org.yarnandtail.andhow.load.std

Class StdMainStringArgsLoader

java.lang.Object

org.yarnandtail.andhow.load.BaseLoader

org.yarnandtail.andhow.load.KeyValuePairLoader

org.yarnandtail.andhow.load.std.StdMainStringArgsLoader

All Implemented Interfaces:

Loader, ReadLoader, StandardLoader

public class StdMainStringArgsLoader
extends KeyValuePairLoader
implements StandardLoader

Reads an array of Strings containing key value pairs in the form key=value, and loads the value for any key that matches a Property. This is normally used to read in command line arguments.

Position in Standard Loading Order, first to last

• StdFixedValueLoader
• StdMainStringArgsLoader <-- This loader
• StdSysPropLoader
• StdEnvVarLoader
• StdJndiLoader
• StdPropFileOnFilesystemLoader
• StdPropFileOnClasspathLoader

Property value loading is based on a 'first win' strategy, so the first loader to find a value for a property sets the value.

Typical Use Case

An executable jar or desktop application accepts command line arguments at startup to configure the application. This loader loads the String[] args passed to the main(String[] args), which Java passes from the command line. This is the most common usage, however, your application may retrieve an array of String's from anywhere to pass to AndHow at startup.

Basic Behaviors

• Pre-trims String values: Yes
• Complains about unrecognized properties: No
• Default behavior: None - This loader is only active if command line arguments are passed in as shown below

Loader Details and Configuration

AndHow is not 'there' to somehow intercept command line arguments - Your application code will need to do that and pass those arguments to AndHow, like this:

 import org.yarnandtail.andhow.*;
 
 public class MyAppClass {
   public static void main(String[] args) {
     AndHow.findConfig()
       .setCmdLineArgs(args)
       .build();
   }
 }
 

Passing values from the command line looks like this:

 java -jar MyJarName.jar full.name.of.MY_PROPERTY=someValue

Here is a complete example of using command line arguments.

This is a Standard Loader

Like all StandardLoader's, this loader is intended to be auto-created by AndHow. The set of standard loaders and their order can bet set via the AndHowConfiguration.setStandardLoaders() methods. Other loaders which don't implement the StandardLoader interface can be inserted into the load order via the AndHowConfiguration.insertLoaderBefore/After().

Author:

ericeverman

Field Summary

Fields inherited from class org.yarnandtail.andhow.load.KeyValuePairLoader

KVP_DELIMITER, unknownPropertyAProblem

Constructor Summary

Constructors

Constructor and Description
StdMainStringArgsLoader() There is no reason to use the constructor in production application code because AndHow creates a single instance on demand at runtime.

Method Summary

Modifier and Type	Method and Description
String	getSpecificLoadDescription() For this particular load, where was info loaded from? This may vary from run to run based on config params.

Methods inherited from class org.yarnandtail.andhow.load.KeyValuePairLoader

getLoaderDialect, getLoaderType, isTrimmingRequiredForStringValues, isUnknownPropertyAProblem, load, releaseResources, setKeyValuePairs, setKeyValuePairs, setUnknownPropertyAProblem

Methods inherited from class org.yarnandtail.andhow.load.BaseLoader

attemptToAdd, attemptToAdd, attemptToAdd, attemptToAddIfNotDuplicate, createValue, findDuplicateProperty, getClassConfig, getConfigSamplePrinter, getInstanceConfig, mapNametoProperty

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.yarnandtail.andhow.api.Loader

getClassConfig, getConfigSamplePrinter, getInstanceConfig, getLoaderDialect, getLoaderType, isTrimmingRequiredForStringValues, load, releaseResources

Constructor Detail

StdMainStringArgsLoader

public StdMainStringArgsLoader()

There is no reason to use the constructor in production application code because AndHow creates a single instance on demand at runtime.

Method Detail

getSpecificLoadDescription

public String getSpecificLoadDescription()

Description copied from interface: Loader

For this particular load, where was info loaded from? This may vary from run to run based on config params. For instance, The PropFileLoader will look multiple places to find a properties file. This method should return the actual location it was found. Assume the text is prefixed with "This loader loaded from: ". An example would be "/home/user/config/my-props.properties" No ending punctuation should be used.

Specified by:

getSpecificLoadDescription in interface Loader

Overrides:

getSpecificLoadDescription in class KeyValuePairLoader

Returns: