# Package org.apache.tapestry5.commons.util

- Class Summary
  Class | Description
  --- | ---
  AbstractMessages | Abstract implementation of `Messages` that doesn't know where values come from (that information is supplied in a subclass, via the `AbstractMessages.valueForKey(String)` method).
  AvailableValues | Used (as part of a `UnknownValueException` to identify what available values are present.
  CaseInsensitiveMap<V> | An mapped collection where the keys are always strings and access to values is case-insensitive.
  CollectionFactory | Static factory methods to ease the creation of new collection types (when using generics).
  CommonsUtils | Some utility methods used in different Tapestry subprojects.
  ExceptionUtils | Contains static methods useful for manipulating exceptions.
  IntegerRange | Represents a sequence of integer values, either ascending or descending.
  MultiKey | Combines multiple values to form a single composite key.
  Stack<E> | A simple, streamlined implementation of `Stack`.
  StrategyRegistry<A> | A key component in implementing the "Gang of Four" Strategy pattern.
  StringToEnumCoercion<T extends java.lang.Enum> | A `Coercion` for converting strings into an instance of a particular enumerated type.
  TimeInterval | Used to represent a period of time, specifically as a configuration value.
  VersionUtils | Utility methods related to managing framework version numbers.

- Exception Summary
  Exception | Description
  --- | ---
  CoercionFailedException | Exception used when a `Coercion` throws an exception while trying to coerce a value.
  CoercionNotFoundException | Exception used when `TypeCoercer` doesn't find a coercion from a type to another.
  DifferentClassVersionsException | Exception used when trying to assemble a page but different versions of the same class are found.
  UnknownValueException | Special exception used when a value (typically from a map) is referenced that does not exist.