butorconfig.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.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.butor.config.IConfig;
import org.butor.helper.Message;
import org.butor.log.Log;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

/**
 * @version 	1.0
 * @author
 */
public class ButorConfig extends PropertyContainer
	implements IConfigLoader, IConfig {

	/**
	 * config property key to retreive the application name of the config.
	 */
	public static final String PROPERTY_APP_NAME = "app_name";

	protected List f_errors = new ArrayList();

	protected String f_confFilenameAndPath = null;
	protected String f_filename = null;
	protected String[] f_suffixes = null;

	/**
	 * Constructor for Config.
	 */
	public ButorConfig(ButorConfig parent) {
		super();
		
		f_confDir = parent.getConfDir();
		f_appDir  = parent.getAppDir();
		f_logDir  = parent.getLogDir();
		f_repositoryConfDir = parent.getRepositoryConfDir();
	}
	/**
	 * Constructor for Config.
	 */
	public ButorConfig(String confFilenameAndPath) throws IOException {
		this(confFilenameAndPath, null, null, null,null);
	}
	/**
	 * Constructor for Config.
	 */
	public ButorConfig(
		String confFilenameAndPath,
		String appDir,
		String repositoryConfDir,
		String logDir,
		String[] suffixes)
		throws IOException {
			
		super();
		
		f_confFilenameAndPath = confFilenameAndPath;
		f_appDir = appDir;
		f_logDir = logDir;
		
		if (repositoryConfDir != null) {
			f_repositoryConfDir = repositoryConfDir +
				(repositoryConfDir.endsWith(File.separator) ? "" : File.separator);
		}
		
		f_suffixes = suffixes;

		if (f_confFilenameAndPath == null) {
			Log.logStr(this, Log.LOG_TYPE_WARN, "ButorConfig", 
				"Got NULL config file name and path!");
			return;
		}
		
		// We must extract the config dir
		File file = new File(confFilenameAndPath);		
		f_confDir =	file.getParent();
		f_filename = file.getName();

		loadOneConfigFile(this, f_filename, true);
		
		mergeExternalConfigs();
		
		if (Log.shouldLog(this.getClass().getName(), Log.LOG_LEVEL_LOW)) {			
			Log.logStr(this, Log.LOG_TYPE_INFO, "ButorConfig", 
				"loaded the following config:" +this.toString());
		}
	}
	/**
	 * 
	 */
	public String getConfigFilename() {
		return f_confFilenameAndPath;
	}
	/**
	 * Add a property list
	 * 
	 * @param list PropertyList, property list
	 */
	public void addPropertyList(PropertyList list) {
		if (list == null) {
			Log.logStr(
				this,
				Log.LOG_TYPE_WARN,
				"addPropertyList()",
				"Got NULL list!");
			return;
		}

		list.setAppDir(f_appDir);
		list.setConfDir(f_confDir);
		list.setRepositoryConfDir(f_repositoryConfDir);
		list.setLogDir(f_logDir);

		addProperty(list.getName(), list);
	}
	/**
	 * remove a property list element.
	 *
	 * @param name String, Property list name
	 */
	protected void removePropertyList(String name) {
		Object value = getProperty(name);
		if (value instanceof IProperties) {
			removeProperty(value);
		}
	}
	/**
	* toString this object content.
	* 
	* @return String.
	*/
	public String toString() {
		StringBuffer buffer =
			new StringBuffer("\n==================== BEGIN OF CONFIG ======================\n");

		buffer.append(super.toString());

		buffer.append("\n\n");

		buffer.append(getProperties().toString());

		buffer.append(
			"\n==================== END OF CONFIG ======================\n");

		return buffer.toString();
	}
	/**
	 * Append Config to this one.
	 * Existing properties will be overriden.
	 * 
	 * @param config IConfig.
	 */
	protected synchronized void merge(IConfigLoader configToAppend) {
		synchronized (configToAppend) {
			if (configToAppend == null) {
				return;
			}

			// errors
			if (configToAppend.isErrorsOccured()) {
				List errors = configToAppend.getOccuredErrors();
				f_errors.addAll(errors);
			}

			// Append properties
			Iterator it = configToAppend.getProperties().iterator();
			Property newP;
			while (it.hasNext()) {
				newP = (Property) it.next();

				Object oldVal =
					this.getProperty((String) newP.getKey());
				if (oldVal != null) {
					Log.logStr(
						this,
						Log.LOG_TYPE_INFO,
						"merge()",
						"Overriding property, key=["
							+ newP.getKey()
							+ "], oldValue=["
							+ oldVal
							+ "], newValue=["
							+ newP.getValue()
							+ "]");


					if (oldVal instanceof PropertyList) {
						((PropertyList)newP.getValue()).setConfDir(((PropertyList)oldVal).getConfDir());
						((PropertyList)newP.getValue()).setAppDir(((PropertyList)oldVal).getAppDir());
						((PropertyList)newP.getValue()).setLogDir(((PropertyList)oldVal).getLogDir());
						((PropertyList)newP.getValue()).setRepositoryConfDir(((PropertyList)oldVal).getRepositoryConfDir());
					}
					this.removeProperty(newP.getKey());
				}
				addProperty(newP.getKey(), newP.getValue());
			}
		}
	}
	/**
	 * Find and return the filename and its path
	 * 1) Check if the file exists in the external config directory.
	 * 2) Check if the file exists in the application config directory.
	 */
	protected String findFile(String filename) {

