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A generic CDI-based command framework

There is a newer version: 0.5.0

/*
 * Copyright 2019 Björn Kautler
 *
 * 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 net.kautler.command.api.restriction;

import javax.enterprise.context.ApplicationScoped;
import java.util.Collection;

import static java.util.Arrays.asList;

/**
 * A restriction that checks multiple other restrictions none of which may allow a command.
 * To use it, create a trivial subclass of this class and make it a discoverable CDI bean,
 * for example by annotating it with {@link ApplicationScoped @ApplicationScoped}.
 *
 * Example:
 * 
{@code
 * }@{@code ApplicationScoped
 * public class NeitherRoleANorRoleB extends NoneOf }{{@code
 *     }@{@code Inject
 *     private NeitherRoleANorRoleB(RoleA roleA, RoleB roleB) {
 *         super(roleA, roleB);
 *     }
 * }}{@code
 * }
 *
 * @param  the class of the messages for which this restriction can check allowance
 * @see AllOf
 * @see AnyOf
 */
public abstract class NoneOf implements Restriction {
    /**
     * The restrictions of which none may allow a command.
     */
    private final Collection> restrictions;

    /**
     * Constructs a new none-of restriction.
     *
     * @param restrictions the restrictions of which none may allow a command
     */
    @SafeVarargs
    public NoneOf(Restriction... restrictions) {
        this.restrictions = asList(restrictions);
    }

    @Override
    public boolean allowCommand(M message) {
        return restrictions.stream().noneMatch(restriction -> restriction.allowCommand(message));
    }
}