Class Poco::Util::LayeredConfiguration
Author: Applied Informatics Software Engineering GmbH and Contributors

# Poco::Util

# class LayeredConfiguration

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

## Description

A LayeredConfiguration consists of a number of AbstractConfigurations.

When reading a configuration property in a LayeredConfiguration, all added configurations are searched, in order of their priority. Configurations with lower priority values have precedence.

When setting a property, the property is always written to the first writeable configuration (see addWriteable()). If no writeable configuration has been added to the LayeredConfiguration, and an attempt is made to set a property, a RuntimeException is thrown.

Every configuration added to the LayeredConfiguration has a priority value. The priority determines the position where the configuration is inserted, with lower priority values coming before higher priority values.

If no priority is specified, a priority of 0 is assumed.

## Inheritance

Direct Base Classes: AbstractConfiguration

All Base Classes: Poco::RefCountedObject, AbstractConfiguration

## Member Summary

Member Functions: add, addFront, addWriteable, enumerate, find, getRaw, highest, insert, lowest, removeConfiguration, removeRaw, setRaw

Inherited Functions: createView, duplicate, enableEvents, enumerate, eventsEnabled, expand, getBool, getDouble, getInt, getInt64, getRaw, getRawString, getString, getUInt, getUInt64, has, hasOption, hasProperty, keys, parseBool, parseInt, parseInt64, parseUInt, parseUInt64, referenceCount, release, remove, removeRaw, setBool, setDouble, setInt, setInt64, setRaw, setRawWithEvent, setString, setUInt, setUInt64

## Nested Classes

### struct ConfigItem

## Types

### ConfigPtr

typedef Poco::AutoPtr < AbstractConfiguration > ConfigPtr;

## Constructors

### LayeredConfiguration

LayeredConfiguration();

Creates the LayeredConfiguration.

## Destructor

### ~LayeredConfiguration

~LayeredConfiguration();

## Member Functions

### add

void add(
AbstractConfiguration * pConfig
);

Adds a read-only configuration to the back of the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### add

void add(
AbstractConfiguration * pConfig,
const std::string & label
);

Adds a read-only configuration with the given label to the back of the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### add

void add(
AbstractConfiguration * pConfig,
bool shared
);

Adds a read-only configuration to the back of the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### add

void add(
AbstractConfiguration * pConfig,
const std::string & label,
bool shared
);

Adds a read-only configuration with the given label to the back of the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### add

void add(
AbstractConfiguration * pConfig,
int priority
);

Adds a read-only configuration to the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### add

void add(
AbstractConfiguration * pConfig,
const std::string & label,
int priority
);

Adds a read-only configuration with the given label to the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### add

void add(
AbstractConfiguration * pConfig,
int priority,
bool shared
);

Adds a read-only configuration the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### add

void add(
AbstractConfiguration * pConfig,
const std::string & label,
int priority,
bool shared
);

Adds a read-only configuration with the given label the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### add

void add(
AbstractConfiguration * pConfig,
int priority,
bool writeable,
bool shared
);

Adds a configuration to the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### add

void add(
AbstractConfiguration * pConfig,
const std::string & label,
int priority,
bool writeable,
bool shared
);

Adds a configuration with the given label to the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### addFront

void addFront(
AbstractConfiguration * pConfig
);

Deprecated. This function is deprecated and should no longer be used.

Adds a read-only configuration to the front of the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### addFront

void addFront(
AbstractConfiguration * pConfig,
bool shared
);

Deprecated. This function is deprecated and should no longer be used.

Adds a read-only configuration to the front of the LayeredConfiguration. If shared is true, the LayeredConfiguration takes ownership of the given configuration.

### addWriteable

void addWriteable(
AbstractConfiguration * pConfig,
int priority
);

Adds a writeable configuration to the LayeredConfiguration. The LayeredConfiguration does not take ownership of the given configuration. In other words, the configuration's reference count is incremented.

### addWriteable

void addWriteable(
AbstractConfiguration * pConfig,
int priority,
bool shared
);

Adds a writeable configuration to the LayeredConfiguration. If shared is false, the LayeredConfiguration takes ownership of the given configuration (and the configuration's reference count remains unchanged).

### find

ConfigPtr find(
const std::string & label
) const;

Finds and returns the configuration with the given label.

Returns null if no such configuration can be found.

### removeConfiguration

void removeConfiguration(
AbstractConfiguration * pConfig
);

Removes the given configuration from the LayeredConfiguration.

Does nothing if the given configuration is not part of the LayeredConfiguration.

### enumerate

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

See also: Poco::Util::AbstractConfiguration::enumerate()

### getRaw

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

See also: Poco::Util::AbstractConfiguration::getRaw()

### highest

int highest() const;

### insert

void insert(
const ConfigItem & item
);

### lowest

int lowest() const;

### removeRaw

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

See also: Poco::Util::AbstractConfiguration::removeRaw()

### setRaw

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

See also: Poco::Util::AbstractConfiguration::setRaw()