org.jboss.ejb3.locator.client.JndiHostConfigurationParser.java Source code

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Here is the source code for org.jboss.ejb3.locator.client.JndiHostConfigurationParser.java

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/*
  * JBoss, Home of Professional Open Source
  * Copyright 2007, JBoss Inc., and individual contributors as indicated
  * by the @authors tag. See the copyright.txt in the distribution for a
  * full listing of individual contributors.
  *
  * This is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * This software is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this software; if not, write to the Free
  * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
  */
package org.jboss.ejb3.locator.client;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.digester.Digester;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.validator.GenericValidator;
import org.xml.sax.SAXException;

public class JndiHostConfigurationParser {

    // Class Members
    private static final Log logger = LogFactory.getLog(JndiHostConfigurationParser.class);

    private static JndiHostConfigurationParser instance = null;

    public static final String DEFAULT_JNDI_HOST_ID_PREFIX = "JNDIHOST-";

    // Internal Constructor
    private JndiHostConfigurationParser() {

    }

    // Singleton Accessor
    public static synchronized JndiHostConfigurationParser getInstance() {
        // Ensure instanciated
        if (JndiHostConfigurationParser.instance == null) {
            JndiHostConfigurationParser.instance = new JndiHostConfigurationParser();
        }

        // Return
        return JndiHostConfigurationParser.instance;
    }

    // Functional Methods

    @SuppressWarnings(value = "unchecked")
    public Map<String, JndiHost> parse(InputStream inStream) {
        // Initialize
        Digester jndiHostDefinitionsDigester = new Digester();
        // Add Rules for parsing configuration
        this.addJndiHostDefinitionsParsingRules(jndiHostDefinitionsDigester);

        // Parse
        List<JndiHost> jndiHosts = null;
        try {
            // Parse
            jndiHosts = (List<JndiHost>) jndiHostDefinitionsDigester.parse(inStream);
        } catch (IOException e) {
            throw new ServiceLocatorException(e);
        } catch (SAXException e) {
            throw new ServiceLocatorException(e);
        }

        // Assign each JNDI Host a unique ID, if not assigned
        int id = 0;
        List<String> ids = new ArrayList<String>();
        for (JndiHost jndiHost : jndiHosts) {
            // No ID specified for this host, assign one
            if (GenericValidator.isBlankOrNull(jndiHost.getId())) {
                jndiHost.setId(JndiHostConfigurationParser.DEFAULT_JNDI_HOST_ID_PREFIX + Integer.toString((id++)));
            }

            // Check for multiple IDs
            if (ids.contains(jndiHost.getId())) {
                throw new ServiceLocatorException("JNDI Host with address " + jndiHost.getAddress()
                        + " has conflicting/duplicate ID of " + jndiHost.getId());
            } else {
                // Add to list of IDs
                ids.add(jndiHost.getId());
            }
        }

        // Add to Map, indexed by ID
        Map<String, JndiHost> hosts = new HashMap<String, JndiHost>();
        for (JndiHost host : jndiHosts) {
            hosts.put(host.getId(), host);
        }

        // Return Map
        return hosts;
    }

    // Internal Helper Methods

    /**
     * Adds parsing rules for reading configuration specifying JNDI Hosts
     * 
     * @param digester
     */
    private void addJndiHostDefinitionsParsingRules(Digester digester) {

        // When the root is encountered, create a List
        // to hold the JNP Host Definitions
        digester.addObjectCreate("service-locator/jndi-hosts", ArrayList.class);

        // When a new host definition is encountered,
        // create a new JNP Host
        digester.addObjectCreate("service-locator/jndi-hosts/jndi-host", JndiHost.class);

        // Set all properties (in this case, "name")
        // from the "host" entry to the "JnpHost.name"
        // object
        digester.addSetProperties("service-locator/jndi-hosts/jndi-host");

        // Set the ID
        digester.addCallMethod("service-locator/jndi-hosts/jndi-host/id", "setId", 1);
        digester.addCallParam("service-locator/jndi-hosts/jndi-host/id", 0);

        // Set the address
        digester.addCallMethod("service-locator/jndi-hosts/jndi-host/address", "setAddress", 1);
        digester.addCallParam("service-locator/jndi-hosts/jndi-host/address", 0);

        // Set the port
        digester.addCallMethod("service-locator/jndi-hosts/jndi-host/port", "setPort", 1,
                new Class[] { Integer.class });
        digester.addCallParam("service-locator/jndi-hosts/jndi-host/port", 0);

        // Add the JNP Host to the List
        digester.addSetNext("service-locator/jndi-hosts/jndi-host", "add");

    }

}