jfmsocketcore.java

java邮件源程序

/*
 * Created on 2004.08.17
 * JFreeMail - Java mail component
 * Copyright (C) 2004 Dalibor Krleza
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
package org.jfreemail.core;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import java.util.Vector;

/**
 * Class with core methods for socket operation. All methods static.
 */
public class JfmSocketCore {
	/**
	 * Special method for reading multiple text lines from socket. Text lines
	 * are separated on CRLF chars and stored into string array.
	 * @param client_socket Socket with connection to server.
	 * @return String array with incoming information.
	 * @throws IOException Thrown on socket error.
	 */
	public static String[] getLine(Socket client_socket) throws IOException{
		InputStream is=client_socket.getInputStream();
		int length=0,i;
		byte[] in_buffer=new byte[2048];
		Vector result=new Vector();
		String out=new String();
		while(true) {
			/*
			 * Reading buffer from client socket. If reading full buffer, this line
			 * will be called more than once. If reading number of bytes multiple
			 * to buffer size, last buffer length will be 0. On the other hand, on
			 * reading not full buffer, exiting immediately.
			 */
			length=is.read(in_buffer,0,2048);
			for(i=0;i<length;i++) {
				out+=(char)in_buffer[i];
				/*
				 * Testing CRLF. If detected CRLF, store line into vector. We will
				 * create string array later.
				 */
				if (out.length()>=2 && out.charAt(out.length()-1)==(char)10 
					&& out.charAt(out.length()-2)==(char)13) {
						result.add(out);
						out=new String();
					}
			}
			if (length<2048) {
				/*
				 * Now we have readed all info from socket. Creating string
				 * array from vector. I wanted to decrease memory use with
				 * string array.
				 */
				String[] result_list=new String[result.size()];
				for(i=0;i<result.size();i++)
					result_list[i]=(String)result.elementAt(i);
				return result_list;
			}
			length=0;
		}
	}
	
	/**
	 * Special method for reading binary buffer from client socket. This method
	 * is used when unable to detect charset for reading lines.
	 * @param client_socket Client socket with connection to server.
	 * @return Binary array.
	 * @throws IOException Thrown on communication error.
	 */
	public static byte[] getBinary(Socket client_socket) throws IOException{
		InputStream is=client_socket.getInputStream();
		int length=0;
		byte[] in_buffer=new byte[2048];
		/*
		 * We don't know size of readed byte stream. So it's logical to store
		 * this byte array into stream object. For decreasing memory consumption
		 * we will pull out only binary array.
		 */
		ByteArrayOutputStream bos=new ByteArrayOutputStream();
		while(true) {
			length=is.read(in_buffer,0,2048);
			bos.write(in_buffer,0,length);
			if (length<2048) {
				return bos.toByteArray();
			}
			length=0;
		}
	}
}