Config
An immutable map from config paths to config values. Paths are dot-separated
expressions such as foo.bar.baz
. Values are as in JSON
(booleans, strings, numbers, lists, or objects), represented by
[[ConfigValue]]
instances. Values accessed through the
Config
interface are never null.
An immutable map from config paths to config values. Paths are dot-separated
expressions such as foo.bar.baz
. Values are as in JSON
(booleans, strings, numbers, lists, or objects), represented by
[[ConfigValue]]
instances. Values accessed through the
Config
interface are never null.
Config
is an immutable object and thus safe to use from multiple
threads. There's never a need for "defensive copies."
Fundamental operations on a Config
include getting configuration
values, resolving substitutions with resolve(), and
merging configs using
withFallback(ConfigMergeable).
All operations return a new immutable Config
rather than modifying
the original instance.
Examples
You can find an example app and library
on GitHub.
Also be sure to read the package-summary.html#package_description
package overview]]
which describes the big picture as shown in those examples.
Paths, keys, and Config vs. ConfigObject
Config
is a view onto a tree of [[ConfigObject]]
; the
corresponding object tree can be found through [[Config#root]]
.
ConfigObject
is a map from config keys, rather than
paths, to config values. Think of ConfigObject
as a JSON object
and Config
as a configuration API.
The API tries to consistently use the terms "key" and "path." A key is a key in a JSON object; it's just a string that's the key in a map. A "path" is a parseable expression with a syntax and it refers to a series of keys. Path expressions are described in the spec for Human-Optimized Config Object Notation. In brief, a path is period-separated so "a.b.c" looks for key c in object b in object a in the root object. Sometimes double quotes are needed around special characters in path expressions.
The API for a Config
is in terms of path expressions, while the API
for a ConfigObject
is in terms of keys. Conceptually, Config
is a one-level map from paths to values, while a
ConfigObject
is a tree of nested maps from keys to values.
Use ConfigUtil.joinPath(String*) and ConfigUtil.splitPath(String) to convert between path expressions and individual path elements (keys).
Another difference between Config
and ConfigObject
is that
conceptually, ConfigValue
s with a [[ConfigValue#valueType valueType]]
of [[ConfigValueType#NULL NULL]]
exist in a
ConfigObject
, while a Config
treats null values as if they
were missing. (With the exception of two methods: [[Config#hasPathOrNull]]
and [[Config#getIsNull]]
let you detect null
values.)
Getting configuration values
The "getters" on a Config
all work in the same way. They never return
null, nor do they return a ConfigValue
with
[[ConfigValue#valueType valueType]]
of [[ConfigValueType#NULL NULL]]
. Instead, they throw [[ConfigException.Missing]]
if the value is
completely absent or set to null. If the value is set to null, a subtype of
ConfigException.Missing
called [[ConfigException.Null]]
will be
thrown. [[ConfigException.WrongType]]
will be thrown anytime you ask for
a type and the value has an incompatible type. Reasonable type conversions
are performed for you though.
Iteration
If you want to iterate over the contents of a Config
, you can get its
ConfigObject
with [[#root]]
, and then iterate over the
ConfigObject
(which implements java.util.Map
). Or, you
can use [[#entrySet]]
which recurses the object tree for you and builds
up a Set
of all path-value pairs where the value is not null.
'''Resolving substitutions'''
''Substitutions'' are the ${foo.bar}
syntax in config
files, described in the <a href=
"https://github.com/lightbend/config/blob/master/HOCON.md#substitutions"
specification. Resolving substitutions replaces these references with real values.
Before using a Config
it's necessary to call resolve()
to handle substitutions (though ConfigFactory.load() and similar
methods will do the resolve for you already).
Merging
The full Config
for your application can be constructed using
the associative operation
withFallback(ConfigMergeable).
