java.util: public final class: PropertyPermission

java.util
public final class: PropertyPermission [javadoc | source]

java.lang.Object
   java.security.Permission
      java.security.BasicPermission
         java.util.PropertyPermission

All Implemented Interfaces:
Serializable, Guard

This class is for property permissions.

The name is the name of the property ("java.home", "os.name", etc). The naming convention follows the hierarchical property naming convention. Also, 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.

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" and "write". Their meaning is defined as follows:

read: read permission. Allows System.getProperty to be called.
write: write permission. Allows System.setProperty to be called.

The actions string is converted to lowercase before processing.

Care should be taken before granting code permission to access certain system properties. For example, granting permission to access the "java.home" system property gives potentially malevolent code sensitive information about the system environment (the Java installation directory). Also, granting permission to access the "user.name" and "user.home" system properties gives potentially malevolent code sensitive information about the user environment (the user's account name and home directory).

Also see:

java.security.BasicPermission

java.security.Permission

java.security.Permissions

java.security.PermissionCollection

java.lang.SecurityManager

author: Roland - Schemers

since: 1.2 -

serial: exclude -

Constructor:

Constructor:
public PropertyPermission(String name, String actions) { super(name,actions); init(getMask(actions)); } Creates a new PropertyPermission object with the specified name. The name is the name of the system property, and actions contains a comma-separated list of the desired actions granted on the property. Possible actions are "read" and "write". Parameters: `name` - the name of the PropertyPermission. `actions` - the actions string. Throws: `NullPointerException` - if `name` is `null`. `IllegalArgumentException` - if `name` is empty or if `actions` is invalid.

 public PropertyPermission(String name,
    String actions) {
        super(name,actions);
        init(getMask(actions));
}

actions

Parameters:

name - the name of the PropertyPermission.

actions - the actions string.

Throws:

NullPointerException - if name is null.

IllegalArgumentException - if name is empty or if actions is invalid.

Method from java.util.PropertyPermission Summary:
equals, getActions, getActions, getMask, hashCode, implies, newPermissionCollection

Methods from java.security.BasicPermission:
equals, getActions, getCanonicalName, hashCode, implies, newPermissionCollection

Methods from java.security.Permission:
checkGuard, equals, getActions, getName, hashCode, implies, newPermissionCollection, toString

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.util.PropertyPermission Detail:
public boolean equals(Object obj) { if (obj == this) return true; if (! (obj instanceof PropertyPermission)) return false; PropertyPermission that = (PropertyPermission) obj; return (this.mask == that.mask) && (this.getName().equals(that.getName())); } Checks two PropertyPermission objects for equality. Checks that obj is a PropertyPermission, and has the same name and actions as this object.
public String getActions() { if (actions == null) actions = getActions(this.mask); return actions; } Returns the "canonical string representation" of the actions. That is, this method always returns present actions in the following order: read, write. For example, if this PropertyPermission object allows both write and read actions, a call to `getActions` will return the string "read,write".
static String getActions(int mask) { StringBuilder sb = new StringBuilder(); boolean comma = false; if ((mask & READ) == READ) { comma = true; sb.append("read"); } if ((mask & WRITE) == WRITE) { if (comma) sb.append(',"); else comma = true; sb.append("write"); } return sb.toString(); } Return the canonical string representation of the actions. Always returns present actions in the following order: read, write.
int getMask() { return mask; } Return the current action mask. Used by the PropertyPermissionCollection
public int hashCode() { return this.getName().hashCode(); } Returns the hash code value for this object. The hash code used is the hash code of this permissions name, that is, `getName().hashCode()`, where `getName` is from the Permission superclass.
public boolean implies(Permission p) { if (!(p instanceof PropertyPermission)) return false; PropertyPermission that = (PropertyPermission) p; // we get the effective mask. i.e., the "and" of this and that. // They must be equal to that.mask for implies to return true. return ((this.mask & that.mask) == that.mask) && super.implies(that); } Checks if this PropertyPermission object "implies" the specified permission. More specifically, this method returns true if: p is an instanceof PropertyPermission, p's actions are a subset of this object's actions, and p's name is implied by this object's name. For example, "java.*" implies "java.home".
public PermissionCollection newPermissionCollection() { return new PropertyPermissionCollection(); } Returns a new PermissionCollection object for storing PropertyPermission objects.

Method from java.util.PropertyPermission Detail:

 public boolean equals(Object obj) {
        if (obj == this)
            return true;
        if (! (obj instanceof PropertyPermission))
            return false;
        PropertyPermission that = (PropertyPermission) obj;
        return (this.mask == that.mask) &&
            (this.getName().equals(that.getName()));
}

obj

 public String getActions() {
        if (actions == null)
            actions = getActions(this.mask);
        return actions;
}

getActions

 static String getActions(int mask) {
        StringBuilder sb = new StringBuilder();
        boolean comma = false;
        if ((mask & READ) == READ) {
            comma = true;
            sb.append("read");
        }
        if ((mask & WRITE) == WRITE) {
            if (comma) sb.append(',");
            else comma = true;
            sb.append("write");
        }
        return sb.toString();
}

Return the canonical string representation of the actions. Always returns present actions in the following order: read, write.

 int getMask() {
        return mask;
}

Return the current action mask. Used by the PropertyPermissionCollection

 public int hashCode() {
        return this.getName().hashCode();
}

getName().hashCode()

getName

 public boolean implies(Permission p) {
        if (!(p instanceof PropertyPermission))
            return false;
        PropertyPermission that = (PropertyPermission) p;
        // we get the effective mask. i.e., the "and" of this and that.
        // They must be equal to that.mask for implies to return true.
        return ((this.mask & that.mask) == that.mask) && super.implies(that);
}

More specifically, this method returns true if:

p is an instanceof PropertyPermission,
p's actions are a subset of this object's actions, and
p's name is implied by this object's name. For example, "java.*" implies "java.home".

 public PermissionCollection newPermissionCollection() {
        return new PropertyPermissionCollection();
}