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

## Interface Algorithm

- All Known Implementing Classes:
    `ChecksumAlgorithm`, `DigestAlgorithm`, `HashvalueAlgorithm`, `LastModifiedAlgorithm`

      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
    Modifier and Type | Method | Description
    --- | --- | ---
    `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