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java语言规范

<p><font size=+1><strong>20.17.20   </strong> <code>public void <code><b>checkWrite</b></code>(int fd)<br>throws SecurityException</code></font>
<p>
<a name="20000"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if creating an output stream using the specified file descriptor is not permitted.
<p><a name="21916"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by one constructor for <code>java.io.FileOutputStream</code> <a href="javaio.doc14.html#29525">(&#167;22.16.3)</a>.<p>
<a name="21920"></a>
The <code>checkWrite</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if creating an output stream from an existing file descriptor is to be permitted with a security manager installed.<p>
<a name="14117"></a>
<p><font size=+1><strong>20.17.21   </strong> <code>public void <code><b>checkWrite</b></code>(String file)<br>throws SecurityException</code></font>
<p>
<a name="20009"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if writing, modifying, creating (for output), or renaming the specified file or directory
is not permitted.
<p><a name="20013"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by two constructors for <code>java.io.FileOutputStream</code> (<a href="javaio.doc14.html#29510">&#167;22.16.1</a>, <a href="javaio.doc14.html#29518">&#167;22.16.2</a>); by two constructors for <code>java.io.RandomAccessFile</code> (<a href="javaio.doc21.html#27788">&#167;22.23.1</a>, <a href="javaio.doc21.html#27799">&#167;22.23.2</a>); and by methods <code>canWrite</code> <a href="javaio.doc22.html#29809">(&#167;22.24.18)</a>, <code>mkdir</code> <a href="javaio.doc22.html#29847">(&#167;22.24.23)</a>, and <code>renameTo</code> <a href="javaio.doc22.html#29875">(&#167;22.24.27)</a> of class <code>java.io.File</code>.<p>
<a name="21924"></a>
The <code>checkWrite</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if write access to a file is to be permitted with a security manager installed.<p>
<a name="14118"></a>
<p><font size=+1><strong>20.17.22   </strong> <code>public void <code><b>checkDelete</b></code>(String file)<br>throws SecurityException</code></font>
<p>
<a name="20018"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if deleting the specified file is not permitted.
<p><a name="20022"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by method <code>delete</code> <a href="javaio.doc22.html#29882">(&#167;22.24.28)</a> of class <code>java.io.File</code>.<p>
<a name="20023"></a>
The <code>checkDelete</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if a file deletion operation is to be permitted with a security manager installed.<p>
<a name="14119"></a>
<p><font size=+1><strong>20.17.23   </strong> <code>public void <code><b>checkConnect</b></code>(String host, int port)<br>	throws SecurityException</code></font>
<p>
<a name="20030"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if connecting to the indicated <code>port</code> of the indicated network <code>host</code> is not permitted.
<p><a name="29737"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by two constructors for class <code>java.net.Socket</code>, methods <code>send</code> and <code>receive</code> of class <code>java.net.DatagramSocket</code>, and methods <code>getByName</code> and <code>getAllByName</code> of class <code>java.net.InetAddress</code>. (These classes are not documented in this specification. See <i>The Java Application Programming Interface</i>.)<p>
<a name="20035"></a>
The <code>checkConnect</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if a network connection is to be permitted with a security manager installed.<p>
<a name="14120"></a>
<p><font size=+1><strong>20.17.24   </strong> <code>public void <code><b>checkListen</b></code>(int port)<br>throws SecurityException</code></font>
<p>
<a name="20039"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if listening to the specified local network <code>port</code> is not permitted.
<p><a name="29786"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by the constructor of one argument for class <code>java.net.DatagramSocket</code> and by the constructors for class <code>java.net.ServerSocket</code>. (These classes are not documented in this specification. See <i>The Java Application Programming Interface</i>.)<p>
<a name="20044"></a>
The <code>checkListen</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if listening to a local network port is to be permitted with a security manager installed.<p>
<a name="14121"></a>
<p><font size=+1><strong>20.17.25   </strong> <code>public void <code><b>checkAccept</b></code>(String host, int port)<br>throws SecurityException</code></font>
<p>
<a name="29810"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if accepting a connection from the indicated <code>port</code> of the indicated network <code>host</code> 
is not permitted.
<p><a name="20052"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by method <code>accept</code> of class <code>java.net.ServerSocket</code>. (This class is not documented in this specification. See <i>The Java Application Programming Interface</i>.)<p>
<a name="20053"></a>
The <code>checkAccept</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if accepting a network connection is to be permitted with a security manager installed.<p>
<a name="14128"></a>
<p><font size=+1><strong>20.17.26   </strong> <code>public void <code><b>checkSetFactory</b></code>()<br>throws SecurityException</code></font>
<p>
<a name="20088"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if installing a "factory" for a socket, server socket, URL, or URL connection is not 
permitted.
<p><a name="20092"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by:<p>
<pre><a name="29846"></a>	method setSocketFactory of class java.net.ServerSocket
<a name="29848"></a>	method setSocketImplFactory of class java.net.Socket
<a name="29849"></a>	method setURLStreamHandlerFactory of class java.net.URL
<a name="29852"></a>	method setContentHandlerFactory of class java.net.URLConnection
</pre><a name="20093"></a>
(These classes are not documented in this specification. See <i>The Java Application 
Programming Interface</i>.)
<p><a name="29916"></a>
The <code>checkSetFactory</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if a factory installation operation is to be permitted with a security manager installed.<p>
<a name="29924"></a>
<p><font size=+1><strong>20.17.27   </strong> <code>public boolean <code><b>checkTopLevelWindow</b></code>()<br>throws SecurityException</code></font>
<p>
<a name="29925"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if creation of a top-level window is not permitted. If creation of a top-level window
is permitted, then this method should return <code>false</code> if the window ought to 
bear a clear warning that it is a window for an executable applet. A returned value 
of <code>true</code> means that the security manager places no restriction on window creation.
<p><a name="29929"></a>
This method is invoked for the current security manager <a href="javalang.doc17.html#3205">(&#167;20.18.4)</a> by the constructors for class <code>java.awt.Window</code>. (This class is not documented in this specification. See <i>The Java Application Programming Interface</i>.)<p>
<a name="29930"></a>
The <code>checkTopLevelWindow</code> method defined by class <code>SecurityManager</code> always returns <code>false</code>. A subclass must override this method if a window creation operation is to be unrestricted or forbidden with a security manager installed.<p>
<a name="36460"></a>
<p><font size=+1><strong>20.17.28   </strong> <code>public void <code><b>checkPackageAccess</b></code>(String packageName)<br>throws SecurityException</code></font>
<p>
<a name="36453"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if the current applet is not permitted to access the package named by the argument.
This method is intended for use by Java-capable web browsers.
<p><a name="36483"></a>
The <code>checkPackageAccess</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if package access by an applet is to be permitted with a security manager installed.<p>
<a name="36488"></a>
<p><font size=+1><strong>20.17.29   </strong> <code>public void <code><b>checkPackageDefinition</b></code>(String packageName)<br>throws SecurityException</code></font>
<p>
<a name="36489"></a>
The general contract of this method is that it should throw a <code>SecurityException</code> 
if the current applet is not permitted to define a class (or interface) in the package 
named by the argument. This method is intended for use by Java-capable web 
browsers.
<p><a name="36490"></a>
The <code>checkPackageAccess</code> method defined by class <code>SecurityManager</code> always throws a <code>SecurityException</code>. A subclass must override this method if class definition by an applet is to be permitted with a security manager installed.<p>


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<font size=-1>Java Language Specification (HTML generated by Suzette Pelouch on February 24, 1998)<br>
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