Config

All Superinterfaces:

ConfigMergeable
```
public interface Config
extends ConfigMergeable
```
An immutable map from config paths to config values.
Contrast with ConfigObject which is a map from config keys, rather than paths, to config values. A Config contains a tree of ConfigObject, and root() returns the tree's root object.
Throughout the API, there is a distinction between "keys" and "paths". 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(java.lang.String...) and ConfigUtil.splitPath(java.lang.String) to convert between path expressions and individual path elements (keys).
Another difference between Config and ConfigObject is that conceptually, ConfigValues with a valueType() of NULL exist in a ConfigObject, while a Config treats null values as if they were missing.
Config is an immutable object and thus safe to use from multiple threads. There's never a need for "defensive copies."
The "getters" on a Config all work in the same way. They never return null, nor do they return a ConfigValue with valueType() of 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.
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.
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.

Method Summary

Methods
Modifier and Type	Method and Description
`Config`	`atKey(String key)` Places the config inside a `Config` at the given key.
`Config`	`atPath(String path)` Places the config inside another `Config` at the given path.
`void`	`checkValid(Config reference, String... restrictToPaths)` Validates this config against a reference config, throwing an exception if it is invalid.
`Set<Map.Entry<String,ConfigValue>>`	`entrySet()` Returns the set of path-value pairs, excluding any null values, found by recursing `the root object`.
`Object`	`getAnyRef(String path)` Gets the value at the path as an unwrapped Java boxed value ( `Boolean`, `Integer`, and so on - see `ConfigValue.unwrapped()`).
`List<? extends Object>`	`getAnyRefList(String path)`
`boolean`	`getBoolean(String path)`
`List<Boolean>`	`getBooleanList(String path)`
`Long`	`getBytes(String path)` Gets a value as a size in bytes (parses special strings like "128M").
`List<Long>`	`getBytesList(String path)`
`Config`	`getConfig(String path)`
`List<? extends Config>`	`getConfigList(String path)`
`double`	`getDouble(String path)`
`List<Double>`	`getDoubleList(String path)`
`int`	`getInt(String path)`
`List<Integer>`	`getIntList(String path)`
`ConfigList`	`getList(String path)` Gets a list value (with any element type) as a `ConfigList`, which implements `java.util.List<ConfigValue>`.
`long`	`getLong(String path)`
`List<Long>`	`getLongList(String path)`
`Long`	`getMilliseconds(String path)` Get value as a duration in milliseconds.
`List<Long>`	`getMillisecondsList(String path)`
`Long`	`getNanoseconds(String path)` Get value as a duration in nanoseconds.
`List<Long>`	`getNanosecondsList(String path)`
`Number`	`getNumber(String path)`
`List<Number>`	`getNumberList(String path)`
`ConfigObject`	`getObject(String path)`
`List<? extends ConfigObject>`	`getObjectList(String path)`
`String`	`getString(String path)`
`List<String>`	`getStringList(String path)`
`ConfigValue`	`getValue(String path)` 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.
`boolean`	`hasPath(String path)` Checks whether a value is present and non-null at the given path.
`boolean`	`isEmpty()` Returns true if the `Config`'s root object contains no key-value pairs.
`ConfigOrigin`	`origin()` Gets the origin of the `Config`, which may be a file, or a file with a line number, or just a descriptive phrase.
`Config`	`resolve()` Returns a replacement config with all substitutions (the `${foo.bar}` syntax, see the spec) resolved.
`Config`	`resolve(ConfigResolveOptions options)` Like `resolve()` but allows you to specify non-default options.
`ConfigObject`	`root()` Gets the `Config` as a tree of `ConfigObject`.
`Config`	`withFallback(ConfigMergeable other)` Returns a new value computed by merging this value with another, with keys in this value "winning" over the other one.
`Config`	`withOnlyPath(String path)` Clone the config with only the given path (and its children) retained; all sibling paths are removed.
`Config`	`withoutPath(String path)` Clone the config with the given path removed.
`Config`	`withValue(String path, ConfigValue value)` Returns a `Config` based on this one, but with the given path set to the given value.

