org.eclipse.jgit.pgm.CommandRef.java Source code

Introduction

Here is the source code for org.eclipse.jgit.pgm.CommandRef.java

Source

/*
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.eclipse.jgit.pgm;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.text.MessageFormat;

import org.eclipse.jgit.pgm.internal.CLIText;

/**
 * Description of a command (a {@link org.eclipse.jgit.pgm.TextBuiltin}
 * subclass).
 * <p>
 * These descriptions are lightweight compared to creating a command instance
 * and are therefore suitable for catalogs of "known" commands without linking
 * the command's implementation and creating a dummy instance of the command.
 */
public class CommandRef {
    private final Class<? extends TextBuiltin> impl;

    private final String name;

    private String usage;

    boolean common;

    CommandRef(Class<? extends TextBuiltin> clazz) {
        this(clazz, guessName(clazz));
    }

    CommandRef(Class<? extends TextBuiltin> clazz, Command cmd) {
        this(clazz, cmd.name().length() > 0 ? cmd.name() : guessName(clazz));
        usage = cmd.usage();
        common = cmd.common();
    }

    private CommandRef(Class<? extends TextBuiltin> clazz, String cn) {
        impl = clazz;
        name = cn;
        usage = ""; //$NON-NLS-1$
    }

    private static String guessName(Class<? extends TextBuiltin> clazz) {
        final StringBuilder s = new StringBuilder();
        if (clazz.getName().startsWith("org.eclipse.jgit.pgm.debug.")) //$NON-NLS-1$
            s.append("debug-"); //$NON-NLS-1$

        boolean lastWasDash = true;
        for (char c : clazz.getSimpleName().toCharArray()) {
            if (Character.isUpperCase(c)) {
                if (!lastWasDash)
                    s.append('-');
                lastWasDash = !lastWasDash;
                s.append(Character.toLowerCase(c));
            } else {
                s.append(c);
                lastWasDash = false;
            }
        }
        return s.toString();
    }

    /**
     * Get the <code>name</code>.
     *
     * @return name the command is invoked as from the command line.
     */
    public String getName() {
        return name;
    }

    /**
     * Get <code>usage</code>.
     *
     * @return one line description of the command's feature set.
     */
    public String getUsage() {
        return usage;
    }

    /**
     * Is this command commonly used
     *
     * @return true if this command is considered to be commonly used.
     */
    public boolean isCommon() {
        return common;
    }

    /**
     * Get implementation class name
     *
     * @return name of the Java class which implements this command.
     */
    public String getImplementationClassName() {
        return impl.getName();
    }

    /**
     * Get implementation class loader
     *
     * @return loader for {@link #getImplementationClassName()}.
     */
    public ClassLoader getImplementationClassLoader() {
        return impl.getClassLoader();
    }

    /**
     * Create an instance of the command implementation
     *
     * @return a new instance of the command implementation.
     */
    public TextBuiltin create() {
        final Constructor<? extends TextBuiltin> c;
        try {
            c = impl.getDeclaredConstructor();
        } catch (SecurityException | NoSuchMethodException e) {
            throw new RuntimeException(MessageFormat.format(CLIText.get().cannotCreateCommand, getName(), e));
        }
        c.setAccessible(true);

        final TextBuiltin r;
        try {
            r = c.newInstance();
        } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
                | InvocationTargetException e) {
            throw new RuntimeException(MessageFormat.format(CLIText.get().cannotCreateCommand, getName(), e));
        }
        r.setCommandName(getName());
        return r;
    }

    /** {@inheritDoc} */
    @SuppressWarnings("nls")
    @Override
    public String toString() {
        return "CommandRef [impl=" + impl + ", name=" + name + ", usage="
                + CLIText.get().resourceBundle().getString(usage) + ", common=" + common + "]";
    }
}