IniPIPConfigurationParserHelper.java

/*
 * Copyright (c) Members of the EGEE Collaboration. 2006-2010.
 * See http://www.eu-egee.org/partners/ for details on the copyright holders.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.glite.authz.pep.pip;

import java.util.List;
import java.util.StringTokenizer;

import org.glite.authz.common.config.AbstractConfigurationBuilder;
import org.glite.authz.common.config.ConfigurationException;
import org.glite.authz.common.config.IniConfigUtil;
import org.glite.authz.common.config.IniSectionConfigurationParser;
import org.glite.authz.common.util.LazyList;
import org.glite.authz.common.util.Strings;

import org.ini4j.Ini;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Helper for parsing configuration files which contain
 * {@link PolicyInformationPoint} declarations.
 */
public class IniPIPConfigurationParserHelper {

    /**
     * The name of the {@value} which gives the space-delimited lists of
     * to-be-configured PIPs.
     */
    public static final String PIP_PROP= "pips";

    /** Class logger. */
    private static final Logger LOG= LoggerFactory.getLogger(IniPIPConfigurationParserHelper.class);

    /**
     * Processing the {@value #PIP_PROP} configuration property, if there is
     * one.
     * 
     * @param iniFile
     *            INI configuration file being processed
     * @param configSection
     *            current configuration section being processed
     * @param configBuilder
     *            current builder being constructed from the parser
     * 
     * @return policy information points loaded based on the given configuration
     * 
     * @throws ConfigurationException
     *             thrown if there is a problem building the policy information
     *             points
     */
    public static List<PolicyInformationPoint> processPolicyInformationPoints(
            Ini iniFile, Ini.Section configSection,
            AbstractConfigurationBuilder<?> configBuilder)
            throws ConfigurationException {
        List<PolicyInformationPoint> pips= new LazyList<PolicyInformationPoint>();
        if (configSection.containsKey(PIP_PROP)) {
            String pipName;
            StringTokenizer pipNames= new StringTokenizer(configSection.get(PIP_PROP),
                                                          " ");
            while (pipNames.hasMoreTokens()) {
                pipName= Strings.safeTrimOrNullString(pipNames.nextToken());
                if (pipName != null) {
                    if (!iniFile.containsKey(pipName)) {
                        String errorMsg= "INI configuration file does not contain a configuration section for policy information point "
                                + pipName;
                        LOG.error(errorMsg);
                        throw new ConfigurationException(errorMsg);
                    }
                    PolicyInformationPoint pip= buildPolicyInformationPoint(iniFile.get(pipName),
                                                                            configBuilder);
                    pips.add(pip);
                    LOG.debug("loadded policy information point: {}", pipName);
                }
            }
        }
        return pips;
    }

    /**
     * Processes each individual PIP configuration section.
     * 
     * @param pipConfig
     *            the PIP configuration section
     * @param configBuilder
     *            configuration builder currently being populated
     * 
     * @return the PIP configured with the information provided in the
     *         configuration section
     * 
     * @throws ConfigurationException
     *             throw if a PIP can not be instantiated
     */
    @SuppressWarnings("unchecked")
    private static PolicyInformationPoint buildPolicyInformationPoint(
            Ini.Section pipConfig, AbstractConfigurationBuilder<?> configBuilder)
            throws ConfigurationException {
        String name= pipConfig.getName();
        LOG.info("Loading Policy Information Point {}", name);
        String parserClassName= IniConfigUtil.getString(pipConfig,
                                                        IniSectionConfigurationParser.PARSER_CLASS_PROP);

        try {
            Class<IniSectionConfigurationParser<PolicyInformationPoint>> parserClass= (Class<IniSectionConfigurationParser<PolicyInformationPoint>>) IniPIPConfigurationParserHelper.class.getClassLoader().loadClass(parserClassName);
            IniSectionConfigurationParser<PolicyInformationPoint> parser= parserClass.getConstructor().newInstance();
            return parser.parse(pipConfig, configBuilder);
        } catch (Exception e) {
            throw new ConfigurationException("Unable to configure PIP "
                                                     + name
                                                     + ". The following error was reported: "
                                                     + e.getMessage(),
                                             e);
        }
    }
}