# SystemFilter
Date: 2013-02-18

## org.simpleframework.xml.filter
Class SystemFilter

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

All Implemented Interfaces:
  Filter

    public class SystemFilter

extends java.lang.Object
implements Filter

The `SystemFilter` object is used to provide a filter that will replace the specified values with system properties. This can be given a delegate filter which can be used to resolve replacements should the value requested not match a property.

Author:
  Niall Gallagher

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

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

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

Constructor Detail

### SystemFilter

    public SystemFilter()

  Constructor for the `SystemFilter` object. This creates a filter that will resolve replacements using system properties. Should the system properties not contain the requested mapping this will return a null value.

### SystemFilter

    public SystemFilter(Filter filter)

  Constructor for the `SystemFilter` object. This creates a filter that will resolve replacements using system properties. Should the system properties not contain the requested mapping this delegates to the specified filter.

  Parameters:
    `filter` - the filter delegated to if resolution fails

Method Detail

### replace

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

  Replaces the text provided with the value resolved from the system properties. If the system properties fails 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