186 Java PropertyPermission Class

Introduction

The Java PropertyPermission class is a class for property permissions. Following are the important points about PropertyPermission −

• The name is the name of the property ("java.home", "os.name", etc).

• The naming convention follows the hierarchical property naming convention.An asterisk may appear at the end of the name, following a ".", or by itself, to signify a wildcard match.For example: "java.*" or "*" is valid, "*java" or "a*b" is not valid.

Class declaration

Following is the declaration for java.util.PropertyPermission class −

public final class PropertyPermission
   extends BasicPermission

Class constructors

Sr.No.	Constructor & Description
1	PropertyPermission(String name, String actions) This creates a new PropertyPermission object with the specified name.

Class methods

Sr.No.	Method & Description
1	boolean equals(Object obj) This method checks two PropertyPermission objects for equality.
2	String getActions() This method returns the "canonical string representation" of the actions.
3	int hashCode() This method returns the hash code value for this object.
4	boolean implies(Permission p) This method checks if this PropertyPermission object "implies" the specified permission.
5	PermissionCollection newPermissionCollection() This method returns a returns a new PermissionCollection object for storing PropertyPermission objects.

Methods inherited

This class inherits methods from the following classes −

• java.util.Permission
• java.util.Object

Checking a PropertyPermission Object for read/write actions Example

The following example shows the usage of Java PropertyPermission getActions() method to check a permission object. We've built a PropertyPermission object, and then check the permission to be read or write.

package com.codeheap;

import java.util.PropertyPermission;

public class PropertyPermissionDemo {
   private static PropertyPermission permission;
   
   public static void main(String[] args) {

      // Build property permissions
      permission = new PropertyPermission("java.home.*", "read,write");

      // Check permissions
      checkFilePermissions("java.home.usr");
   }

   private static void checkFilePermissions(String path) {
      
      // Check permission given name
      if(path.matches(permission.getName())) {

         // Get actions list
         String actions = permission.getActions();
         
         // Match read write actions
         if(actions.contains("read"))
         System.out.println("Has permissions on "+path+" for read");
         
         if(actions.contains("write"))
         System.out.println("Has permissions on "+path+" for write");
      }
   }
}

Output

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

Has permissions on java.home.usr for read
Has permissions on java.home.usr for write