- Method Detail
  - root
```
ConfigObject root()
```
    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
  - origin
```
ConfigOrigin origin()
```
    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
  - withFallback
```
Config 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. 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.
    The semantics of merging are described in the spec for HOCON.
    Note 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. Both non-objects, and any object which has fallen back to a non-object, block subsequent fallbacks.
    
    Specified by:
    
    withFallback in interface ConfigMergeable
    
    Parameters:
    other - an object whose keys should be used if the keys are not present in this one
    
    Returns:
    a new object (or the original one, if the fallback doesn't get used)
  - resolve
```
Config resolve()
```
    Returns a replacement config with all substitutions (the ${foo.bar} syntax, see the spec) 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 withFallback(com.typesafe.config.ConfigMergeable)). Otherwise, some substitutions that could have resolved with all fallbacks available may not resolve, which will be a user-visible oddity.
    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}
   }
 
```
    Returns:
    an immutable object with substitutions resolved
    
    Throws:
    
    ConfigException.UnresolvedSubstitution - if any substitutions refer to nonexistent paths
    
    ConfigException - some other config exception if there are other problems
  - resolve
```
Config resolve(ConfigResolveOptions options)
```
    Like resolve() but allows you to specify non-default options.
    
    Parameters:
    options - resolve options
    
    Returns:
    the resolved Config
  - checkValid
```
void checkValid(Config reference,
              String... restrictToPaths)
```
    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 getMilliseconds(java.lang.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.
    Parameters:
    reference - a reference configuration
    restrictToPaths - only validate values underneath these paths that your code module owns and understands
    
    Throws:
    
    ConfigException.ValidationFailed - if there are any validation issues
    
    ConfigException.NotResolved - if this config is not resolved
    
    ConfigException.BugOrBroken - if the reference config is unresolved or caller otherwise misuses the API
  - hasPath
```
boolean hasPath(String path)
```
    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(String), then getValue(String) will never throw an exception. However, the typed getters, such as getInt(String), will still throw if the value is not convertible to the requested type.
    
    Parameters:
    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
  - isEmpty
```
boolean isEmpty()
```
    Returns true if the Config's root object contains no key-value pairs.
    
    Returns:
    true if the configuration is empty
  - entrySet
```
Set<Map.Entry<String,ConfigValue>> entrySet()
```
    Returns the set of path-value pairs, excluding any null values, found by recursing 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:
    set of paths with non-null values, built up by recursing the entire tree of ConfigObject
  - getBoolean
```
boolean getBoolean(String path)
```
    Parameters:
    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
  - getNumber
```
Number getNumber(String path)
```
    Parameters:
    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
  - getInt
```
int getInt(String path)
```
    Parameters:
    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)
  - getLong
```
long getLong(String path)
```
    Parameters:
    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
  - getDouble
```
double getDouble(String path)
```
    Parameters:
    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
  - getString
```
String getString(String path)
```
    Parameters:
    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
  - getObject
```
ConfigObject getObject(String path)
```
    Parameters:
    path - path expression
    
    Returns:
    the 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
  - getConfig
```
Config getConfig(String path)
```
    Parameters:
    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
  - getAnyRef
```
Object getAnyRef(String path)
```
    Gets the value at the path as an unwrapped Java boxed value ( Boolean, Integer, and so on - see ConfigValue.unwrapped()).
    
    Parameters:
    path - path expression
    
    Returns:
    the unwrapped value at the requested path
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
  - getValue
```
ConfigValue getValue(String path)
```
    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 root() object (or other object in the tree) if you want an unprocessed value.
    
    Parameters:
    path - path expression
    
    Returns:
    the value at the requested path
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
  - getBytes
```
Long getBytes(String path)
```
    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.
    
