org.apache.tools.ant.types.selectors.modifiedselector

## Interface Algorithm

All Known Implementing Classes:
  ChecksumAlgorithm, DigestAlgorithm, HashvalueAlgorithm

    public interface Algorithm

The Algorithm defines how a value for a file is computed. It must be sure that multiple calls for the same file results in the same value. The implementing class should implement a useful toString() method.

Since:
  Ant 1.6
Version:
  2003-09-13

### Method Summary

All Methods Instance Methods Abstract Methods
`java.lang.String` `getValue(java.io.File file)` Get the value for a file.
`boolean` `isValid()` Checks its prerequisites.

### Method Detail

#### isValid

    boolean isValid()

Checks its prerequisites.

Returns:
  true if all is ok, otherwise false.

#### getValue

    java.lang.String getValue(java.io.File file)

Get the value for a file.

Parameters:
  `file` - File object for which the value should be evaluated.
Returns:
  The value for that file