xmlinput.java

来自「用Java开发的、实现类似Visio功能的应用程序源码」· Java 代码 · 共 217 行

/**
 *    $Id:XMLInput.java $
 *
 *    Copyright 2004 ~ 2005  JingFei International Cooperation LTD. All rights reserved. *
 */
package com.jfimagine.jfdom;


import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.FileInputStream;
import java.net.URL;
import com.jfimagine.utils.commonutil.CommonUtil;

import com.jfimagine.utils.log.*;
 
 /**
 * XMLInput class.  A class used to input an XML document.
 *
 * @author     CookieMaker    
 *
 * @version $Revision: 1.01 $
 */  
 public class XMLInput{
	
	//a text content got from a text file        
        private String m_content="";
        //current reading position on the text content.
	private int m_pos=0;        
	
	/**an internal log utility*/
	private JFLogger m_logger	=JFLogManager.getLogger(this.getClass());
        
        /**
         *   Read text content from a text file.
         *   @param fileName name of the text file.
         *   @return text content of a text file.
         */
	public void readTextFile(String fileName){
		StringBuffer buf	=new StringBuffer();		
		try{
			InputStream in=null;
			
			if (CommonUtil.isURLFile(fileName)){
				URL url	=new URL(fileName);
				in	=url.openStream();
				url	=null;

			}else{
          			in=new FileInputStream(fileName);

            		}
				                	
					BufferedReader reader = new BufferedReader(new InputStreamReader(in));
                	while (true){
                		String text	= reader.readLine();
                		if (text==null)
                			break;
                		buf.append(text);
                	}
                	reader.close();
                	in.close();
                	
                	reader		=null;
                	in		=null;

    			m_content	=new String(buf.toString());
    			buf.setLength(0);
    			buf=null;

                }catch(Exception e){
                	m_logger.error("read text file: "+e);
                	m_content	=null;
                }
        }


        /**
         *   load document from xml file.
         *   @param fileName an xml file name
         *   @return An XML Document contains the xml content.
         */
	public Document loadDocument(String fileName){ 
		if (fileName==null || fileName.length()==0)
			return null;
			
		readTextFile(fileName);
		return loadDocumentFromText();
	}

        /**
         *   load document from xml text.
         *   @param xml Plain xml text.
         *   @return An XML Document contains the xml content.
         */
	public Document loadDocumentFromText(String xml){ 
		m_content	=xml;
		return loadDocumentFromText();
	}

        /**
         *   load document from local xml text content.
         *   @return An XML Document contains the xml content.
         */
	private Document loadDocumentFromText(){ 
		if (m_content==null || m_content.length()==0)
			return null;
		
		m_pos		=0;
		
		//remove xml head.
 		int headEnd	=m_content.indexOf("?>");
 		if (headEnd<0)
 			return null;
		m_pos	=headEnd+2;		
		
                Element root	=getElement(); 
		//clear content		
		m_content="";

		if (root!=null)
			return new Document(root);
		else
			return null;
	}

	
        /**
         *   Get element from current text content and pos.
         */
	private Element getElement(){
		if (m_pos>m_content.length()-1)
			return null;
		
		boolean tagStart	=false;
		boolean tagEnd		=false;
		StringBuffer buf	=new StringBuffer();
		
		while (m_pos<m_content.length()){
			char ch	=m_content.charAt(m_pos);
			if (!tagStart){
				if (ch==XMLConst.XML_STARTTAG)
					tagStart	=true;
			}else if (!tagEnd){
				if (ch==XMLConst.XML_ENDTAG){
					tagEnd		=true;
				}else{
					buf.append(ch);
				}
			}
			m_pos++;
			if (tagEnd){
				Element	  element= new Element();
				element.setTag(buf.toString());
				fetchElements(element); 
				return element;
			}
		} 
		
		return null;
	}
	
        /**
         *   Fetch sub elements from current text content and pos.
	 *   @param element An element to add sub elements.         
         */
	private void fetchElements(Element element){
		String tag=element.getTag();
		StringBuffer buf=new StringBuffer();
		boolean hasChildren=false;
		buf.append("");

		while (m_pos<m_content.length()){
			char ch	=m_content.charAt(m_pos);
			if (ch==XMLConst.XML_STARTTAG){
				if (m_content.indexOf(XMLConst.XML_ENDSTARTTAG+tag,m_pos)==m_pos){
				//found the end of this element:
					if (!hasChildren){
						element.setValue(buf.toString().trim());
					}
					int tagEnd	=m_content.indexOf(XMLConst.XML_ENDTAG,m_pos);
					if (tagEnd<0)
						//broken xml
						m_pos	=m_content.length();						
					else
					    	m_pos	=tagEnd+1;
					return;
				
				}else{
				//spawn new sub element:
					hasChildren		=true;
					Element subElement	=getElement();
					if (subElement!=null)
						element.addChild(subElement);
				}
			}else if (ch==XMLConst.XML_ENDTAG){ 
				//invalid tag.
				m_pos	=m_content.length();
				return;
			}else {
				if (!hasChildren)
					buf.append(ch);
			}
			
			m_pos++;
		}
	}



	
        
        

}