org.yarnandtail.andhow.load

Class BaseLoader

java.lang.Object

org.yarnandtail.andhow.load.BaseLoader

All Implemented Interfaces:

Loader

Direct Known Subclasses:

BaseFixedValueLoader, BaseKeyValuePairLoader, BaseMapLoader, PropFileBaseLoader, StdJndiLoader

public abstract class BaseLoader
extends Object
implements Loader

Base implementation of a Loader that provides some basic services and behavior that all loader can share and use.

Constructor Summary

Constructors

Constructor and Description
BaseLoader()

Method Summary

Modifier and Type	Method and Description
protected void	attemptToAdd(PropertyConfigurationInternal appConfigDef, List<ValidatedValue> values, ProblemList<Problem> loaderProblems, Property prop, Object value) Util method to attempt to load an object of an unknown type to a property.
protected void	attemptToAdd(PropertyConfigurationInternal appConfigDef, List<ValidatedValue> values, ProblemList<Problem> loaderProblems, String key, Object value) Util method to load an Object value to a named Property.
protected void	attemptToAdd(PropertyConfigurationInternal appConfigDef, List<ValidatedValue> values, ProblemList<Problem> loaderProblems, String key, String strValue) Util method to load a String to a property by name.
protected void	attemptToAddIfNotDuplicate(PropertyConfigurationInternal appConfigDef, List<ValidatedValue> values, ProblemList<Problem> loaderProblems, ValidatedValue validatedValue) Adds the ValidatedValue to the VV list if it is not a duplicate.
protected <T> ValidatedValue	createValue(Property<T> prop, String untrimmedString) Central method for parsing Strings into a Property value.
protected ValidatedValue	findDuplicateProperty(ValidatedValue current, List<ValidatedValue> values)
Class<?>	getClassConfig() Returns a PropertyGroup used to globally configure a class of Loader.
SamplePrinter	getConfigSamplePrinter() Returns a ConfigSamplePrinter, which can be used to print a configuration sample for this Loader.
List<Property>	getInstanceConfig() A list of properties that the user has specified as being configuration properties for this Loader.
protected Property	mapNametoProperty(PropertyConfigurationInternal appConfigDef, String name) Maps the passed Property name or alias to a Property or null if it cannot be found.
void	releaseResources() Release any resources held by this loader.

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

getLoaderDialect, getLoaderType, getSpecificLoadDescription, isFlaggable, isTrimmingRequiredForStringValues, load

Constructor Detail

BaseLoader

public BaseLoader()

Method Detail

getClassConfig

public Class<?> getClassConfig()

Description copied from interface: Loader

Returns a PropertyGroup used to globally configure a class of Loader. For loaders that are intended to be single instance and thus have a single set of configuration properties, this method allows them to report their configuration PropertyGroup so it can be included in the list of registered groups. Examples of such loaders would be as system wide naming services like JNDI or a JNDI derivative (like LDAP via JNDI). The Group returned from this method will be registered and included in generated sample config files. Loader classes should provide default Property values so they work w/o configuration if possible. For configuration properties that should vary between instances of the same loader class, the loader class should accept Properties in its constructor. Those properties should then be returned by getInstanceConfig().

Specified by:

getClassConfig in interface Loader

Returns:

A PropertyGroup that defines configuration for this class, or null if there is none.

getInstanceConfig

public List<Property> getInstanceConfig()

Description copied from interface: Loader

A list of properties that the user has specified as being configuration properties for this Loader. Typically these Properties have been specified in the Loader constructor or builder. An example usage would be passing in a Property that specifies the location of a properties file to read from. This is the preferred way to configure a loader because its clear to the user and it allows each instance of a loader to be configured differently, e.g., so PropertyFile loaders that load from different locations. Any Properties returned from this method must have been registered for configuration.

Specified by:

getInstanceConfig in interface Loader

Returns:

Never null. Either an empty list or populated.

getConfigSamplePrinter

public SamplePrinter getConfigSamplePrinter()

Description copied from interface: Loader

Returns a ConfigSamplePrinter, which can be used to print a configuration sample for this Loader. This method may return null if there is no sample printer for this loader.

Specified by:

getConfigSamplePrinter in interface Loader

Returns:

attemptToAdd

protected void attemptToAdd(PropertyConfigurationInternal appConfigDef,
                            List<ValidatedValue> values,
                            ProblemList<Problem> loaderProblems,
                            String key,
                            String strValue)

Util method to load a String to a property by name.