If you use ConfigFactory.load() (recommended), it
merges system properties over the top of application.conf
over
the top of reference.conf
, using withFallback
. You
can add in additional sources of configuration in the same way (usually,
custom layers should go either just above or just below
application.conf
, keeping reference.conf
at the
bottom and system properties at the top).
Serialization
Convert a Config
to a JSON or HOCON string by calling
root to get the ConfigObject and then call
render
on the root object, myConfig.root.render
. There's also a variant
render(ConfigRenderOptions)
inherited from ConfigValue which allows you to control
the format of the rendered string. (See [[ConfigRenderOptions]]
.) Note
that Config
does not remember the formatting of the original
file, so if you load, modify, and re-save a config file, it will be
substantially reformatted.
As an alternative to render, the
toString
method produces a debug-output-oriented
representation (which is not valid JSON).
Java serialization is supported as well for Config
and all
subtypes of ConfigValue
.
This is an interface but don't implement it yourself
Do not implement Config
; 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.
Value members
Abstract methods
Places the config inside a Config
at the given key. See also
atPath. Note that a key is NOT a path expression (see
ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
Places the config inside a Config
at the given key. See also
atPath. Note that a key is NOT a path expression (see
ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- key
key to store this config at.
- Returns
a
Config
instance containing this config at the given key.
Places the config inside another Config
at the given path.
Places the config inside another Config
at the given path.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
path expression to store this config at.
- Returns
a { @code Config} instance containing this config at the given path.
Validates this config against a reference config, throwing an exception if it is invalid. The purpose of this method is to "fail early" with a comprehensive list of problems; in general, anything this method can find would be detected later when trying to use the config, but it's often more user-friendly to fail right away when loading the config.
Validates this config against a reference config, throwing an exception if it is invalid. The purpose of this method is to "fail early" with a comprehensive list of problems; in general, anything this method can find would be detected later when trying to use the config, but it's often more user-friendly to fail right away when loading the config.
Using this method is always optional, since you can "fail late" instead.
You must restrict validation to paths you "own" (those whose meaning are defined by your code module). If you validate globally, you may trigger errors about paths that happen to be in the config but have nothing to do with your module. It's best to allow the modules owning those paths to validate them. Also, if every module validates only its own stuff, there isn't as much redundant work being done.
If no paths are specified in checkValid
's parameter list,
validation is for the entire config.
If you specify paths that are not in the reference config, those paths are ignored. (There's nothing to validate.)
Here's what validation involves:
-
All paths found in the reference config must be present in this config or an exception will be thrown.
Some changes in type from the reference config to this config will cause an exception to be thrown. Not all potential type problems are detected, in particular it's assumed that strings are compatible with everything except objects and lists. This is because string types are often "really" some other type (system properties always start out as strings, or a string like "5ms" could be used with getDuration(String)). Also, it's allowed to set any type to null or override null with any type.
Any unresolved substitutions in this config will cause a validation failure; both the reference config and this config should be resolved before validation. If the reference config is unresolved, it's a bug in the caller of this method.
If you want to allow a certain setting to have a flexible type (or otherwise want validation to be looser for some settings), you could either remove the problematic setting from the reference config provided to this method, or you could intercept the validation exception and screen out certain problems. Of course, this will only work if all other callers of this method are careful to restrict validation to their own paths, as they should be.
If validation fails, the thrown exception contains a list of all problems
found. See [[ConfigException.ValidationFailed#problems]]
. The
exception's getMessage
will have all the problems
concatenated into one huge string, as well.
Again, checkValid
can't guess every domain-specific way a
setting can be invalid, so some problems may arise later when attempting
to use the config. checkValid
is limited to reporting
generic, but common, problems such as missing settings and blatant type
incompatibilities.
- Value Params
- reference
a reference configuration
- restrictToPaths
only validate values underneath these paths that your code module owns and understands
- Throws
- ConfigException.BugOrBroken
if the reference config is unresolved or caller otherwise misuses the API
- ConfigException.NotResolved
if this config is not resolved
- ConfigException.ValidationFailed
if there are any validation issues
Returns the set of path-value pairs, excluding any null values, found by
recursing [[#root the root object]]
. Note that this is very
different from root.entrySet
which returns the set of
immediate-child keys in the root object and includes null values.
