archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-26 22:34:27 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8057113: (fs) Path should have a method to obtain the filename extension

Browse source 
Reviewed-by: rriggs, lancea, mr, alanb
This commit is contained in:
Brian Burkhalter 2022-11-01 21:35:54 +00:00
parent d17bf51f91
commit 50d91a31d4
2 changed files with 145 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

62
src/java.base/share/classes/java/nio/file/Path.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2007, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -31,6 +31,7 @@ import java.net.URI;
import java.nio.file.spi.FileSystemProvider;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Objects;
/**
* An object that may be used to locate a file in a file system. It will
@ -49,7 +50,7 @@ import java.util.NoSuchElementException;
* file system. {@code Path} defines the {@link #getFileName() getFileName},
* {@link #getParent getParent}, {@link #getRoot getRoot}, and {@link #subpath
* subpath} methods to access the path components or a subsequence of its name
* elements.
* elements, and {@link #getExtension() getExtension} to obtain its extension.
*
* <p> In addition to accessing the components of a path, a {@code Path} also
* defines the {@link #resolve(Path) resolve} and {@link #resolveSibling(Path)
@ -248,6 +249,63 @@ public interface Path
*/
Path getFileName();
/**
* Returns the file extension of this path's file name as a {@code String}.
* The extension is derived from this {@code Path} by obtaining the
* {@linkplain #getFileName file name element}, deriving its {@linkplain
* #toString string representation}, and then extracting a substring
* determined by the position of a period character ('.', U+002E FULL STOP)
* within the file name string. If the file name element is {@code null},
* or if the file name string does not contain a period character, or if
* the only period in the file name string is its first character, then
* the extension is {@code null}. Otherwise, the extension is the substring
* after the last period in the file name string. If this last period is
* also the last character in the file name string, then the extension is
* {@linkplain String#isEmpty empty}.
*
* @implSpec
* The default implementation is equivalent for this path to:
* <pre>{@code
* int lastPeriod = fileName.lastIndexOf('.');
* if (lastPeriod <= 0)
* return null;
* return (lastPeriod == fileName.length() - 1)
* ? ""
* : fileName.substring(lastPeriod + 1);
* }</pre>
*
* @return the file name extension of this path, which might be the
* empty string, or {@code null} if no extension is found
*
* @since 20
*/
default String getExtension() {
Path fileName = getFileName();
if (fileName == null)
return null;
String fileNameString = fileName.toString();
int length = fileNameString.length();
// An empty or unity length file name string has a null extension
if (length > 1) {
int lastPeriodIndex = fileNameString.lastIndexOf('.');
// Indeterminate if there is no period character or
// only the first character is a period character
if (lastPeriodIndex > 0) {
if (lastPeriodIndex == length - 1) {
// empty string
return "";
} else {
return fileNameString.substring(lastPeriodIndex + 1);
}
}
}
return null;
}
/**
* Returns the <em>parent path</em>, or {@code null} if this path does not
* have a parent.