Used for text based loaders.

Parameters:

appConfigDef - Used to look up the property name for find the actual property

values - List of PropertyValues to add to, which should be only the value of this loader.

loaderProblems - A list of Problems to add to if there is a loader related problem

key - The property name

strValue - The property value

attemptToAdd

protected void attemptToAdd(PropertyConfigurationInternal appConfigDef,
                            List<ValidatedValue> values,
                            ProblemList<Problem> loaderProblems,
                            String key,
                            Object value)

Util method to load an Object value to a named Property.

Intended for code-based loaders where Property names are specified with Object based keys. This would happen with hardcoded / in-code loaders, likely during testing, where property values can be specified as real objects, but the Properties themselves may not all be visible, so names are used instead of Property references.

Parameters:

appConfigDef - Used to look up the property name for find the actual property

values - List of PropertyValues to add to, which should be only the value of this loader.

loaderProblems - A list of Problems to add to if there is a loader related problem

key - The property name

value - The property value as an Object, already of the expected type for the Property.

attemptToAdd

protected void attemptToAdd(PropertyConfigurationInternal appConfigDef,
                            List<ValidatedValue> values,
                            ProblemList<Problem> loaderProblems,
                            Property prop,
                            Object value)

Util method to attempt to load an object of an unknown type to a property.

Used for object based loaders where value are not in text form. This loader assumes the passed property is a valid property to load to, but it will check to make sure it is not null, which is not treated as an error.

Parameters:

appConfigDef - Used to look up the property name for find the actual property

values - List of PropertyValues to add to, which should be only the value of this loader.

loaderProblems - A list of LoaderProblems to add to if there is a loader related problem

prop - The Property to load to

value - The Object to be loaded to this property. If a String and that does not match the Property type, parsing is attempted to convert it.

attemptToAddIfNotDuplicate

protected void attemptToAddIfNotDuplicate(PropertyConfigurationInternal appConfigDef,
                                          List<ValidatedValue> values,
                                          ProblemList<Problem> loaderProblems,
                                          ValidatedValue validatedValue)

Adds the ValidatedValue to the VV list if it is not a duplicate. This is the actual 'load' moment of the Loader: Adding it to this list means that the value has been loaded.

Loader subclasses should use the other attemptToAdd methods - this one is invoked by those.

Parameters:

appConfigDef - Used to look up the property name for find the actual property

values - List of PropertyValues to add to, which should be only the value of this loader.

loaderProblems - A list of Problems to add to if there is a loader related problem

validatedValue - The validated value to load, which may be null which is a no-op.

findDuplicateProperty

protected ValidatedValue findDuplicateProperty(ValidatedValue current,
                                               List<ValidatedValue> values)

createValue

protected <T> ValidatedValue createValue(Property<T> prop,
                                         String untrimmedString)
                                  throws ParsingException

Central method for parsing Strings into a Property value.

This method throws a ParsingException if the value cannot be parsed into the destination type. If that happens, the caller should consider it a LoaderProblem, not a ValueProblem.

If a loader bypasses this method, it must replicate the trimming and (non) validation logic in this method to ensure String are trimmed appropriately. Specifically:

• For Properties of destination type String, this method applies the Property's trimmer only if Loader.isTrimmingRequiredForStringValues() returns true.
• For non-String type Properties, the Property's trimmer is always applied.
• After trimming (or not), the Property's ValueType.parse() method is called.

Type Parameters:

T - The destination type of the Property (i.e., an IntProp is Integer).

Parameters:

prop - The Property the untrimmedString String holds the value for

untrimmedString - A String to be parsed into the destination type of the Property.

Returns:

A ValidatedValue containing the Property and the resulting value. Validation has not yet been applied to the ValidatedValue, so it won't have any Problems listed.

Throws:

ParsingException - If the String value cannot be parsed into the destination type.

mapNametoProperty

protected Property mapNametoProperty(PropertyConfigurationInternal appConfigDef,
                                     String name)

Maps the passed Property name or alias to a Property or null if it cannot be found.

Parameters:

appConfigDef - The AppConfig

name - The name, which will be trimmed and converted to an effective name.

Returns:

The Property or null if it cannot be found.

releaseResources

public void releaseResources()

Description copied from interface: Loader

Release any resources held by this loader. Loaders have done their job after loading values to properties. However, they may be held in memory for auditing and reporting. To prevent holding additional resources in memory, this method is called after loading is complete.

Specified by:

releaseResources in interface Loader