com.typesafe.config

Interface ConfigObject

All Superinterfaces:

ConfigMergeable, ConfigValue, java.util.Map<java.lang.String,ConfigValue>

public interface ConfigObject
extends ConfigValue, java.util.Map<java.lang.String,ConfigValue>

Subtype of ConfigValue representing an object (AKA dictionary or map) value, as in JSON's curly brace { "a" : 42 } syntax.

An object may also be viewed as a Config by calling toConfig().

ConfigObject implements java.util.Map<String, ConfigValue> so you can use it like a regular Java map. Or call unwrapped() to unwrap the map to a map with plain Java values rather than ConfigValue.

Like all ConfigValue subtypes, ConfigObject is immutable. This makes it threadsafe and you never have to create "defensive copies." The mutator methods from Map all throw UnsupportedOperationException.

The ConfigValue.valueType() method on an object returns ConfigValueType.OBJECT.

In most cases you want to use the Config interface rather than this one. Call toConfig() to convert a ConfigObject to a Config.

The API for a ConfigObject is in terms of keys, while the API for a Config is in terms of path expressions. Conceptually, ConfigObject is a tree of maps from keys to values, while a Config is a one-level map from paths to values.

Use ConfigUtil.joinPath(java.lang.String...) and ConfigUtil.splitPath(java.lang.String) to convert between path expressions and individual path elements (keys).

A ConfigObject may contain null values, which will have ConfigValue.valueType() equal to ConfigValueType.NULL. If get(Object) returns Java's null then the key was not present in the parsed file (or wherever this value tree came from). If get("key") returns a ConfigValue with type ConfigValueType#NULL then the key was set to null explicitly in the config file.

Do not implement interface ConfigObject; it should only be implemented by the config library. Arbitrary implementations will not work because the library internals assume a specific concrete implementation. Also, this interface is likely to grow new methods over time, so third-party implementations will break.

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Method Summary

Modifier and Type	Method and Description
ConfigValue	get(java.lang.Object key) Gets a ConfigValue at the given key, or returns null if there is no value.
Config	toConfig() Converts this object to a Config instance, enabling you to use path expressions to find values in the object.
java.util.Map<java.lang.String,java.lang.Object>	unwrapped() Recursively unwraps the object, returning a map from String to whatever plain Java values are unwrapped from the object's values.
ConfigObject	withFallback(ConfigMergeable other) Returns a new value computed by merging this value with another, with keys in this value "winning" over the other one.
ConfigObject	withOnlyKey(java.lang.String key) Clone the object with only the given key (and its children) retained; all sibling keys are removed.
ConfigObject	withOrigin(ConfigOrigin origin) Returns a ConfigValue based on this one, but with the given origin.
ConfigObject	withoutKey(java.lang.String key) Clone the object with the given key removed.
ConfigObject	withValue(java.lang.String key, ConfigValue value) Returns a ConfigObject based on this one, but with the given key set to the given value.

Methods inherited from interface com.typesafe.config.ConfigValue

atKey, atPath, origin, render, render, valueType

Methods inherited from interface java.util.Map

clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

Method Detail

toConfig

toConfig()

Converts this object to a Config instance, enabling you to use path expressions to find values in the object. This is a constant-time operation (it is not proportional to the size of the object).

Returns:

a Config with this object as its root

unwrapped

java.util.Map<java.lang.String,java.lang.Object> unwrapped()

Recursively unwraps the object, returning a map from String to whatever plain Java values are unwrapped from the object's values.

Specified by:

unwrapped in interface ConfigValue

Returns:

a Map containing plain Java objects

withFallback

withFallback(ConfigMergeable other)

Description copied from interface: ConfigMergeable

Returns a new value computed by merging this value with another, with keys in this value "winning" over the other one.

This associative operation may be used to combine configurations from multiple sources (such as multiple configuration files).

The semantics of merging are described in the spec for HOCON. Merging typically occurs when either the same object is created twice in the same file, or two config files are both loaded. For example:

  foo = { a: 42 }
  foo = { b: 43 }
 

Here, the two objects are merged as if you had written:

  foo = { a: 42, b: 43 }
 

Only ConfigObject and Config instances do anything in this method (they need to merge the fallback keys into themselves). All other values just return the original value, since they automatically override any fallback. This means that objects do not merge "across" non-objects; if you write object.withFallback(nonObject).withFallback(otherObject), then otherObject will simply be ignored. This is an intentional part of how merging works, because non-objects such as strings and integers replace (rather than merging with) any prior value:

 foo = { a: 42 }
 foo = 10
 

Here, the number 10 "wins" and the value of foo would be simply 10. Again, for details see the spec.

Specified by:

withFallback in interface ConfigMergeable

Specified by:

withFallback in interface ConfigValue

Parameters:

other - an object whose keys should be used as fallbacks, if the keys are not present in this one

Returns:

a new object (or the original one, if the fallback doesn't get used)

get

get(java.lang.Object key)

Gets a ConfigValue at the given key, or returns null if there is no value. The returned ConfigValue may have ConfigValueType.NULL or any other type, and the passed-in key must be a key in this object (rather than a path expression).

Specified by:

get in interface java.util.Map<java.lang.String,ConfigValue>

Parameters:

key - key to look up

Returns:

the value at the key or null if none

withOnlyKey

withOnlyKey(java.lang.String key)

Clone the object with only the given key (and its children) retained; all sibling keys are removed.

Parameters:

key - key to keep

Returns:

a copy of the object minus all keys except the one specified

withoutKey

withoutKey(java.lang.String key)

Clone the object with the given key removed.

Parameters:

key - key to remove

Returns:

a copy of the object minus the specified key

withValue

withValue(java.lang.String key,
                       ConfigValue value)

Returns a ConfigObject based on this one, but with the given key set to the given value. Does not modify this instance (since it's immutable). If the key already has a value, that value is replaced. To remove a value, use withoutKey(String).

Parameters:

key - key to add

value - value at the new key

Returns:

the new instance with the new map entry

withOrigin

withOrigin(ConfigOrigin origin)

Description copied from interface: ConfigValue

Returns a ConfigValue based on this one, but with the given origin. This is useful when you are parsing a new format of file or setting comments for a single ConfigValue.

Specified by:

withOrigin in interface ConfigValue

Parameters:

origin - the origin set on the returned value

Returns:

the new ConfigValue with the given origin