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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN""http://www.w3.org/TR/REC-html40/frameset.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc on Thu Apr 27 23:36:01 PDT 2000 --><TITLE>Java 2 Platform SE v1.3: Class PermissionCollection</TITLE><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"></HEAD><BODY BGCOLOR="white"><!-- ========== START OF NAVBAR ========== --><A NAME="navbar_top"><!-- --></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="class-use/PermissionCollection.html"><FONT CLASS="NavBarFont1"><B>Use</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-files/index-1.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM><b>Java<sup><font size=-2>TM</font></sup> 2 Platform<br>Std. Ed. v1.3</b></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../java/security/Permission.html"><B>PREV CLASS</B></A> <A HREF="../../java/security/Permissions.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="PermissionCollection.html" TARGET="_top"><B>NO FRAMES</B></A></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: INNER | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><!-- =========== END OF NAVBAR =========== --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">java.security</FONT><BR>Class PermissionCollection</H2><PRE><A HREF="../../java/lang/Object.html">java.lang.Object</A> | +--<B>java.security.PermissionCollection</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../java/io/Serializable.html">Serializable</A></DD></DL><DL><DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../java/security/Permissions.html">Permissions</A></DD></DL><HR><DL><DT>public abstract class <B>PermissionCollection</B><DT>extends <A HREF="../../java/lang/Object.html">Object</A><DT>implements <A HREF="../../java/io/Serializable.html">Serializable</A></DL><P>Abstract class representing a collection of Permission objects. <p>With a PermissionCollection, you can: <UL> <LI> add a permission to the collection using the <code>add</code> method. <LI> check to see if a particular permission is implied in the collection, using the <code>implies</code> method. <LI> enumerate all the permissions, using the <code>elements</code> method. </UL> <P> <p>When it is desirable to group together a number of Permission objects of the same type, the <code>newPermissionCollection</code> method on that particular type of Permission object should first be called. The default behavior (from the Permission class) is to simply return null. Subclasses of class Permission override the method if they need to store their permissions in a particular PermissionCollection object in order to provide the correct semantics when the <code>PermissionCollection.implies</code> method is called. If a non-null value is returned, that PermissionCollection must be used. If null is returned, then the caller of <code>newPermissionCollection</code> is free to store permissions of the given type in any PermissionCollection they choose (one that uses a Hashtable, one that uses a Vector, etc). <p>The PermissionCollection returned by the <code>Permission.newPermissionCollection</code> method is a homogeneous collection, which stores only Permission objects for a given Permission type. A PermissionCollection may also be heterogenous. For example, Permissions is a PermissionCollection subclass that represents a collection of PermissionCollections. That is, its members are each a homogeneous PermissionCollection. For example, a Permissions object might have a FilePermissionCollection for all the FilePermission objects, a SocketPermissionCollection for all the SocketPermission objects, and so on. Its <code>add</code> method adds a permission to the appropriate collection. <p>Whenever a permission is added to a heterogeneous PermissionCollection such as Permissions, and the PermissionCollection doesn't yet contain a PermissionCollection of the specified permission's type, the PermissionCollection should call the <code>newPermissionCollection</code> method on the permission's class to see if it requires a special PermissionCollection. If <code>newPermissionCollection</code> returns null, the PermissionCollection is free to store the permission in any type of PermissionCollection it desires (one using a Hastable, one using a Vector, etc.). For example, the Permissions object uses a default PermissionCollection implementation that stores the permission objects in a Hashtable.<P><DL><DT><B>See Also: </B><DD><A HREF="../../java/security/Permission.html"><CODE>Permission</CODE></A>, <A HREF="../../java/security/Permissions.html"><CODE>Permissions</CODE></A>, <A HREF="../../serialized-form.html#java.security.PermissionCollection">Serialized Form</A></DL><HR><P><!-- ======== INNER CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#PermissionCollection()">PermissionCollection</A></B>()</CODE><BR> </TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>abstract void</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#add(java.security.Permission)">add</A></B>(<A HREF="../../java/security/Permission.html">Permission</A> permission)</CODE><BR> Adds a permission object to the current collection of permission objects.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>abstract <A HREF="../../java/util/Enumeration.html">Enumeration</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#elements()">elements</A></B>()</CODE><BR> Returns an enumeration of all the Permission objects in the collection.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>abstract boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#implies(java.security.Permission)">implies</A></B>(<A HREF="../../java/security/Permission.html">Permission</A> permission)</CODE><BR> Checks to see if the specified permission is implied by the collection of Permission objects held in this PermissionCollection.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#isReadOnly()">isReadOnly</A></B>()</CODE><BR> Returns true if this PermissionCollection object is marked as readonly.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../java/security/PermissionCollection.html#setReadOnly()">setReadOnly</A></B>()</CODE><BR> Marks this PermissionCollection object as "readonly".</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../java/lang/String.html">String</A></CODE></FONT></TD>⌨️ 快捷键说明
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