Returns the set of path-value pairs, excluding any null values, found by
recursing [[#root the root object]]
. Note that this is very
different from root.entrySet
which returns the set of
immediate-child keys in the root object and includes null values.
Entries contain path expressions meaning there may be quoting
and escaping involved. Parse path expressions with
[[ConfigUtil#splitPath]]
.
Because a Config
is conceptually a single-level map from
paths to values, there will not be any [[ConfigObject]]
values in the
entries (that is, all entries represent leaf nodes). Use
[[ConfigObject]]
rather than Config
if you want a tree.
(OK, this is a slight lie: Config
entries may contain
[[ConfigList]]
and the lists may contain objects. But no objects are
directly included as entry values.)
- Returns
set of paths with non-null values, built up by recursing the entire tree of { @link ConfigObject} and creating an entry for each leaf value.
Gets the value at the path as an unwrapped Java boxed value (
java.lang.Boolean
java.lang.Integer
, and
so on - see [[ConfigValue#unwrapped]]
).
Gets the value at the path as an unwrapped Java boxed value (
java.lang.Boolean
java.lang.Integer
, and
so on - see [[ConfigValue#unwrapped]]
).
- Value Params
- path
path expression
- Returns
the unwrapped value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
Gets a list value with any kind of elements. Throws if the
path is unset or null or not a list. Each element is
"unwrapped" (see [[ConfigValue#unwrapped]]
).
Gets a list value with any kind of elements. Throws if the
path is unset or null or not a list. Each element is
"unwrapped" (see [[ConfigValue#unwrapped]]
).
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list
- Value Params
- path
path expression
- Returns
the boolean value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to boolean
Gets a list value with boolean elements. Throws if the path is unset or null or not a list or contains values not convertible to boolean.
Gets a list value with boolean elements. Throws if the path is unset or null or not a list or contains values not convertible to boolean.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of booleans
Gets a value as a size in bytes (parses special strings like "128M"). If the value is already a number, then it's left alone; if it's a string, it's parsed understanding unit suffixes such as "128K", as documented in the the spec.
Gets a value as a size in bytes (parses special strings like "128M"). If the value is already a number, then it's left alone; if it's a string, it's parsed understanding unit suffixes such as "128K", as documented in the the spec.
- Value Params
- path
path expression
- Returns
the value at the requested path, in bytes
- Throws
- ConfigException.BadValue
if value cannot be parsed as a size in bytes
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
Gets a list value with elements representing a size in bytes. Throws if the path is unset or null or not a list or contains values not convertible to memory sizes.
Gets a list value with elements representing a size in bytes. Throws if the path is unset or null or not a list or contains values not convertible to memory sizes.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of memory sizes
- Value Params
- path
path expression
- Returns
the nested
Config
value at the requested path- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a Config
Gets a list value with Config
elements.
Throws if the path is unset or null or not a list or
contains values not convertible to Config
.
Gets a list value with Config
elements.
Throws if the path is unset or null or not a list or
contains values not convertible to Config
.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of configs
- Value Params
- path
path expression
- Returns
the floating-point value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a double
Gets a list value with double elements. Throws if the path is unset or null or not a list or contains values not convertible to double.
Gets a list value with double elements. Throws if the path is unset or null or not a list or contains values not convertible to double.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of doubles
Gets a value as a duration in a specified
java.util.concurrent.TimeUnit
. If the value is already a
number, then it's taken as milliseconds and then converted to the
requested TimeUnit; if it's a string, it's parsed understanding units
suffixes like "10m" or "5ns" as documented in the <a
the HOCON spec.
