tools/cli/src/main/java/org/apache/batchee/cli/BatchEECLI.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.batchee.cli;

import io.airlift.airline.Cli;
import io.airlift.airline.Help;
import io.airlift.airline.ParseException;
import org.apache.batchee.cli.command.Abandon;
import org.apache.batchee.cli.command.Executions;
import org.apache.batchee.cli.command.Instances;
import org.apache.batchee.cli.command.Names;
import org.apache.batchee.cli.command.Restart;
import org.apache.batchee.cli.command.Running;
import org.apache.batchee.cli.command.Start;
import org.apache.batchee.cli.command.Status;
import org.apache.batchee.cli.command.Stop;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.Enumeration;

import static java.lang.ClassLoader.getSystemClassLoader;

public class BatchEECLI {
    public static void main(final String[] args) {
        final Cli.CliBuilder<Runnable> builder = Cli.<Runnable>builder("batchee")
                .withDescription("BatchEE CLI")
                .withDefaultCommand(Help.class)
                .withCommands(Help.class,
                        Names.class,
                        Start.class, Restart.class,
                        Status.class, Running.class,
                        Stop.class, Abandon.class,
                        Instances.class, Executions.class);

        // user extension point
        try { // read manually cause we dont want to instantiate them there, so no ServiceLoader
            final ClassLoader tccl = Thread.currentThread().getContextClassLoader();
            final ClassLoader loader = tccl != null ? tccl : getSystemClassLoader();
            final Enumeration<URL> uc = loader.getResources("META-INF/services/org.apache.batchee.cli.command.UserCommand");
            while (uc.hasMoreElements()) {
                final URL url = uc.nextElement();
                BufferedReader r = null;
                try {
                    r = new BufferedReader(new InputStreamReader(url.openStream()));
                    String line;
                    while ((line = r.readLine()) != null) {
                        if (line.startsWith("#") || line.trim().isEmpty()) {
                            continue;
                        }
                        builder.withCommand(Class.class.cast(loader.loadClass(line.trim())));
                    }
                } catch (final IOException ioe) {
                    throw new IllegalStateException(ioe);
                } catch (final ClassNotFoundException cnfe) {
                    throw new IllegalArgumentException(cnfe);
                } finally {
                    if (r != null) {
                        r.close();
                    }
                }
            }
        } catch (final IOException e) {
            throw new IllegalStateException(e);
        }

        final Cli<Runnable> parser = builder.build();

        try {
            parser.parse(args).run();
        } catch (final ParseException e) {
            parser.parse("help").run();
        }
    }

    private BatchEECLI() {
        // no-op
    }
}