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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><TITLE>MessageElement (Project JXTA J2SE)</TITLE><META NAME="keywords" CONTENT="net.jxta.endpoint.MessageElement class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="MessageElement (Project JXTA J2SE)";}</SCRIPT></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=3 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/MessageElement.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><a href='http://www.jxta.org' target='_blank'>Project JXTA</a></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../net/jxta/endpoint/Message.ElementIterator.html" title="class in net.jxta.endpoint"><B>PREV CLASS</B></A> <A HREF="../../../net/jxta/endpoint/MessengerEvent.html" title="class in net.jxta.endpoint"><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="MessageElement.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> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <A HREF="#constructor_detail">CONSTR</A> | <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">net.jxta.endpoint</FONT><BR>Class MessageElement</H2><PRE>java.lang.Object <IMG SRC="../../../resources/inherit.gif" ALT="extended by"><B>net.jxta.endpoint.MessageElement</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../../net/jxta/document/Document.html" title="interface in net.jxta.document">Document</A></DD></DL><DL><DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../../net/jxta/endpoint/ByteArrayMessageElement.html" title="class in net.jxta.endpoint">ByteArrayMessageElement</A>, <A HREF="../../../net/jxta/endpoint/InputStreamMessageElement.html" title="class in net.jxta.endpoint">InputStreamMessageElement</A>, <A HREF="../../../net/jxta/impl/endpoint/JxtaMessageMessageElement.html" title="class in net.jxta.impl.endpoint">JxtaMessageMessageElement</A>, <A HREF="../../../net/jxta/endpoint/TextMessageElement.html" title="class in net.jxta.endpoint">TextMessageElement</A></DD></DL><HR><DL><DT>public abstract class <B>MessageElement</B><DT>extends java.lang.Object<DT>implements <A HREF="../../../net/jxta/document/Document.html" title="interface in net.jxta.document">Document</A></DL><P>JXTA Message Elements are used to add data to a Message. Message Elements are immutable objects. A Message Element may be shared amongst as many messages as is desired. A Message Element is composed of four components: <ul> <li>An optional name. This may be any <CODE>String</CODE>. Unnamed elements are assumed to have the name "" (the empty string).</li> <li>An optional <A HREF="../../../net/jxta/document/MimeMediaType.html" title="class in net.jxta.document"><CODE>MimeMediaType</CODE></A>. If not specified the Mime Media Type is assumed to be "Application/Octet-Stream".</li> <li>Data. Sub-classes of MessageElement allow you to create elements based on a variety of data formats.</li> <li>An optional signature. This is a Message Element that is associated to this element and may contain a cryptographic signature/hash of this message element. </li> <p/>The data contained with in a MessageElement is accessible in four ways: <ul> <li>As an <CODE>InputStream</CODE></li> <li>Sending the data a <CODE>OutputStream</CODE></li> <li>As a <CODE>String</CODE>.</li> <li>As a byte array.</li> </ul><P><P><DL><DT><B>See Also:</B><DD><A HREF="../../../net/jxta/endpoint/Message.html" title="class in net.jxta.endpoint"><CODE>Message</CODE></A></DL><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><A NAME="field_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Field Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected long</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#cachedGetByteLength">cachedGetByteLength</A></B></CODE><BR> cached result of <A HREF="../../../net/jxta/endpoint/MessageElement.html#getByteLength()"><CODE>getByteLength()</CODE></A> operation.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.lang.ref.SoftReference</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#cachedGetBytes">cachedGetBytes</A></B></CODE><BR> cached result of <A HREF="../../../net/jxta/endpoint/MessageElement.html#getBytes(boolean)"><CODE>getBytes(boolean)</CODE></A> operation.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.lang.ref.SoftReference</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#cachedToString">cachedToString</A></B></CODE><BR> cached result of <A HREF="../../../net/jxta/endpoint/MessageElement.html#toString()"><CODE>toString()</CODE></A> operation.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#name">name</A></B></CODE><BR> The name of this element. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.util.Map</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#properties">properties</A></B></CODE><BR> message properties hashmap</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected <A HREF="../../../net/jxta/endpoint/MessageElement.html" title="class in net.jxta.endpoint">MessageElement</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#sig">sig</A></B></CODE><BR> The optional element which digitially signs or digests this element. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected <A HREF="../../../net/jxta/document/MimeMediaType.html" title="class in net.jxta.document">MimeMediaType</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#type">type</A></B></CODE><BR> The type of this element.</TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected </CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#MessageElement()">MessageElement</A></B>()</CODE><BR> disabled</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected </CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#MessageElement(java.lang.String, net.jxta.document.MimeMediaType, net.jxta.endpoint.MessageElement)">MessageElement</A></B>(java.lang.String name, <A HREF="../../../net/jxta/document/MimeMediaType.html" title="class in net.jxta.document">MimeMediaType</A> type, <A HREF="../../../net/jxta/endpoint/MessageElement.html" title="class in net.jxta.endpoint">MessageElement</A> sig)</CODE><BR> Internal constructor for initializaing everything but the data.</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"><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> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#clone()">clone</A></B>()</CODE><BR> Make a clone of this element. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected static void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#copyInputStreamToOutputStream(java.io.InputStream, java.io.OutputStream)">copyInputStreamToOutputStream</A></B>(java.io.InputStream source, java.io.OutputStream sink)</CODE><BR> Copies an input stream to an output stream with buffering.</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="../../../net/jxta/endpoint/MessageElement.html#equals(java.lang.Object)">equals</A></B>(java.lang.Object target)</CODE><BR> <p/>Elements are considered equal if they have the same name, type and signatures. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> long</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getByteLength()">getByteLength</A></B>()</CODE><BR> Returns the size of the element data in bytes.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> byte[]</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getBytes(boolean)">getBytes</A></B>(boolean copy)</CODE><BR> Returns a byte array which contains the element data. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getElementName()">getElementName</A></B>()</CODE><BR> Returns the name of the MessageElement. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getElementProperty(java.lang.Object)">getElementProperty</A></B>(java.lang.Object key)</CODE><BR> retrieves a transient property from the set for this element.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getFileExtension()">getFileExtension</A></B>()</CODE><BR> Returns the file extension type used by this <code>Document</code>. This value is usually chosen based upon the MIME Media Type. <p/>We use the "unknown" extension and leave it to sub-classes to extend this. </TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../../net/jxta/document/MimeMediaType.html" title="class in net.jxta.document">MimeMediaType</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../../net/jxta/endpoint/MessageElement.html#getMimeType()">getMimeType</A></B>()</CODE><BR>⌨️ 快捷键说明
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