de.unkrig.commons.file.filetransformation

Interface FileTransformer

All Known Implementing Classes:

DirectoryTransformer, FileContentsTransformer, ProxyFileTransformer, SelectiveFileTransformer

public interface FileTransformer

See Also:

transform(String, File, File, Mode)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	FileTransformer.Mode

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.RuntimeException	NOT_IDENTICAL Thrown by transform(String, File, File, FileTransformer.Mode.CHECK); indicates that when that method would be invoked with mode FileTransformer.Mode.TRANSFORM, its output would not be identical with its input.
static java.lang.Runnable	THROW_NOT_IDENTICAL A Runnable that simply throws NOT_IDENTICAL.

Method Summary

Modifier and Type	Method and Description
void	transform(java.lang.String path, java.io.File in, java.io.File out, FileTransformer.Mode mode) Creates the file out, based on the file in.

Field Detail

NOT_IDENTICAL

static final java.lang.RuntimeException NOT_IDENTICAL

Thrown by transform(String, File, File, FileTransformer.Mode.CHECK); indicates that when that method would be invoked with mode FileTransformer.Mode.TRANSFORM, its output would not be identical with its input. That can only be the case for an "in-place" transformation.

THROW_NOT_IDENTICAL

static final java.lang.Runnable THROW_NOT_IDENTICAL

A Runnable that simply throws NOT_IDENTICAL.

Method Detail

transform

void transform(java.lang.String path,
               java.io.File in,
               java.io.File out,
               FileTransformer.Mode mode)
        throws java.io.IOException

Creates the file out, based on the file in. Iff in.equals(out) ('in-place transformation'), then the original file remains unchanged, is modified, or replaced with a new file.

The precise contract is as follows:

• If mode == Mode.CHECK, then this method merely checks whether the content of the file would change, and, if so, complete normally, otherwise it would throw NOT_IDENTICAL.
• Otherwise, if !in.equals(out) ("out-of-place transformation"), out is created, based on in. (Parameter mode is ignored.) (If this method throws an exception, then it must not leave a file out behind.)
• Otherwise, the file is left unchanged, is modified, or is replaced with a new file. If mode == Mode.CHECK_AND_TRANSFORM, then the method attempts to avoid unnecessary i/o and processing by first checking whether the file requires any modifications before applying them. (If this method throws an exception, then it must revert the file to its original state as far as is reasonably possible.) /li>

Parameters:

path - A text designating the input file; typically, but not necessarily identical with in.getPath()

in - The input file to read

out - The output file to create; irrelevant iff mode == FileTransformer.Mode.CHECK

Throws:

java.lang.RuntimeException - NOT_IDENTICAL iff mode == FileTransformer.Mode.CHECK and the output produced by transform(String, File, File, Mode) would not be identical with the input

java.io.IOException

See Also:

NOT_IDENTICAL, FileTransformer.Mode.TRANSFORM, FileTransformer.Mode.CHECK, FileTransformer.Mode.CHECK_AND_TRANSFORM