Gets a value as a duration in a specified
java.util.concurrent.TimeUnit
. If the value is already a
number, then it's taken as milliseconds and then converted to the
requested TimeUnit; if it's a string, it's parsed understanding units
suffixes like "10m" or "5ns" as documented in the <a
the HOCON spec.
- Value Params
- path
path expression
- unit
convert the return value to this time unit
- Returns
the duration value at the requested path, in the given TimeUnit
- Throws
- ConfigException.BadValue
if value cannot be parsed as a number of the given TimeUnit
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
- Since
1.2.0
Gets a value as a java.time.Duration. If the value is already a number, then it's taken as milliseconds; if it's a string, it's parsed understanding units suffixes like "10m" or "5ns" as documented in the the spec. This method never returns null.
Gets a value as a java.time.Duration. If the value is already a number, then it's taken as milliseconds; if it's a string, it's parsed understanding units suffixes like "10m" or "5ns" as documented in the the spec. This method never returns null.
- Value Params
- path
path expression
- Returns
the duration value at the requested path
- Throws
- ConfigException.BadValue
if value cannot be parsed as a number of the given TimeUnit
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
- Since
1.3.0
Gets a list, converting each value in the list to a duration, using the same rules as getDuration(String, TimeUnit).
Gets a list, converting each value in the list to a duration, using the same rules as getDuration(String, TimeUnit).
- Value Params
- path
a path expression
- unit
time units of the returned values
- Returns
list of durations, in the requested units
- Since
1.2.0
Gets a list, converting each value in the list to a duration, using the same rules as getDuration(String).
Gets a list, converting each value in the list to a duration, using the same rules as getDuration(String).
- Value Params
- path
a path expression
- Returns
list of durations
- Since
1.3.0
Gets the integer at the given path. If the value at the path has a fractional (floating point) component, it will be discarded and only the integer part will be returned (it works like a "narrowing primitive conversion" in the Java language specification).
Gets the integer at the given path. If the value at the path has a fractional (floating point) component, it will be discarded and only the integer part will be returned (it works like a "narrowing primitive conversion" in the Java language specification).
- Value Params
- path
path expression
- Returns
the 32-bit integer value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to an int (for example it is out of range, or it's a boolean value)
Gets a list value with int elements. Throws if the path is unset or null or not a list or contains values not convertible to int.
Gets a list value with int elements. Throws if the path is unset or null or not a list or contains values not convertible to int.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of ints
Checks whether a value is set to null at the given path,
but throws an exception if the value is entirely
unset. This method will not throw if [[#hasPathOrNull]]
returned true for the same path, so to avoid any possible exception check
hasPathOrNull
first. However, an exception
for unset paths will usually be the right thing (because a
reference.conf
should exist that has the path
set, the path should never be unset unless something is
broken).
Checks whether a value is set to null at the given path,
but throws an exception if the value is entirely
unset. This method will not throw if [[#hasPathOrNull]]
returned true for the same path, so to avoid any possible exception check
hasPathOrNull
first. However, an exception
for unset paths will usually be the right thing (because a
reference.conf
should exist that has the path
set, the path should never be unset unless something is
broken).
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
the path expression
- Returns
true if the value exists and is null, false if it exists and is not null
- Throws
- ConfigException.BadPath
if the path expression is invalid
- ConfigException.Missing
if value is not set at all
Gets a list value (with any element type) as a [[ConfigList]]
, which
implements java.util.List
. Throws if the path is
unset or null.
Gets a list value (with any element type) as a [[ConfigList]]
, which
implements java.util.List
. Throws if the path is
unset or null.
- Value Params
- path
the path to the list value.
- Returns
the { @link ConfigList} at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a ConfigList
Gets the long integer at the given path. If the value at the path has a fractional (floating point) component, it will be discarded and only the integer part will be returned (it works like a "narrowing primitive conversion" in the Java language specification).
Gets the long integer at the given path. If the value at the path has a fractional (floating point) component, it will be discarded and only the integer part will be returned (it works like a "narrowing primitive conversion" in the Java language specification).
