com.github.rvesse.airline.examples.inheritance.GoodGrandchild Maven / Gradle / Ivy

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Provides a variety of examples of using Airline
There is a newer version: 3.0.0
/**
 * Copyright (C) 2010-16 the original author or authors.
 *
 * 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 com.github.rvesse.airline.examples.inheritance;

import com.github.rvesse.airline.annotations.Command;
import com.github.rvesse.airline.annotations.Option;
import com.github.rvesse.airline.examples.ExampleExecutor;
import com.github.rvesse.airline.examples.modules.Modules;

/**
 * When inheriting from existing classes it is possible to override previously
 * defined options but only if you are explicit about it. In this case Airline
 * uses the bottom-most definition of the option as the effective definition
 * 
 * Note that any values set for options are propagated to all declarations in
 * the inheritance tree since an ancestor class will not have access to fields
 * set in the descendants.
 * 
 *
 */
@Command(name = "good-grandchild", description = "A legal command which overrides an option defined by a parent")
public class GoodGrandchild extends Child {

    /**
     * We can override the definition of an existing option under certain
     * conditions:
     * 
     * {@code arity}, {@code name} and {@code optionType} are unchanged
     * Type is same or a valid narrowing conversion exists from the
     * inherited option type to the overridden type
     * You explicitly declare {@code override} to be {@code true} and the
     * inherited option does not define {@code sealed} to be {@code true}
     * 
     * 
     * In practise this means you can change some informative properties of the
     * option such as the title and description. You can also choose to make it
     * visible/hidden and required/not required as desired.
     * 
     * 
     * Note that often if you find yourself needing to override options
     * frequently then this can be indicative of poorly thought out option
     * inheritance in which case using modules may be a better option. See
     * {@link Modules} for an example of this.
     * 
     */
    @Option(name = "--parent", description = "An option can be overridden if we are explicit about it", override = true)
    private boolean parent;

    public static void main(String[] args) {
        ExampleExecutor.executeSingleCommand(GoodGrandchild.class, args);
    }
}