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Eclipse Ditto is a framework for creating and managing digital twins in the IoT.
There is a newer version: 3.7.1
/*
 * Copyright (c) 2017 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 */
package org.eclipse.ditto.base.api.common;

import static org.eclipse.ditto.base.model.common.ConditionChecker.checkNotNull;

import java.util.Objects;
import java.util.function.Predicate;

import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;

import org.eclipse.ditto.json.JsonFactory;
import org.eclipse.ditto.json.JsonField;
import org.eclipse.ditto.json.JsonFieldDefinition;
import org.eclipse.ditto.json.JsonObject;
import org.eclipse.ditto.json.JsonObjectBuilder;
import org.eclipse.ditto.base.model.headers.DittoHeaders;
import org.eclipse.ditto.base.model.json.FieldType;
import org.eclipse.ditto.base.model.json.JsonParsableCommand;
import org.eclipse.ditto.base.model.json.JsonSchemaVersion;
import org.eclipse.ditto.base.model.signals.commands.Command;
import org.eclipse.ditto.base.model.signals.commands.CommandJsonDeserializer;

/**
 * Command for shutting down arbitrary parts of the system.
 * Each recipient decides whether it accepts the provided reason of this command or if it ignores the command.
 */
@Immutable
@JsonParsableCommand(typePrefix = CommonCommand.TYPE_PREFIX, name = Shutdown.NAME)
public final class Shutdown extends CommonCommand {

    /**
     * The name of the {@code Shutdown} command.
     */
    static final String NAME = "shutdown";

    /**
     * The type of the {@code Shutdown} command.
     */
    public static final String TYPE = TYPE_PREFIX + NAME;

    private final ShutdownReason reason;

    private Shutdown(final ShutdownReason theReason, final DittoHeaders dittoHeaders) {
        super(TYPE, Category.MODIFY, dittoHeaders);
        reason = checkNotNull(theReason, "ShutdownReason");
    }

    /**
     * Returns an instance of {@code Shutdown}.
     *
     * @param shutdownReason the reason for the returned command.
     * @param dittoHeaders the headers of the returned command.
     * @return the instance.
     * @throws NullPointerException if any argument is {@code null}.
     */
    public static Shutdown getInstance(final ShutdownReason shutdownReason, final DittoHeaders dittoHeaders) {
        return new Shutdown(shutdownReason, dittoHeaders);
    }

    /**
     * Creates a new {@code Shutdown} from the given JSON object.
     *
     * @param jsonObject the JSON object of which the Shutdown is to be created.
     * @param dittoHeaders the headers.
     * @return the command.
     * @throws NullPointerException if {@code jsonObject} is {@code null}.
     * @throws org.eclipse.ditto.json.JsonMissingFieldException if {@code jsonObject} did not contain
     * {@link Shutdown.JsonFields#REASON}.
     * @throws org.eclipse.ditto.json.JsonParseException if the passed in {@code jsonObject} was not in the expected
     * format.
     */
    public static Shutdown fromJson(final JsonObject jsonObject, final DittoHeaders dittoHeaders) {
        return new CommandJsonDeserializer(TYPE, jsonObject).deserialize(
                () -> getInstance(ShutdownReasonFactory.fromJson(
                        jsonObject.getValue(JsonFields.REASON).orElseGet(JsonObject::empty)),
                        dittoHeaders));
    }

    /**
     * Returns the reason for issuing this command.
     *
     * @return the reason of this command.
     */
    public ShutdownReason getReason() {
        return reason;
    }

    @Override
    protected void appendPayload(final JsonObjectBuilder jsonObjectBuilder, final JsonSchemaVersion schemaVersion,
            final Predicate predicate) {

        final Predicate isNonEmptyObject =
                field -> field.getValue().isObject() && !field.getValue().asObject().isEmpty();

        jsonObjectBuilder.set(JsonFields.REASON, reason.toJson(schemaVersion, predicate),
                schemaVersion.and(predicate).and(predicate).and(isNonEmptyObject));
    }

    @Override
    public Shutdown setDittoHeaders(final DittoHeaders dittoHeaders) {
        if (Objects.equals(getDittoHeaders(), dittoHeaders)) {
            return this;
        }
        return new Shutdown(reason, dittoHeaders);
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        if (!super.equals(o)) {
            return false;
        }
        final Shutdown that = (Shutdown) o;
        return that.canEqual(this) && Objects.equals(reason, that.reason) && super.equals(that);
    }

    @Override
    protected boolean canEqual(@Nullable final Object other) {
        return other instanceof Shutdown;
    }

    @Override
    public int hashCode() {
        return Objects.hash(super.hashCode(), reason);
    }

    @Override
    public String toString() {
        return getClass().getSimpleName() + " [" +
                super.toString() +
                ", reason=" + reason +
                "]";
    }

    /**
     * This class contains definitions for all specific fields of a {@code ShutdownCommand}'s JSON representation.
     */
    @Immutable
    public static final class JsonFields extends Command.JsonFields {

        public static final JsonFieldDefinition REASON = JsonFactory.newJsonObjectFieldDefinition("reason",
                FieldType.REGULAR, JsonSchemaVersion.V_2);

        private JsonFields() {
            throw new AssertionError();
        }

    }

}