de.tudarmstadt.ukp.dkpro.lexsemresource.core.ResourceFactory.java Source code

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/*******************************************************************************
 * Copyright 2012
 * Ubiquitous Knowledge Processing (UKP) Lab
 * Technische Universitt Darmstadt
 *
 * 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 de.tudarmstadt.ukp.dkpro.lexsemresource.core;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.springframework.context.support.FileSystemXmlApplicationContext;

import de.tudarmstadt.ukp.dkpro.lexsemresource.LexicalSemanticResource;
import de.tudarmstadt.ukp.dkpro.lexsemresource.exception.ResourceLoaderException;

/**
 * Class for loading diverse resources, implementing the LexicalSemanticResource
 * interface, with fewer parameters.
 *
 * @author Richard Eckart de Castilho
 */
public class ResourceFactory {
    public static final String ENV_DKPRO_HOME = "DKPRO_HOME";
    public final static String CONFIG_FILE = "resources.xml";

    private static ResourceFactory loader;

    private FileSystemXmlApplicationContext context;

    public static synchronized ResourceFactory getInstance() throws ResourceLoaderException {
        if (loader == null) {
            List<String> locs = new ArrayList<String>();
            URL resourceXmlUrl = null;

            // Check in workspace
            try {
                File f = new File(getWorkspace(), CONFIG_FILE);
                if (f.isFile()) {
                    try {
                        resourceXmlUrl = f.toURI().toURL();
                    } catch (MalformedURLException e) {
                        throw new ResourceLoaderException(e);
                    }
                }
                locs.add(f.getAbsolutePath());
            } catch (IOException e) {
                locs.add("DKPro workspace not available");
            }

            // Check in classpath
            if (resourceXmlUrl == null) {
                resourceXmlUrl = ResourceFactory.class.getResource(CONFIG_FILE);
                locs.add("Classpath: " + CONFIG_FILE);
            }

            // Check in default file system location
            if (resourceXmlUrl == null && new File(CONFIG_FILE).isFile()) {
                try {
                    resourceXmlUrl = new File(CONFIG_FILE).toURI().toURL();
                } catch (MalformedURLException e) {
                    throw new ResourceLoaderException(e);
                }
                locs.add(new File(CONFIG_FILE).getAbsolutePath());
            }

            // Bail out if still not found
            if (resourceXmlUrl == null) {
                throw new ResourceLoaderException(
                        "Unable to locate configuration file [" + CONFIG_FILE + "] in " + locs.toString());
            }

            loader = new ResourceFactory(resourceXmlUrl.toString());
        }
        return loader;
    }

    /**
     * Constructor parameterized by the path to the configuration file.
     *
     * @param location location of the configuration file.
     */
    public ResourceFactory(String location) {
        context = new FileSystemXmlApplicationContext(location);
    }

    /**
     * Standard function to get a resource object specified by name and
     * language.
     *
     * @param name
     *            String
     * @param lang
     *            String
     * @return LexicalSemanticResource
     * @throws ResourceLoaderException
     */
    public LexicalSemanticResource get(String name, String lang) throws ResourceLoaderException {
        return (LexicalSemanticResource) context.getBean(name + "-" + lang, LexicalSemanticResource.class);
    }

    /**
     * @return All registered resources. ResourceLoaderExceptions are catched
     *         and ignored to all for easy iteration over all resources runnalbe
     *         on the current system.
     */
    public Collection<LexicalSemanticResource> getAll() {
        return context.getBeansOfType(LexicalSemanticResource.class).values();
    }

    /**
     * Get the workspace directory.
     *
     * @return the workspace directory.
     * @throws IOException if the workspace cannot be obtained
     */
    private static File getWorkspace() throws IOException {
        if (System.getenv(ENV_DKPRO_HOME) != null) {
            File f = new File(System.getenv(ENV_DKPRO_HOME));
            return new File(f, ResourceFactory.class.getName());
        }

        throw new IOException("Environment variable [" + ENV_DKPRO_HOME + "] not set");
    }
}