- Value Params
- path
path expression
- Returns
the 64-bit long value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a long
Gets a list value with long elements. Throws if the path is unset or null or not a list or contains values not convertible to long.
Gets a list value with long elements. Throws if the path is unset or null or not a list or contains values not convertible to long.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of longs
Gets a value as an amount of memory (parses special strings like "128M"). If the value is already a number, then it's left alone; if it's a string, it's parsed understanding unit suffixes such as "128K", as documented in the the spec.
Gets a value as an amount of memory (parses special strings like "128M"). If the value is already a number, then it's left alone; if it's a string, it's parsed understanding unit suffixes such as "128K", as documented in the the spec.
- Value Params
- path
path expression
- Returns
the value at the requested path, in bytes
- Throws
- ConfigException.BadValue
if value cannot be parsed as a size in bytes
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
- Since
1.3.0
Gets a list, converting each value in the list to a memory size, using the
same rules as [[#getMemorySize]]
.
Gets a list, converting each value in the list to a memory size, using the
same rules as [[#getMemorySize]]
.
- Value Params
- path
a path expression
- Returns
list of memory sizes
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of memory sizes
- Since
1.3.0
- Value Params
- path
path expression
- Returns
the numeric value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a number
Gets a list value with number elements. Throws if the path is unset or null or not a list or contains values not convertible to number.
Gets a list value with number elements. Throws if the path is unset or null or not a list or contains values not convertible to number.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of numbers
- Value Params
- path
path expression
- Returns
the { @link ConfigObject} value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to an object
Gets a list value with object elements. Throws if the
path is unset or null or not a list or contains values not
convertible to ConfigObject
.
Gets a list value with object elements. Throws if the
path is unset or null or not a list or contains values not
convertible to ConfigObject
.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of objects
Gets a value as a java.time.Period. If the value is already a number, then it's taken as days; if it's a string, it's parsed understanding units suffixes like "10d" or "5w" as documented in the the spec. This method never returns null.
Gets a value as a java.time.Period. If the value is already a number, then it's taken as days; if it's a string, it's parsed understanding units suffixes like "10d" or "5w" as documented in the the spec. This method never returns null.
- Value Params
- path
path expression
- Returns
the period value at the requested path
- Throws
- ConfigException.BadValue
if value cannot be parsed as a number of the given TimeUnit
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
- Since
1.3.0
- Value Params
- path
path expression
- Returns
the string value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a string
Gets a list value with string elements. Throws if the path is unset or null or not a list or contains values not convertible to string.
Gets a list value with string elements. Throws if the path is unset or null or not a list or contains values not convertible to string.
- Value Params
- path
the path to the list value.
- Returns
the list at the path
- Throws
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to a list of strings
Gets a value as a java.time.temporal.TemporalAmount. This method will first try get get the value as a java.time.Duration, and if unsuccessful, then as a java.time.Period. This means that values like "5m" will be parsed as 5 minutes rather than 5 months
Gets a value as a java.time.temporal.TemporalAmount. This method will first try get get the value as a java.time.Duration, and if unsuccessful, then as a java.time.Period. This means that values like "5m" will be parsed as 5 minutes rather than 5 months
- Value Params
- path
path expression
- Returns
the temporal value at the requested path
- Throws
- ConfigException.BadValue
if value cannot be parsed as a TemporalAmount
- ConfigException.Missing
if value is absent or null
- ConfigException.WrongType
if value is not convertible to Long or String
Gets the value at the given path, unless the value is a
null value or missing, in which case it throws just like
the other getters. Use get
on the [[Config#root]]
object (or other object in the tree) if you
want an unprocessed value.
Gets the value at the given path, unless the value is a
null value or missing, in which case it throws just like
the other getters. Use get
on the [[Config#root]]
object (or other object in the tree) if you
want an unprocessed value.
