# EnvironmentFilter
Date: 2013-02-18

## org.simpleframework.xml.filter
Class EnvironmentFilter

    java.lang.Object
      org.simpleframework.xml.filter.EnvironmentFilter

All Implemented Interfaces:
  Filter

    public class EnvironmentFilter

extends java.lang.Object
implements Filter

The `EnvironmentFilter` object is used to provide a filter that will replace the specified values with an environment variable from the OS. This can be given a delegate filter which can be used to resolve replacements should the value requested not match an environment variable from the OS.

Author:
  Niall Gallagher

Constructor Summary
`EnvironmentFilter()` Constructor for the `EnvironmentFilter` object.
`EnvironmentFilter(Filter filter)` Constructor for the `EnvironmentFilter` object.

Method Summary
`java.lang.String` `replace(java.lang.String text)` Replaces the text provided with the value resolved from the environment variables.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### EnvironmentFilter

    public EnvironmentFilter()

  Constructor for the `EnvironmentFilter` object. This creates a filter that resolves replacements using environment variables. Should the environment variables not contain the requested mapping this will return a null value.

### EnvironmentFilter

    public EnvironmentFilter(Filter filter)

  Constructor for the `EnvironmentFilter` object. This creates a filter that resolves replacements using environment variables. Should the environment variables not contain the requested mapping this will delegate to the specified filter.

  Parameters:
    `filter` - the filter delegated to should resolution fail

Method Detail

### replace

    public java.lang.String replace(java.lang.String text)

  Replaces the text provided with the value resolved from the environment variables. If the environment variables fail this will delegate to the specified `Filter` if it is not a null object. If no match is found a null is returned.

  Specified by:
    `replace` in interface `Filter`
  Parameters:
    `text` - this is the text value to be replaced
  Returns:
    this will return the replacement text resolved