MimeHeader.java

package com.sun.ejte.ccl.webrunner.proxy;

import java.util.*;

/**
* MIME is an internet standard for communicating multimedia content over e-mail systems.MimeHeader extends HashTable so that it can store key value pairs.
* @author       Deepa Singh(deepa.singh@sun.com)
 *Company: Sun Microsystems Inc
* 
*/
public class MimeHeader extends Hashtable
{
	/**
	* Takes a String as a parameter and parses it.Takes a raw MIME-formatted String and enter its key/value pairs into a given instance of MimeHeader.Uses
         *StringTokenizer to split the input data into individual lines marked by CRLF(\r\n) sequence.
	* @author       Deepa Singh(deepa.singh@sun.com)
	* @return       void
	* @param		data	The string to be parsed
	*/
	void parse(String data)
	{
	StringTokenizer st=new StringTokenizer(data,"\r\n");
		while(st.hasMoreTokens())
		{
			String s=st.nextToken();
			int colon=s.indexOf(':');
			String key=s.substring(0,colon);
			String val=s.substring(colon+2);
			put(key,val);
		}
	}
	
	/**
	* Default Constructor 
         *Class is a subclass of HashTable so that it can conveneintly store and retreive the key/value pairs
         *associated with a MIME header.It creates a blank MimeHeader with no keys.
	* @author       Deepa Singh(deepa.singh@sun.com)
	* 
	* @param		None
	*/
	MimeHeader(){}
	
	/**
	* This constructor takes strng formatted as MIME header and parses it for the initial contents of the objects.
	* @author       Deepa Singh(deepa.singh@sun.com)
	* 
	* @param		d	The string to be parsed
	*/
	MimeHeader(String d)
	{
		parse(d);
	}
	
	/**
	* Converts to String .It takes current key/value pairs stored in the MimeHeader and returns a string representation of them in
         *MIME format, where keys are printed followed by colon and a space, and then value followed by CRLF.
	* @author       Deepa Singh(deepa.singh@sun.com)
	* @return       String
	*/
	public String toString()
	{
		String ret="";
		Enumeration e=keys();
		while(e.hasMoreElements())
		{
		String key=(String)e.nextElement();
		String val=(String)get(key);
		ret+=key + ": " + val + "\r\n";
		}
	return ret;
	}

	/**
	*To remove the discrepancy in MIME specification for "Content-Type" and "content-type" and "Content-Length" to "content-length"
         *To avoid problems, all incoming and outgoing MimeHeader keys are converted to canonical form. 
	* @author       Deepa Singh(deepa.singh@sun.com)
	* @return       String
	* @param		ms	String to be operated upon
	*/
	private String fix(String ms)
	{
		char chars[]=ms.toLowerCase().toCharArray();
		boolean upcaseNext=true;
		for(int i=0;i<chars.length-1;i++)
		{
			char ch=chars[i];
			if(upcaseNext && 'a' <=ch && ch <='z')
			{
				chars[i]=(char)(ch-('a'-'A'));
			}
			upcaseNext=ch=='-';
		}
	return new String(chars);
	}

	/**
	* @author       Deepa Singh(deepa.singh@sun.com)
	* @return       String
	* @param		key	String to be fetched	
	*/
	public String get(String key)
	{
		return (String)super.get(fix(key));
	}

	/**
	*  
	* @author       Deepa Singh(deepa.singh@sun.com)
	* @return       void
	* @param		key		The Key String	
	* @param		val  	The value String	
	*/
	public void put(String key,String val)
	{
		super.put(fix(key),val);
	}
	
	
}