- Value Params
- path
path expression
- Returns
the value at the requested path
- Throws
- ConfigException.Missing
if value is absent or null
Checks whether a value is present and non-null at the given path. This
differs in two ways from Map.containsKey
as implemented by
[[ConfigObject]]
: it looks for a path expression, not a key; and it
returns false for null values, while containsKey
returns true
indicating that the object contains a null value for the key.
Checks whether a value is present and non-null at the given path. This
differs in two ways from Map.containsKey
as implemented by
[[ConfigObject]]
: it looks for a path expression, not a key; and it
returns false for null values, while containsKey
returns true
indicating that the object contains a null value for the key.
If a path exists according to [[#hasPath]]
, then
[[#getValue]]
will never throw an exception. However, the
typed getters, such as [[#getInt]]
, will still throw if the
value is not convertible to the requested type.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
the path expression
- Returns
true if a non-null value is present at the path
- Throws
- ConfigException.BadPath
if the path expression is invalid
Checks whether a value is present at the given path, even
if the value is null. Most of the getters on
Config
will throw if you try to get a null
value, so if you plan to call [[#getValue]]
,
[[#getInt]]
, or another getter you may want to
use plain [[#hasPath]]
rather than this method.
Checks whether a value is present at the given path, even
if the value is null. Most of the getters on
Config
will throw if you try to get a null
value, so if you plan to call [[#getValue]]
,
[[#getInt]]
, or another getter you may want to
use plain [[#hasPath]]
rather than this method.
To handle all three cases (unset, null, and a non-null value) the code might look like:
if (config.hasPathOrNull(path)) {
if (config.getIsNull(path)) {
// handle null setting
} else {
// get and use non-null setting
}
} else {
// handle entirely unset path
}
However, the usual thing is to allow entirely unset
paths to be a bug that throws an exception (because you set
a default in your reference.conf
), so in that
case it's OK to call [[#getIsNull]]
without
checking hasPathOrNull
first.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
the path expression
- Returns
true if a value is present at the path, even if the value is null
- Throws
- ConfigException.BadPath
if the path expression is invalid
Returns true if the Config
's root object contains no key-value
pairs.
Returns true if the Config
's root object contains no key-value
pairs.
- Returns
true if the configuration is empty
Checks whether the config is completely resolved. After a successful call
to resolve() it will be completely resolved, but after calling
resolve(ConfigResolveOptions)
with allowUnresolved
set in the options, it may or may not be
completely resolved. A newly-loaded config may or may not be completely
resolved depending on whether there were substitutions present in the
file.
Checks whether the config is completely resolved. After a successful call
to resolve() it will be completely resolved, but after calling
resolve(ConfigResolveOptions)
with allowUnresolved
set in the options, it may or may not be
completely resolved. A newly-loaded config may or may not be completely
resolved depending on whether there were substitutions present in the
file.
- Returns
true if there are no unresolved substitutions remaining in this configuration.
- Since
1.2.0
Gets the origin of the Config
, which may be a file, or a file
with a line number, or just a descriptive phrase.
Gets the origin of the Config
, which may be a file, or a file
with a line number, or just a descriptive phrase.
- Returns
the origin of the
Config
for use in error messages
Returns a replacement config with all substitutions (the
${foo.bar}
syntax, see
HOCON spec
for resolved. Substitutions are looked up using this
Config
as the root object, that is, a substitution
${foo.bar}
will be replaced with the result of
getValue("foo.bar")
.
Returns a replacement config with all substitutions (the
${foo.bar}
syntax, see
HOCON spec
for resolved. Substitutions are looked up using this
Config
as the root object, that is, a substitution
${foo.bar}
will be replaced with the result of
getValue("foo.bar")
.
This method uses [[ConfigResolveOptions#defaults]]
, there is
another variant
resolve(ConfigResolveOptions)
which lets you specify non-default options.
