org.apache.james.utils.FileConfigurationProvider.java Source code

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Here is the source code for org.apache.james.utils.FileConfigurationProvider.java

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package org.apache.james.utils;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import javax.inject.Inject;
import javax.inject.Named;

import org.apache.commons.cli.MissingArgumentException;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.HierarchicalConfiguration;
import org.apache.commons.configuration.XMLConfiguration;
import org.apache.james.filesystem.api.FileSystem;
import org.apache.james.modules.CommonServicesModule;

import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.collect.Iterables;

public class FileConfigurationProvider implements ConfigurationProvider {

    private static final String CONFIGURATION_FILE_SUFFIX = ".xml";

    private final FileSystem fileSystem;
    private final String configurationPrefix;

    @Inject
    public FileConfigurationProvider(FileSystem fileSystem,
            @Named(CommonServicesModule.CONFIGURATION_PATH) String configurationPrefix)
            throws MissingArgumentException {
        this.fileSystem = fileSystem;
        this.configurationPrefix = configurationPrefix;
    }

    @Override
    public HierarchicalConfiguration getConfiguration(String component) throws ConfigurationException {
        Preconditions.checkNotNull(component);
        List<String> configPathParts = Splitter.on(".").splitToList(component);
        Preconditions.checkArgument(!configPathParts.isEmpty());
        HierarchicalConfiguration config = getConfig(retrieveConfigInputStream(configPathParts.get(0)));
        return selectHierarchicalConfigPart(config, Iterables.skip(configPathParts, 1));
    }

    private InputStream retrieveConfigInputStream(String configurationFileWithoutExtension)
            throws ConfigurationException {
        Preconditions.checkArgument(!Strings.isNullOrEmpty(configurationFileWithoutExtension),
                "The configuration file name should not be empty or null");
        try {
            return fileSystem.getResource(
                    configurationPrefix + configurationFileWithoutExtension + CONFIGURATION_FILE_SUFFIX);
        } catch (IOException e) {
            throw new ConfigurationException("Unable to locate configuration file "
                    + configurationFileWithoutExtension + CONFIGURATION_FILE_SUFFIX, e);
        }
    }

    private XMLConfiguration getConfig(InputStream configStream) throws ConfigurationException {
        XMLConfiguration config = new XMLConfiguration();
        config.setDelimiterParsingDisabled(true);
        config.setAttributeSplittingDisabled(true);
        config.load(configStream);
        return config;
    }

    private HierarchicalConfiguration selectHierarchicalConfigPart(HierarchicalConfiguration config,
            Iterable<String> configsPathParts) {
        HierarchicalConfiguration currentConfig = config;
        for (String nextPathPart : configsPathParts) {
            currentConfig = currentConfig.configurationAt(nextPathPart);
        }
        return currentConfig;
    }

}