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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.5.0_02) on Wed Mar 22 19:19:06 PST 2006 --><TITLE>JCSystem (Java Card API and Subsets)</TITLE><META NAME="keywords" CONTENT="javacard.framework.JCSystem class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="JCSystem (Java Card API and Subsets)";}</SCRIPT><NOSCRIPT></NOSCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=2 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <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/JCSystem.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-all.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 Card </b><br><font size="-1">v2.2.2</font></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../javacard/framework/ISOException.html" title="class in javacard.framework"><B>PREV CLASS</B></A> <A HREF="../../javacard/framework/MultiSelectable.html" title="interface in javacard.framework"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html?javacard/framework/JCSystem.html" target="_top"><B>FRAMES</B></A> <A HREF="JCSystem.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#field_summary">FIELD</A> | CONSTR | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | CONSTR | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">javacard.framework</FONT><BR>Class JCSystem</H2><PRE><A HREF="../../java/lang/Object.html" title="class in java.lang">java.lang.Object</A> <IMG SRC="../../resources/inherit.gif" ALT="extended by "><B>javacard.framework.JCSystem</B></PRE><HR><DL><DT><PRE>public final class <B>JCSystem</B><DT>extends <A HREF="../../java/lang/Object.html" title="class in java.lang">Object</A></DL></PRE><P>The <code>JCSystem</code> class includes a collection of methods to control applet execution, resource management, atomic transaction management, object deletion mechanism and inter-applet object sharing in the Java Card environment. All methods in <code>JCSystem</code> class are static methods.<p> This class also includes methods to control the persistence and transience of objects. The term <em>persistent</em> means that objects and their values persist from one CAD session to the next, indefinitely. Persistent object values are updated atomically using transactions.<p> The <code>makeTransient...Array()</code> methods can be used to create <em>transient</em> arrays. Transient array data is lost (in an undefined state, but the real data is unavailable) immediately upon power loss, and is reset to the default value at the occurrence of certain events such as card reset or deselect. Updates to the values of transient arrays are not atomic and are not affected by transactions. <p> The Java Card runtime environment maintains an atomic transaction commit buffer which is initialized on card reset (or power on). When a transaction is in progress, the Java Card runtime environment journals all updates to persistent data space into this buffer so that it can always guarantee, at commit time, that everything in the buffer is written or nothing at all is written. The <code>JCSystem</code> includes methods to control an atomic transaction. See <em>Runtime Environment Specification for the Java Card Platform</em> for details. <p><P><P><DL><DT><B>See Also:</B><DD><A HREF="../../javacard/framework/SystemException.html" title="class in javacard.framework"><CODE>SystemException</CODE></A>, <A HREF="../../javacard/framework/TransactionException.html" title="class in javacard.framework"><CODE>TransactionException</CODE></A>, <A HREF="../../javacard/framework/Applet.html" title="class in javacard.framework"><CODE>Applet</CODE></A></DL><HR><P><!-- =========== FIELD SUMMARY =========== --><A NAME="field_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Field Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#CLEAR_ON_DESELECT">CLEAR_ON_DESELECT</A></B></CODE><BR> This event code indicates that the contents of the transient object are cleared to the default value on applet deselection event or in <code>CLEAR_ON_RESET</code> cases.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#CLEAR_ON_RESET">CLEAR_ON_RESET</A></B></CODE><BR> This event code indicates that the contents of the transient object are cleared to the default value on card reset (or power on) event.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#MEMORY_TYPE_PERSISTENT">MEMORY_TYPE_PERSISTENT</A></B></CODE><BR> Constant to indicate persistent memory type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#MEMORY_TYPE_TRANSIENT_DESELECT">MEMORY_TYPE_TRANSIENT_DESELECT</A></B></CODE><BR> Constant to indicate transient memory of CLEAR_ON_DESELECT type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#MEMORY_TYPE_TRANSIENT_RESET">MEMORY_TYPE_TRANSIENT_RESET</A></B></CODE><BR> Constant to indicate transient memory of CLEAR_ON_RESET type.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#NOT_A_TRANSIENT_OBJECT">NOT_A_TRANSIENT_OBJECT</A></B></CODE><BR> This event code indicates that the object is not transient.</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2"><B>Method Summary</B></FONT></TH></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#abortTransaction()">abortTransaction</A></B>()</CODE><BR> Aborts the atomic transaction.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#beginTransaction()">beginTransaction</A></B>()</CODE><BR> Begins an atomic transaction.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#commitTransaction()">commitTransaction</A></B>()</CODE><BR> Commits an atomic transaction.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static <A HREF="../../javacard/framework/AID.html" title="class in javacard.framework">AID</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#getAID()">getAID</A></B>()</CODE><BR> Returns the Java Card runtime environment-owned instance of the <code>AID</code> object associated with the current applet context, or <code>null</code> if the <code>Applet.register()</code> method has not yet been invoked.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static <A HREF="../../javacard/framework/Shareable.html" title="interface in javacard.framework">Shareable</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#getAppletShareableInterfaceObject(javacard.framework.AID, byte)">getAppletShareableInterfaceObject</A></B>(<A HREF="../../javacard/framework/AID.html" title="class in javacard.framework">AID</A> serverAID, byte parameter)</CODE><BR> Called by a client applet to get a server applet's shareable interface object.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static byte</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#getAssignedChannel()">getAssignedChannel</A></B>()</CODE><BR> This method is called to obtain the logical channel number assigned to the currently selected applet instance.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>static short</CODE></FONT></TD><TD><CODE><B><A HREF="../../javacard/framework/JCSystem.html#getAvailableMemory(byte)">getAvailableMemory</A></B>(byte memoryType)</CODE><BR> Obtains the amount of memory of the specified type that is available to the applet.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor">⌨️ 快捷键说明
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