    Parameters:
    path - path expression
    
    Returns:
    the value at the requested path, in bytes
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
    
    ConfigException.WrongType - if value is not convertible to Long or String
    
    ConfigException.BadValue - if value cannot be parsed as a size in bytes
  - getMilliseconds
```
Long getMilliseconds(String path)
```
    Get value as a duration in milliseconds. If the value is already a number, then it's left alone; if it's a string, it's parsed understanding units suffixes like "10m" or "5ns" as documented in the the spec.
    
    Parameters:
    path - path expression
    
    Returns:
    the duration value at the requested path, in milliseconds
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
    
    ConfigException.WrongType - if value is not convertible to Long or String
    
    ConfigException.BadValue - if value cannot be parsed as a number of milliseconds
  - getNanoseconds
```
Long getNanoseconds(String path)
```
    Get value as a duration in nanoseconds. If the value is already a number it's taken as milliseconds and converted to nanoseconds. If it's a string, it's parsed understanding unit suffixes, as for getMilliseconds(String).
    
    Parameters:
    path - path expression
    
    Returns:
    the duration value at the requested path, in nanoseconds
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
    
    ConfigException.WrongType - if value is not convertible to Long or String
    
    ConfigException.BadValue - if value cannot be parsed as a number of nanoseconds
  - getList
```
ConfigList getList(String path)
```
    Gets a list value (with any element type) as a ConfigList, which implements java.util.List<ConfigValue>. Throws if the path is unset or null.
    
    Parameters:
    path - the path to the list value.
    
    Returns:
    the ConfigList at the path
    
    Throws:
    
    ConfigException.Missing - if value is absent or null
    
    ConfigException.WrongType - if value is not convertible to a ConfigList
  - getBooleanList
```
List<Boolean> getBooleanList(String path)
```
  - getNumberList
```
List<Number> getNumberList(String path)
```
  - getIntList
```
List<Integer> getIntList(String path)
```
  - getLongList
```
List<Long> getLongList(String path)
```
  - getDoubleList
```
List<Double> getDoubleList(String path)
```
  - getStringList
```
List<String> getStringList(String path)
```
  - getObjectList
```
List<? extends ConfigObject> getObjectList(String path)
```
  - getConfigList
```
List<? extends Config> getConfigList(String path)
```
  - getAnyRefList
```
List<? extends Object> getAnyRefList(String path)
```
  - getBytesList
```
List<Long> getBytesList(String path)
```
  - getMillisecondsList
```
List<Long> getMillisecondsList(String path)
```
  - getNanosecondsList
```
List<Long> getNanosecondsList(String path)
```
  - withOnlyPath
```
Config withOnlyPath(String path)
```
    Clone the config with only the given path (and its children) retained; all sibling paths are removed.
    
    Parameters:
    path - path to keep
    
    Returns:
    a copy of the config minus all paths except the one specified
  - withoutPath
```
Config withoutPath(String path)
```
    Clone the config with the given path removed.
    
    Parameters:
    path - path to remove
    
    Returns:
    a copy of the config minus the specified path
  - atPath
```
Config atPath(String path)
```
    Places the config inside another Config at the given path.
    
    Parameters:
    path - path to store this config at.
    
    Returns:
    a Config instance containing this config at the given path.
  - atKey
```
Config atKey(String key)
```
    Places the config inside a Config at the given key. See also atPath().
    
    Parameters:
    key - key to store this config at.
    
    Returns:
    a Config instance containing this config at the given key.
  - withValue
```
Config withValue(String path,
               ConfigValue value)
```
    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().
    
    Parameters:
    path - path to add
    value - value at the new path
    
    Returns:
    the new instance with the new map entry

Interface Config

Method Summary

Method Detail

root

origin

withFallback

resolve

resolve

checkValid

hasPath

isEmpty

entrySet

getBoolean

getNumber

getInt

getLong

getDouble

getString

getObject

getConfig

getAnyRef

getValue

getBytes

getMilliseconds

getNanoseconds

getList

getBooleanList

getNumberList

getIntList

getLongList

getDoubleList

getStringList

getObjectList

getConfigList

getAnyRefList

getBytesList

getMillisecondsList

getNanosecondsList

withOnlyPath

withoutPath

atPath

atKey

withValue