Interface ConfigObject
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- All Superinterfaces:
ConfigMergeable
,ConfigValue
,java.util.Map<java.lang.String,ConfigValue>
public interface ConfigObject extends ConfigValue, java.util.Map<java.lang.String,ConfigValue>
Subtype ofConfigValue
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 callingtoConfig()
.ConfigObject
implementsjava.util.Map<String, ConfigValue>
so you can use it like a regular Java map. Or callunwrapped()
to unwrap the map to a map with plain Java values rather thanConfigValue
.Like all
ConfigValue
subtypes,ConfigObject
is immutable. This makes it threadsafe and you never have to create "defensive copies." The mutator methods fromMap
all throwUnsupportedOperationException
.The
ConfigValue.valueType()
method on an object returnsConfigValueType.OBJECT
.In most cases you want to use the
Config
interface rather than this one. CalltoConfig()
to convert aConfigObject
to aConfig
.The API for a
ConfigObject
is in terms of keys, while the API for aConfig
is in terms of path expressions. Conceptually,ConfigObject
is a tree of maps from keys to values, while aConfig
is a one-level map from paths to values.Use
ConfigUtil.joinPath(java.lang.String...)
andConfigUtil.splitPath(java.lang.String)
to convert between path expressions and individual path elements (keys).A
ConfigObject
may contain null values, which will haveConfigValue.valueType()
equal toConfigValueType.NULL
. Ifget(Object)
returns Java's null then the key was not present in the parsed file (or wherever this value tree came from). Ifget("key")
returns aConfigValue
with typeConfigValueType#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.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description ConfigValue
get(java.lang.Object key)
Gets aConfigValue
at the given key, or returns null if there is no value.Config
toConfig()
Converts this object to aConfig
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 aConfigValue
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 aConfigObject
based on this one, but with the given key set to the given value.
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Method Detail
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toConfig
Config toConfig()
Converts this object to aConfig
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
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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 interfaceConfigValue
- Returns:
- a
Map
containing plain Java objects
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withFallback
ConfigObject 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
andConfig
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 writeobject.withFallback(nonObject).withFallback(otherObject)
, thenotherObject
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 offoo
would be simply 10. Again, for details see the spec.- Specified by:
withFallback
in interfaceConfigMergeable
- Specified by:
withFallback
in interfaceConfigValue
- 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)
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get
ConfigValue get(java.lang.Object key)
Gets aConfigValue
at the given key, or returns null if there is no value. The returnedConfigValue
may haveConfigValueType.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 interfacejava.util.Map<java.lang.String,ConfigValue>
- Parameters:
key
- key to look up- Returns:
- the value at the key or null if none
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withOnlyKey
ConfigObject 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
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withoutKey
ConfigObject 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
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withValue
ConfigObject withValue(java.lang.String key, ConfigValue value)
Returns aConfigObject
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, usewithoutKey(String)
.- Parameters:
key
- key to addvalue
- value at the new key- Returns:
- the new instance with the new map entry
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withOrigin
ConfigObject withOrigin(ConfigOrigin origin)
Description copied from interface:ConfigValue
Returns aConfigValue
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 interfaceConfigValue
- Parameters:
origin
- the origin set on the returned value- Returns:
- the new ConfigValue with the given origin
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