org.btrplace.plan.event.Action Maven / Gradle / Ivy

Go to download
/*
 * Copyright (c) 2016 University Nice Sophia Antipolis
 *
 * This file is part of btrplace.
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 */

package org.btrplace.plan.event;

import org.btrplace.model.Model;

import java.util.*;
import java.util.stream.Collectors;

/**
 * An action is an event that has to be scheduled for reliability purpose.
 * 
 * An action may embed several other events. Events are attach to the actions
 * using {@link Hook}.
 * hook.
 *
 * @author Fabien Hermenier
 */
public abstract class Action implements Event {

    /**
     * Possible moments where an event can be considered.
     */
    public enum Hook {
        /**
         * The event can be considered before executing the action.
         */
        PRE("pre"),
        /**
         * The event can be considered after the action execution.
         */
        POST("post");

        private String name;

        /**
         * new hook
         *
         * @param v the pretty name
         */
        Hook(String v) {
            this.name = v;
        }


        @Override
        public String toString() {
            return this.name;
        }
    }

    private int start;

    private int stop;

    private EnumMap> events;

    /**
     * Create an action.
     *
     * @param st the moment the action starts
     * @param ed the moment the action ends
     */
    public Action(int st, int ed) {
        this.start = st;
        this.stop = ed;
        events = new EnumMap<>(Hook.class);
    }

    /**
     * Apply the action on a model.
     * In practice, the events attached to {@link Hook#PRE} are executed in first,
     * then {@link #applyAction(org.btrplace.model.Model)} is called. Finally,
     * the events attached to {@link Hook#POST} are executed.
     *
     * @param i the instance to alter with the action
     * @return {@code true} if the action and all the events were applied successfully
     */
    @Override
    public boolean apply(Model i) {
        return applyEvents(Hook.PRE, i) && applyAction(i) && applyEvents(Hook.POST, i);
    }

    /**
     * Apply the events attached to a given hook.
     *
     * @param k the hook
     * @param i the model to modify with the application of the events
     * @return {@code true} iff all the events were applied successfully
     */
    public boolean applyEvents(Hook k, Model i) {
        for (Event n : getEvents(k)) {
            if (!n.apply(i)) {
                return false;
            }
        }
        return true;
    }

    /**
     * Apply only the scheduled action.
     *
     * @param i the model to modify
     * @return {@code true} if the action was applied successfully
     */
    public abstract boolean applyAction(Model i);

    /**
     * Get the moment the action starts.
     *
     * @return a positive integer
     */
    public int getStart() {
        return start;
    }

    /**
     * Get the moment the action ends.
     *
     * @return a positive integer
     */
    public int getEnd() {
        return stop;
    }


    /**
     * Add an event to the action.
     * The moment the event will be executed depends on its hook.
     *
     * @param k the hook
     * @param n the event to attach
     * @return {@code true} iff the event was added
     */
    public boolean addEvent(Hook k, Event n) {
        Set l = events.get(k);
        if (l == null) {
            l = new HashSet<>();
            events.put(k, l);
        }
        return l.add(n);
    }

    /**
     * Get the events attached to a specific hook.
     *
     * @param k the hook
     * @return a list of events that may be empty
     */
    public Set getEvents(Hook k) {
        Set l = events.get(k);
        return l == null ? Collections.emptySet() : l;
    }

    /**
     * Pretty print of the action.
     *
     * @return a String
     */
    public abstract String pretty();

    @Override
    public String toString() {
        StringBuilder b = new StringBuilder();
        b.append("{action=").append(pretty());
        if (!events.isEmpty()) {
            for (Map.Entry> entry : events.entrySet()) {
                Set l = entry.getValue();
                Hook k = entry.getKey();
                b.append(", @").append(k).append("= {");
                b.append(l.stream().map(e -> l.toString()).collect(Collectors.joining(", ")));
                b.append('}');
            }
        }
        b.append('}');
        return b.toString();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        Action action = (Action) o;

        return start == action.start && stop == action.stop && events.equals(action.events);
    }

    @Override
    public int hashCode() {
        return Objects.hash(start, stop, events);
    }
}