abstract class CommandLinePropertySource<T : Any> : EnumerablePropertySource<T>
Abstract base class for PropertySource implementations backed by command line arguments. The parameterized type With the bootstrap logic above, the AppConfig class may @Inject the Spring Environment and query it directly for properties: Because the CommandLinePropertySource was added to the Environment 's set of MutablePropertySources using the #addFirst method, it has highest search precedence, meaning that while "db.hostname" and other properties may exist in other property sources such as the system environment variables, it will be chosen from the command line property source first. This is a reasonable approach given that arguments specified on the command line are naturally more specific than those specified as environment variables.
As an alternative to injecting the Working with option arguments
Individual command line arguments are represented as properties through the usual 'o1' and 'o2' are treated as "option arguments", and the following assertions would evaluate true: Note that the 'o2' option has no argument, but getProperty("o2") resolves to empty string ("" ) as opposed to null , while getProperty("o3") resolves to null because it was not specified. This behavior is consistent with the general contract to be followed by all PropertySource implementations.
Note also that while "--" was used in the examples above to denote an option argument, this syntax may vary across individual command line argument libraries. For example, a JOpt- or Commons CLI-based implementation may allow for single dash ("-") "short" option arguments, etc. Working with non-option argumentsNon-option arguments are also supported through this abstraction. Any arguments supplied without an option-style prefix such as "-" or "--" are considered "non-option arguments" and available through the special property. If multiple non-option arguments are specified, the value of this property will be a comma-delimited string containing all of the arguments. This approach ensures a simple and consistent return type (String) for all properties from a In this example, "o1" and "o2" would be considered "option arguments", while the two filesystem paths qualify as "non-option arguments". As such, the following assertions will evaluate true:
As mentioned above, when used in conjunction with the Spring
The name of the special "non-option arguments" property may be customized through the Limitations This abstraction is not intended to expose the full power of underlying command line parsing APIs such as JOpt or Commons CLI. It's intent is rather just the opposite: to provide the simplest possible abstraction for accessing command line arguments after they have been parsed. So the typical case will involve fully configuring the underlying command line parsing API, parsing the String[] of arguments coming into the main method, and then simply providing the parsing results to an implementation of CommandLinePropertySource . At that point, all arguments can be considered either 'option' or 'non-option' arguments and as described above can be accessed through the normal PropertySource and Environment APIs.
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open class CompositePropertySource : EnumerablePropertySource<Any>
Composite PropertySource implementation that iterates over a set of PropertySource instances. Necessary in cases where multiple property sources share the same name, e.g. when multiple values are supplied to As of Spring 4.1.2, this class extends EnumerablePropertySource instead of plain PropertySource, exposing |
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open class JOptCommandLinePropertySource : CommandLinePropertySource<OptionSet>
CommandLinePropertySource implementation backed by a JOpt OptionSet. Typical usage Configure and execute an See CommandLinePropertySource for complete general usage examples.
Requires JOpt Simple version 4.3 or higher. Tested against JOpt up until 5.0. |
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open class PropertySourcesPropertyResolver : AbstractPropertyResolver
PropertyResolver implementation that resolves property values against an underlying set of PropertySources. |
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open class SimpleCommandLinePropertySource : CommandLinePropertySource<CommandLineArgs>
CommandLinePropertySource implementation backed by a simple String array. Purpose This That is, options must be prefixed with "-- ", and may or may not specify a value. If a value is specified, the name and value must be separated without spaces by an equals sign ("="). Valid examples of option arguments Invalid examples of option arguments Working with non-option arguments Any and all arguments specified at the command line without the "-- " option prefix will be considered as "non-option arguments" and made available through the #getNonOptionArgs() method. Typical usage See CommandLinePropertySource for complete general usage examples. Beyond the basics
When more fully-featured command line parsing is necessary, consider using the provided JOptCommandLinePropertySource, or implement your own |
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open class SystemEnvironmentPropertySource : MapPropertySource
Specialization of MapPropertySource designed for use with system environment variables. Compensates for constraints in Bash and other shells that do not allow for variables containing the period character and/or hyphen character; also allows for uppercase variations on property names for more idiomatic shell use. For example, a call to
The same applies for calls to This feature is particularly useful when specifying active or default profiles as environment variables. The following is not allowable under Bash: However, the following syntax is permitted and is also more conventional:
Enable debug- or trace-level logging for this class (or package) for messages explaining when these 'property name resolutions' occur. This property source is included by default in StandardEnvironment and all its subclasses. |
open class MissingRequiredPropertiesException : IllegalStateException
Exception thrown when required properties are not found. |
operator fun PropertyResolver.get(key: String): String
Extension for PropertyResolver.getRequiredProperty providing Array like getter. |