configparsehandler.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.config.lowlevel;

import java.util.Stack;

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;

/**
 * @author sawanai
 *
 * This is a first working handler for Butor Config.
 */
public class ConfigParseHandler implements ContentHandler {
	protected Stack f_configList = null;
	protected IConfigLoader config = null;
	/**
	 * 
	 */
	public ConfigParseHandler(IConfigLoader config) {
		super();
		this.config = config;
		f_configList = new Stack();
		f_configList.push(config);
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#setDocumentLocator(org.xml.sax.Locator)
	 */
	public void setDocumentLocator(Locator locator) {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#startDocument()
	 */
	public void startDocument() throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#endDocument()
	 */
	public void endDocument() throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#startPrefixMapping(java.lang.String, java.lang.String)
	 */
	public void startPrefixMapping(String prefix, String uri)
		throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#endPrefixMapping(java.lang.String)
	 */
	public void endPrefixMapping(String prefix) throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
	 */
	public void startElement(
		String namespaceURI,
		String localName,
		String qName,
		Attributes atts)
		throws SAXException {

		if (localName.equalsIgnoreCase("list")) {
			PropertyList list = new PropertyList();
			list.setName(checkValue(atts.getValue("name")));
			
			/*
			 * No need to check depth!  The only way the
			 * stack could be empty and we are beginning
			 * a "list" element is if the XML document is
			 * not well-formed, which is impossible because
			 * the XML parser would have already barfed...
			 */
			PropertyContainer parent = (PropertyContainer)f_configList.peek();
			list.setConfDir(parent.getConfDir());
			list.setAppDir(parent.getAppDir());
			list.setRepositoryConfDir(parent.getRepositoryConfDir());
			list.setLogDir(parent.getLogDir());
			parent.addProperty(list.getName(), list);
			
			// This list is becoming the "parent" of
			// any next list until we close it...
			f_configList.push(list);
			
		} else if (localName.equalsIgnoreCase("item")) {
			// No problem possible with stack depth, see above
			PropertyContainer parent = (PropertyContainer)f_configList.peek();
			parent.addProperty(checkValue(atts.getValue("name")), checkValue(atts.getValue("value")));

		} else if (localName.equalsIgnoreCase("property")) {
			// No problem possible with stack depth, see above
			PropertyContainer parent = (PropertyContainer)f_configList.peek();
			parent.addProperty(checkValue(atts.getValue("name")), checkValue(atts.getValue("value")));
		}
	}

	protected String checkValue(String value) {
		if (value == null) {
			return value;
		}
		
		int spos = value.indexOf("${");
		while (spos > -1) {
			int epos = value.indexOf("}", spos);
			if (epos == -1) {
				break;
			}
			// check first for the macros app_dir et conf_dir. They are defined
			// in this config object
			String var = value.substring(spos, epos+1);
			PropertyContainer parent = (PropertyContainer)f_configList.peek();
			if (var.equalsIgnoreCase(PropertyContainer.MACRO_APP_DIR)) {
				var = parent.getAppDir();
			} else 	if (var.equalsIgnoreCase(PropertyContainer.MACRO_CONF_DIR)) {
				var = parent.getConfDir();
			} else 	if (var.equalsIgnoreCase(PropertyContainer.MACRO_LOG_DIR)) {
				var = parent.getLogDir();
			} else 	if (var.equalsIgnoreCase(PropertyContainer.MACRO_REPOSITORY_CONF_DIR)) {
				var = parent.getRepositoryConfDir();
			} else {
				// check then as system variables
				var = value.substring(spos+2, epos);
				var = System.getProperty(var);
			}
			if (var != null) {
				value = value.substring(0, spos) +var +value.substring(epos+1);
			}
			spos = value.indexOf("${", epos);
		}
		return value;
	}
	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
	 */
	public void endElement(String namespaceURI, String localName, String qName)
		throws SAXException {
		if (localName.equalsIgnoreCase("list")) {
			/*
			 * No need to check depth!  The only way the
			 * stack could be empty and we are ending
			 * a "list" element is if the XML document is
			 * not well-formed, which is impossible because
			 * the XML parser would have already barfed...
			 */
			f_configList.pop();
		}
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#characters(char[], int, int)
	 */
	public void characters(char[] ch, int start, int length)
		throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#ignorableWhitespace(char[], int, int)
	 */
	public void ignorableWhitespace(char[] ch, int start, int length)
		throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#processingInstruction(java.lang.String, java.lang.String)
	 */
	public void processingInstruction(String target, String data)
		throws SAXException {
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#skippedEntity(java.lang.String)
	 */
	public void skippedEntity(String name) throws SAXException {
	}
}