
package org.jgroups.conf;

import org.jgroups.JChannel;
import org.jgroups.util.Util;
import org.w3c.dom.Element;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.AccessControlException;
import java.util.List;
import java.util.Map;

/**
 * The ConfigurationFactory is a factory that returns a protocol stack configurator.
 * The protocol stack configurator is an object that read a stack configuration and
 * parses it so that the ProtocolStack can create a stack.
 * <BR>
 * Currently the factory returns one of the following objects:<BR>
 * 1. XmlConfigurator - parses XML files<BR>
 * 2. PlainConfigurator - uses the old style strings UDP:FRAG: etc etc<BR>
 *
 * @author Filip Hanik (<a href="mailto:filip@filip.net">filip@filip.net)
 * @author Bela Ban
 */
public class ConfiguratorFactory {
    public static final String JAXP_MISSING_ERROR_MSG="the required XML parsing classes are not available; " +
      "make sure that JAXP compatible libraries are in the classpath.";


    protected ConfiguratorFactory() {
    }

    /**
     * Returns a protocol stack configurator based on the XML configuration provided by the specified File.
     * 
     * @param file a File with a JGroups XML configuration.
     * @return a <code>ProtocolStackConfigurator</code> containing the stack configuration.
     * @throws Exception if problems occur during the configuration of the protocol stack.
     */
    public static ProtocolStackConfigurator getStackConfigurator(File file) throws Exception {
        checkJAXPAvailability();
        InputStream input=getConfigStream(file);
        return XmlConfigurator.getInstance(input);
    }

    public static ProtocolStackConfigurator getStackConfigurator(InputStream input) throws Exception {
        return XmlConfigurator.getInstance(input);
    }

    /**
     * Returns a protocol stack configurator based on the XML configuration provided at the specified URL.
     *
     * @param url a URL pointing to a JGroups XML configuration.
     * @return a <code>ProtocolStackConfigurator</code> containing the stack configuration.
     * @throws Exception if problems occur during the configuration of the protocol stack.
     */
    public static ProtocolStackConfigurator getStackConfigurator(URL url) throws Exception {
        checkForNullConfiguration(url);
        checkJAXPAvailability();
        return XmlConfigurator.getInstance(url);
    }

    /**
     * Returns a protocol stack configurator based on the XML configuration provided by the specified XML element.
     *
     * @param element a XML element containing a JGroups XML configuration.
     * @return a <code>ProtocolStackConfigurator</code> containing the stack configuration.
     * @throws Exception if problems occur during the configuration of the protocol stack.
     */
    public static ProtocolStackConfigurator getStackConfigurator(Element element) throws Exception {
        checkForNullConfiguration(element);
        return XmlConfigurator.getInstance(element);
    }

    /**
     * Returns a protocol stack configurator based on the provided properties string.
     *
     * @param properties an old style property string, a string representing a system resource containing a JGroups
     *                   XML configuration, a string representing a URL pointing to a JGroups XML configuration,
     *                   or a string representing a file name that contains a JGroups XML configuration.
     */
    public static ProtocolStackConfigurator getStackConfigurator(String properties) throws Exception {
        // added by bela: for null String props we use the default properties
        if(properties == null)
            properties=JChannel.DEFAULT_PROTOCOL_STACK;

        // Attempt to treat the properties string as a pointer to an XML configuration.
        XmlConfigurator configurator = null;

        checkForNullConfiguration(properties);
        configurator=getXmlConfigurator(properties);

        if (configurator != null) // did the properties string point to a JGroups XML configuration ?
            return configurator;
        else
            return new PlainConfigurator(properties); // try to process the properties string as an old style property string
    }



    public static InputStream getConfigStream(File file) throws Exception {
        checkForNullConfiguration(file);
        return new FileInputStream(file);
    }



    public static InputStream getConfigStream(URL url) throws Exception {
        checkJAXPAvailability();
        return url.openStream();
    }



    /**
     * Returns a JGroups XML configuration InputStream based on the provided properties string.
     *
     * @param properties a string representing a system resource containing a JGroups XML configuration, a string
     *                   representing a URL pointing to a JGroups ML configuration, or a string representing
     *                   a file name that contains a JGroups XML configuration.
     * @throws IOException  if the provided properties string appears to be a valid URL but is unreachable.
     */
    public static InputStream getConfigStream(String properties) throws IOException {
        InputStream configStream = null;