A given [[Config]]
must be resolved before using it to retrieve
config values, but ideally should be resolved one time for your entire
stack of fallbacks (see [[Config#withFallback]]
). Otherwise, some
substitutions that could have resolved with all fallbacks available may
not resolve, which will be potentially confusing for your application's
users.
resolve
should be invoked on root config objects, rather
than on a subtree (a subtree is the result of something like
config.getConfig("foo")
). The problem with
resolve
on a subtree is that substitutions are relative to
the root of the config and the subtree will have no way to get values
from the root. For example, if you did
config.getConfig("foo").resolve
on the below config file,
it would not work:
common-value = 10
foo {
whatever = ${common-value}
}
Many methods on [[ConfigFactory]]
such as
ConfigFactory.load() automatically resolve the
loaded Config
on the loaded stack of config files.
Resolving an already-resolved config is a harmless no-op, but again, it is best to resolve an entire stack of fallbacks (such as all your config files combined) rather than resolving each one individually.
- Returns
an immutable object with substitutions resolved
- Throws
- ConfigException
some other config exception if there are other problems
- ConfigException.UnresolvedSubstitution
if any substitutions refer to nonexistent paths
Like resolve() except that substitution values are looked
up in the given source, rather than in this instance. This is a
special-purpose method which doesn't make sense to use in most cases;
it's only needed if you're constructing some sort of app-specific custom
approach to configuration. The more usual approach if you have a source
of substitution values would be to merge that source into your config
stack using [[Config#withFallback]]
and then resolve.
Like resolve() except that substitution values are looked
up in the given source, rather than in this instance. This is a
special-purpose method which doesn't make sense to use in most cases;
it's only needed if you're constructing some sort of app-specific custom
approach to configuration. The more usual approach if you have a source
of substitution values would be to merge that source into your config
stack using [[Config#withFallback]]
and then resolve.
Note that this method does NOT look in this instance for substitution
values. If you want to do that, you could either merge this instance into
your value source using [[Config#withFallback]]
, or you could resolve
multiple times with multiple sources (using
[[ConfigResolveOptions#setAllowUnresolved]]
so the partial
resolves don't fail).
- Value Params
- source
configuration to pull values from
- Returns
an immutable object with substitutions resolved
- Throws
- ConfigException
some other config exception if there are other problems
- ConfigException.UnresolvedSubstitution
if any substitutions refer to paths which are not in the source
- Since
1.2.0
Like resolveWith(Config) but allows you to specify non-default options.
Like resolveWith(Config) but allows you to specify non-default options.
- Value Params
- options
resolve options
- source
source configuration to pull values from
- Returns
the resolved
Config
(may be only partially resolved if options are set to allow unresolved)- Since
1.2.0
Gets the Config
as a tree of [[ConfigObject]]
. This is a
constant-time operation (it is not proportional to the number of values
in the Config
).
Gets the Config
as a tree of [[ConfigObject]]
. This is a
constant-time operation (it is not proportional to the number of values
in the Config
).
- Returns
the root object in the configuration
Clone the config with only the given path (and its children) retained; all sibling paths are removed.
Clone the config with only the given path (and its children) retained; all sibling paths are removed.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
path to keep
- Returns
a copy of the config minus all paths except the one specified
Returns a Config
based on this one, but with the given path set
to the given value. Does not modify this instance (since it's immutable).
If the path already has a value, that value is replaced. To remove a
value, use withoutPath.
Returns a Config
based on this one, but with the given path set
to the given value. Does not modify this instance (since it's immutable).
If the path already has a value, that value is replaced. To remove a
value, use withoutPath.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
path expression for the value's new location
- value
value at the new path
- Returns
the new instance with the new map entry
Clone the config with the given path removed.
Clone the config with the given path removed.
Note that path expressions have a syntax and sometimes require quoting
(see ConfigUtil$.joinPath and [[ConfigUtil#splitPath]]
).
- Value Params
- path
path expression to remove
- Returns
a copy of the config minus the specified path