com.strandls.alchemy.inject.AlchemyModuleFilterConfiguration.java Source code

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Here is the source code for com.strandls.alchemy.inject.AlchemyModuleFilterConfiguration.java

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/*
 * Copyright (C) 2015 Strand Life Sciences.
 *
 * 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 com.strandls.alchemy.inject;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.inject.Singleton;

import lombok.extern.slf4j.Slf4j;

import org.apache.commons.configuration.CompositeConfiguration;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.HierarchicalINIConfiguration;
import org.apache.commons.configuration.SystemConfiguration;
import org.apache.commons.lang3.ObjectUtils;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.strandls.alchemy.inject.AlchemyModule.Environment;

/**
 * {@link AlchemyModuleFilter} configuration for different environments.
 * Configuration for compatible environments is merged.
 *
 * @author Ashish Shinde
 *
 */
@Singleton
@Slf4j
public class AlchemyModuleFilterConfiguration {
    /**
     * The filter property used in the .ini file.
     */
    private static final String FILTER_PROPERTY = ".filter";

    /**
     * Name of the .ini file for configuration.
     */
    private static final String MODULE_CONFIGURATION_NAME = "alchemy-modules.ini";

    /**
     * Mapping from the environment to filter configuration.
     */
    private final Map<Environment, List<String>> environmentFilterConfig;

    /**
     * Creates the configuration object.
     */
    public AlchemyModuleFilterConfiguration() {
        environmentFilterConfig = new HashMap<>();
        loadConfiguration();
    }

    /**
     * Return the filter module filter regex list to use for an environment.
     * Includes filters for compatible environments as well.
     *
     * @param env
     *            the environment.
     * @return the the filter module filter regex list to use for the
     *         environment.
     */
    public Set<String> getFilterConfiguration(final Environment env) {
        final Set<String> filters = new HashSet<>();
        for (final Entry<Environment, List<String>> entry : environmentFilterConfig.entrySet()) {
            final Environment configEnv = entry.getKey();
            if (env.isCompatible(configEnv)) {
                // include filters from all compatible environments.
                filters.addAll(entry.getValue());
            }
        }
        return filters;
    }

    /**
     * Load filter configuration into the internal map.
     */
    private void loadConfiguration() {
        environmentFilterConfig.clear();
        final Configuration configuration = readConfiguration();
        for (final Environment env : Environment.values()) {
            final List<String> filterConfig = Lists.transform(configuration.getList(env.name() + FILTER_PROPERTY),
                    new Function<Object, String>() {

                        @Override
                        public String apply(final Object input) {
                            final String pattern = ObjectUtils.toString(input);
                            log.info("For environment {} found module filter pattern {} ", env, pattern);
                            return pattern;
                        }
                    });
            environmentFilterConfig.put(env, Collections.unmodifiableList(filterConfig));
        }
    }

    /**
     * @return configuration read from the config file.
     */
    private Configuration readConfiguration() {
        final CompositeConfiguration config = new CompositeConfiguration();
        config.addConfiguration(new SystemConfiguration());
        try {
            config.addConfiguration(new HierarchicalINIConfiguration(MODULE_CONFIGURATION_NAME));
        } catch (final ConfigurationException e) {
            // ignore if the configuration file is missing. This means no
            // filtering intended.
            log.warn("Error loading configuration file {}", e);
        }
        return config;
    }
}