyChanging

Poco::BasicEvent < KeyValue > propertyChanging;

Fired before a property value is changed or a new property is created.

Can be used to check or fix a property value, or to cancel the change by throwing an exception.

The event delegate can use one of the get...() functions to obtain the current property value.

### propertyRemoved

Poco::BasicEvent < const std::string > propertyRemoved;

Fired after a property has been removed by a call to remove().

### propertyRemoving

Poco::BasicEvent < const std::string > propertyRemoving;

Fired before a property is removed by a call to remove().

Note: This will even be fired if the key does not exist and the remove operation will fail with an exception.