ExternalParsersFactory.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.tika.parser.external;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.apache.tika.config.ServiceLoader;
import org.apache.tika.exception.TikaException;

/**
 * Creates instances of ExternalParser based on XML
 * configuration files.
 *
 * @see ExternalParsersConfigReader
 */
public class ExternalParsersFactory {

    public static List<ExternalParser> create() throws IOException, TikaException {
        return create(new ServiceLoader());
    }

    public static List<ExternalParser> create(ServiceLoader loader)
            throws IOException, TikaException {
        return create("tika-external-parsers.xml", loader);
    }

    public static List<ExternalParser> create(String filename, ServiceLoader loader)
            throws IOException, TikaException {
        String filepath =
                ExternalParsersFactory.class.getPackage().getName().replace('.', '/') + "/" +
                        filename;
        Enumeration<URL> files = loader.findServiceResources(filepath);
        ArrayList<URL> list = Collections.list(files);
        URL[] urls = list.toArray(new URL[0]);
        return create(urls);
    }

    public static List<ExternalParser> create(URL... urls) throws IOException, TikaException {
        List<ExternalParser> parsers = new ArrayList<>();
        for (URL url : urls) {
            try (InputStream stream = url.openStream()) {
                parsers.addAll(ExternalParsersConfigReader.read(stream));
            }
        }
        return parsers;
    }
}