name.livitski.tools.springlet.commands.HelpCommand.java Source code

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Here is the source code for name.livitski.tools.springlet.commands.HelpCommand.java

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/**
 *    Copyright  2013 Konstantin "Stan" Livitski
 * 
 *    This file is part of Springlet. Springlet is
 *    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 name.livitski.tools.springlet.commands;

import java.util.ArrayList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.ListableBeanFactory;

import name.livitski.tools.springlet.ApplicationBean;
import name.livitski.tools.springlet.Command;
import name.livitski.tools.springlet.Launcher;
import name.livitski.tools.springlet.SkipApplicationRunRequest;

/**
 * Handles the <code>--help</code> command line switch.
 * Displays the {@link #usage() application's usage summary} and
 * {@link SkipApplicationRunRequest requests the framework to quit}.
 */
public class HelpCommand extends Command implements BeanFactoryAware {
    /**
     * @param manager the data manager that may receive this
     * command
     */
    public HelpCommand(ApplicationBean manager) {
        super(manager);
    }

    @Override
    public void process(ListIterator<String> args) {
        usage();
        throw new SkipApplicationRunRequest();
    }

    /**
     * Displays the application's usage summary obtained by polling all
     * {@link Command command beans} defined in its configuration.
     */
    public void usage() {
        System.out.println("Usage summary:");
        System.out.printf(" java -cp {classpath} [vm-args] run [args]%n%n");
        System.out.println(" where: args := arg [args] ;");
        System.out.println("  arg is one of the following:");
        Map<String, Command> commands = beanFactory.getBeansOfType(Command.class);
        StringBuilder tagSpec = new StringBuilder(512);
        List<String> cmdsTags = new ArrayList<String>();
        for (final Map.Entry<String, Command> entry : commands.entrySet()) {
            final Command cmd = entry.getValue();
            final String id = entry.getKey();
            tagSpec.setLength(0);
            cmdsTags.clear();
            cmdsTags.add(id);
            final String[] aliases = beanFactory.getAliases(id);
            for (String alias : aliases)
                cmdsTags.add(alias);
            for (String tag : cmdsTags) {
                if (tag.startsWith(Launcher.BEAN_NAME_PREFIX_COMMAND))
                    tag = COMMAND_PREFIX + tag.substring(Launcher.BEAN_NAME_PREFIX_COMMAND.length());
                else if (tag.startsWith(Launcher.BEAN_NAME_PREFIX_SWITCH))
                    tag = SWITCH_PREFIX + tag.substring(Launcher.BEAN_NAME_PREFIX_SWITCH.length());
                else if (tag.equals(Launcher.BEAN_NAME_DEFAULT_HANDLER))
                    continue;
                if (0 != tagSpec.length())
                    tagSpec.append(", ");
                tagSpec.append(tag);
            }
            String argspec = cmd.getArgSpec();
            System.out.printf("%n %s%s%n", tagSpec, null == argspec ? "" : " " + argspec);
            System.out.printf("%n   %s%n", cmd.getSummary());
        }
        System.out.println();
    }

    @Override
    public String getArgSpec() {
        return null;
    }

    @Override
    public String getSummary() {
        return "Displays this help screen and exits.";
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        if (!(beanFactory instanceof ListableBeanFactory))
            throw new UnsupportedOperationException(
                    "Beans of " + getClass() + " require a ListableBeanFactory container");
        this.beanFactory = (ListableBeanFactory) beanFactory;
    }

    private ListableBeanFactory beanFactory;
}