Java - FilePermission Class

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Introduction

The Java FilePermission class represents access to a file or directory.It consists of a pathname and a set of actions valid for that pathname. Following are the important points about FilePermission −

• The actions to be granted are passed to the constructor in a string containing a list of one or more comma-separated keywords. The possible keywords are "read", "write", "execute", and "delete".

• Code can always read a file from the same directory it's in (or a subdirectory of that directory); it does not need explicit permission to do so.

Class declaration

Following is the declaration for Java.io.FilePermission class −

 public final class FilePermission extends Permission implements Serializable 

Class constructors

Class methods

Methods inherited

This class inherits methods from the following classes −

• Java.io.Permission
• Java.io.Object

Example - Comparing Two Identical FilePermission Objects

The following example shows the usage of Java FilePermission equals(Object obj) method.

FilePermissionDemo.java

 package com.tutorialspoint; import java.io.FilePermission; public class FilePermissionDemo { public static void main(String[] args) { // Creating two identical FilePermission objects FilePermission fp1 = new FilePermission("C:\\Users\\Documents\\file.txt", "read,write"); FilePermission fp2 = new FilePermission("C:\\Users\\Documents\\file.txt", "read,write"); // Checking equality if (fp1.equals(fp2)) { System.out.println("Both FilePermission objects are equal."); } else { System.out.println("FilePermission objects are not equal."); } } } 

Output

Let us compile and run the above program, this will produce the following result−

 Both FilePermission objects are equal. 

Explanation

• Two FilePermission objects (fp1 and fp2) are created with the same file path and same actions (read,write).

• The equals() method is used to compare them.

• Since both objects are identical, it prints: Both FilePermission objects are equal.

Example - Retrieving Read and Write Permissions

The following example shows the usage of Java FilePermission getActions() method.

FilePermissionDemo.java

 package com.tutorialspoint; import java.io.FilePermission; public class FilePermissionDemo { public static void main(String[] args) { // Creating a FilePermission object with "read" and "write" actions FilePermission filePermission = new FilePermission("example.txt", "read,write"); // Getting and displaying the actions associated with this permission String actions = filePermission.getActions(); System.out.println("Allowed Actions: " + actions); } } 

Output

Let us compile and run the above program, this will produce the following result−

 Allowed Actions: read,write 

Explanation

• Creates a FilePermission object for "example.txt" with "read" and "write" permissions.

• Calls getActions() to retrieve the assigned actions.

Example - Usage of FilePermission implies(Permission p) method

The following example shows the usage of Java FilePermission implies(Permission p) method.

FilePermissionDemo.java

 package com.tutorialspoint; import java.io.FilePermission; import java.io.IOException; public class FilePermissionDemo { public static void main(String[] args) throws IOException { FilePermission fp = null; FilePermission fp1 = null; FilePermission fp2 = null; FilePermission fp3 = null; boolean bool = false; try { // create new file permissions fp = new FilePermission("test.txt", "read"); fp1 = new FilePermission("test.txt", "write"); fp2 = new FilePermission("test1.txt", "read"); fp3 = new FilePermission("test.txt", "read"); // tests if implied by this object bool = fp.implies(fp1); // print System.out.println(bool); bool = fp.implies(fp2); System.out.println(bool); bool = fp.implies(fp3); System.out.print(bool); } catch(Exception ex) { // if an error occurs ex.printStackTrace(); } } } 

Output

Let us compile and run the above program, this will produce the following result−

 false false true