		String filenameAndPath = null;
		File file = null;
		
		if (f_repositoryConfDir != null) {
			filenameAndPath = f_repositoryConfDir +filename;

			Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "findFile()", 
				"Looking for file [" +filenameAndPath +"] ...");

			file = new File(filenameAndPath);
			if (file.exists() && file.isFile()) {
				return filenameAndPath;
			}
		}
		
		if (f_confDir != null) {
			filenameAndPath = f_confDir +File.separator +filename;

			Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "findFile()", 
				"Looking for file [" +filenameAndPath +"] ...");

			file = new File(filenameAndPath);
			if (file.exists() && file.isFile()) {
				return filenameAndPath;
			}
		}
		
		return null;
	}
	/**
	 * Load configuration file. get the file from
	 * the external config directory if exists. If not try
	 * the application config directory.
	 */
	protected void loadOneConfigFile(
		IConfigLoader config,
		String filename,
		boolean validateXml)
		throws IOException {

		String filenameAndPath = findFile(filename);
		if (filenameAndPath == null) {
			Log.logStr(
				Log.LOG_LEVEL_LOW,
				this,
				Log.LOG_TYPE_INFO,
				"loadOneConfigFile()",
				"Config file not found [" + filename + "]");
			return;
		}
		
		Log.logStr(
			this,
			Log.LOG_TYPE_INFO,
			"loadOneConfigFile()",
			"Found and Loading config file [" + filenameAndPath + "]");

		try {
			SaxErrorHandler errorHandler = new SaxErrorHandler();
			XMLReader parser = XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser");
			parser.setErrorHandler(errorHandler);
			ConfigParseHandler handler = new ConfigParseHandler(config);
			parser.setContentHandler(handler);
			parser.setEntityResolver(new ButorConfigEntityResolver());
			parser.parse(filenameAndPath);
			config.setOccuredErrors(errorHandler.getErrorList());
			
		} catch (SAXException e) {
			Log.logException(this, Log.LOG_TYPE_ERROR, "loadOneConfigFile()", e);
			throw new IOException(e.getMessage());
		}
	}
	/**
	 * 
	 */
	protected void mergeExternalConfigs() {

		if (f_suffixes == null) {
			return;
		}

		/*
		 * Configs to override default properties.
		 * prepare environment path and files name & prefixes.
		 */
		IConfigLoader config = null;
		String envFile = null;

		/*
		 * for each suffixe in the list, if a file have the config file name
		 * and end with the prefix then load it to override/add special properties.
		 * order of the list is important.
		 */
		for (int i = 0; i < f_suffixes.length; i++) {
			if (f_suffixes[i] == null) {
				continue;
			}

			envFile = f_filename + "." + f_suffixes[i];

			Log.logStr(
				this,
				Log.LOG_TYPE_INFO,
				"mergeSpecificConfigs()",
				"Merging config file [" + envFile + "]");

			config = new ButorConfig(this);
			boolean retryWithoutXmlValidation = false;
				try {
				loadOneConfigFile(config, envFile, true);
				
				if (config != null) {
					merge(config);
				}

			} catch (IOException e) {
				Log.logStr(
					this,
					Log.LOG_TYPE_ERROR,
					"mergeSpecificConfigs()",
					e.getMessage()
						+ " Will try to load without validating XML ...");

				Message error = new Message();
				error.setSeverity(Message.SEVERITY_ERROR);
				error.setText(e.getMessage());
				f_errors.add(error);

				retryWithoutXmlValidation = true;

			}

			if (retryWithoutXmlValidation) {
				try {
					loadOneConfigFile(config, envFile, false);
					merge(config);

				} catch (IOException e) {
					Log.logException(
						this,
						Log.LOG_TYPE_ERROR,
						"mergeSpecificConfigs()",
						e);
				}
			}
		}
	}
	/**
	 * 
	 */
	public boolean isErrorsOccured() {
		return (f_errors != null && f_errors.size() > 0);
	}
	/**
	 * 
	 */
	public List getOccuredErrors() {
		return f_errors;
	}
	/**
	 * 
	 */
	public void setOccuredErrors(List errors) {
		f_errors = errors;
	}
	/**
	 * @see org.butor.wak.config.lowlevel.IProperties#getName()
	 */
	public String getName() {
		// Name at this level has no meaning.
		return null;
	}

	/**
	 * Get the application name
	 */
	public String getAppName() {
		return System.getProperty(PROPERTY_APP_NAME, getProperty(PROPERTY_APP_NAME, null));
	}

}