        // Check to see if the properties string is the name of a file.
        try {
            configStream=new FileInputStream(properties);
        }
        catch(FileNotFoundException fnfe) {
            // the properties string is likely not a file
        }
        catch(AccessControlException access_ex) {
            // fixes http://jira.jboss.com/jira/browse/JGRP-94
        }

        // Check to see if the properties string is a URL.
        if(configStream == null) {
            try {
                configStream=new URL(properties).openStream();
            }
            catch (MalformedURLException mre) {
                // the properties string is not a URL
            }
        }

        // Check to see if the properties string is the name of a resource, e.g. udp.xml.
        if(configStream == null && properties.endsWith("xml"))
            configStream=Util.getResourceAsStream(properties, ConfiguratorFactory.class);
        return configStream;
    }


    public static InputStream getConfigStream(Object properties) throws IOException {
        InputStream input=null;

        // added by bela: for null String props we use the default properties
        if(properties == null)
            properties=JChannel.DEFAULT_PROTOCOL_STACK;

        if(properties instanceof URL) {
            try {
                input=((URL)properties).openStream();
            }
            catch(Throwable t) {
            }
        }

        // if it is a string, then it could be a plain string or a url
        if(input == null && properties instanceof String)
            input=getConfigStream((String)properties);

        // try a regular file
        if(input == null && properties instanceof File) {
            try {
                input=new FileInputStream((File)properties);
            }
            catch(Throwable t) {
            }
        }

        if(input != null)
            return input;

        if(properties instanceof Element) {
            return getConfigStream(properties);
        }

        return new ByteArrayInputStream(((String)properties).getBytes());
    }




    /**
     * Returns an XmlConfigurator based on the provided properties string (if possible).
     *
     * @param properties a string representing a system resource containing a JGroups XML configuration, a string
     *                   representing a URL pointing to a JGroups ML configuration, or a string representing a file
     *                   name that contains a JGroups XML configuration.
     * @return an XmlConfigurator instance based on the provided properties string; <code>null</code> if the provided
     *         properties string does not point to an XML configuration.
     * @throws IOException  if the provided properties string appears to be a valid URL but is unreachable, or if the
     *                      JGroups XML configuration pointed to by the URL can not be parsed.
     */
    static XmlConfigurator getXmlConfigurator(String properties) throws IOException {
        XmlConfigurator returnValue=null;
        InputStream configStream=getConfigStream(properties);
        if(configStream == null && properties.endsWith(".xml"))
            throw new FileNotFoundException(String.format(Util.getMessage("FileNotFound"), properties));

        if (configStream != null) {
            checkJAXPAvailability();
            returnValue=XmlConfigurator.getInstance(configStream);
        }

        return returnValue;
    }


    /**
     * Check to see if the specified configuration properties are <code>null</null> which is not allowed.
     * @param properties the specified protocol stack configuration.
     * @throws NullPointerException if the specified configuration properties are <code>null</code>.
     */
    static void checkForNullConfiguration(Object properties) {
        if(properties == null)
            throw new NullPointerException("the specifed protocol stack configuration was null");
    }

    /**
     * Checks the availability of the JAXP classes on the classpath.
     * @throws NoClassDefFoundError if the required JAXP classes are not availabile on the classpath.
     */
    static void checkJAXPAvailability() {
        try {
            XmlConfigurator.class.getName();
        }
        catch (NoClassDefFoundError error) {
            Error tmp=new NoClassDefFoundError(JAXP_MISSING_ERROR_MSG);
            tmp.initCause(error);
            throw tmp;
        }
    }

    /**
     * Replace variables of the form ${var:default} with the getProperty(var,
     * default)
     * 
     * @param configurator
     */
    public static void substituteVariables(ProtocolStackConfigurator configurator) {
        List<ProtocolConfiguration> protocols=configurator.getProtocolStack();
        for(ProtocolConfiguration data: protocols) {
            if(data != null) {
                Map<String,String> parms=data.getProperties();
                for(Map.Entry<String,String> entry:parms.entrySet()) {
                    String val=entry.getValue();
                    String replacement=Util.substituteVariable(val);
                    if(!replacement.equals(val)) {
                        entry.setValue(replacement);
                    }
                }
            }
        }
    }          
}









