neon.server.entity.EntityManager.java Source code

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Here is the source code for neon.server.entity.EntityManager.java

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/*
 *   Neon, a roguelike engine.
 *   Copyright (C) 2017-2018 - Maarten Driesen
 * 
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package neon.server.entity;

import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.concurrent.ExecutionException;
import java.util.logging.Logger;

import org.jdom2.Document;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import com.google.common.collect.HashBiMap;

import neon.common.entity.Entity;
import neon.common.files.NeonFileSystem;
import neon.common.files.XMLTranslator;
import neon.common.resources.Resource;
import neon.common.resources.ResourceException;

/**
 * This class manages all loaded entities in the current game (and by extension
 * all loaded modules and maps). 
 * 
 * @author mdriesen
 *
 */
public final class EntityManager {
    private static final Logger logger = Logger.getGlobal();

    private final Cache<Long, Entity> entities = CacheBuilder.newBuilder().removalListener(new EntityListener())
            .softValues().build();
    private final HashMap<Class<?>, EntityBuilder> builders = new HashMap<>();
    private final EntitySaver saver;
    private final NeonFileSystem files;
    private final Cache<Integer, Map> maps = CacheBuilder.newBuilder().removalListener(new MapListener())
            .softValues().build();
    private final HashBiMap<String, Short> uids = HashBiMap.create();

    public EntityManager(NeonFileSystem files, EntitySaver saver) {
        this.files = files;
        this.saver = saver;
    }

    /**
     * Returns the entity with the given uid. If the entity is not present, an
     * {@code IllegalArgumentException} is thrown.
     * 
     * @param uid
     * @return
     */
    public Entity getEntity(long uid) {
        try {
            return entities.get(uid, () -> loadEntity(uid));
        } catch (ExecutionException e) {
            throw new IllegalArgumentException("No entity with uid <" + uid + "> found", e);
        }
    }

    /**
     * Calculates the full map uid given the module name and the base uid
     * of the map within the module.
     * 
     * @param base
     * @param module
     * @return
     */
    public int getMapUID(short base, String module) {
        return ((int) getModuleUID(module) << 16) | base;
    }

    public Map getMap(Integer uid) {
        return maps.getIfPresent(uid);
    }

    public void addMap(Map map) {
        maps.put(map.getUid(), map);
    }

    public <T extends Resource> void addBuilder(Class<T> type, EntityBuilder<? super T> builder) {
        builders.put(type, builder);
    }

    public void removeEntity(long uid) {
        entities.invalidate(uid);
    }

    /**
     * Creates a new entity from the given resource and uid. The new entity
     * is added to the cache.
     * 
     * @param uid
     * @param resource
     * @return
     */
    @SuppressWarnings("unchecked")
    public Entity createEntity(long uid, Resource resource) {
        Entity entity = builders.get(resource.getClass()).build(uid, resource);
        entities.put(uid, entity);
        return entity;
    }

    public Collection<Entity> getEntities() {
        return entities.asMap().values();
    }

    /**
     * 
     * @param entity
     * @return   the uid of the module an entity belongs to
     */
    short getModuleUID(long entity) {
        return (short) (entity >>> 48);
    }

    /**
     * Stores all remaining entities in the cache in the temp folder on disk.
     */
    public void flush() {
        entities.asMap().values().forEach(entity -> saveEntity(entity));
    }

    public long getFreeUID() {
        long uid = 256;
        while (entities.asMap().containsKey(uid)) {
            uid++;
        }
        return uid;
    }

    private void saveEntity(Entity entity) {
        Document doc = new Document(saver.save(entity));
        try {
            files.saveFile(doc, new XMLTranslator(), "entities", Long.toString(entity.uid) + ".xml");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private Entity loadEntity(long uid) throws IOException, ResourceException {
        Document doc = files.loadFile(new XMLTranslator(), "entities", Long.toString(uid) + ".xml");
        return saver.load(uid, doc.getRootElement());
    }

    /**
     * 
     * @param module
     * @return   the uid of the module
     */
    public short getModuleUID(String module) {
        return uids.get(module);
    }

    /**
     * Sets the uid of the given module. If another module with the same uid 
     * was already present, this module is moved to the next free uid.
     * 
     * @param module
     * @param uid
     */
    public void setModuleUID(String module, short uid) {
        if (uids.containsValue(uid)) {
            String mod = uids.inverse().get(uid);
            short index = 0;
            while (uids.containsValue(++index))
                ;
            uids.put(mod, index);
        }

        uids.put(module, uid);
    }

    private final class EntityListener implements RemovalListener<Long, Entity> {
        @Override
        public void onRemoval(RemovalNotification<Long, Entity> notification) {
            logger.finest(notification.getValue() + " removed from manager");
            saveEntity(notification.getValue());
        }
    }

    private final class MapListener implements RemovalListener<Integer, Map> {
        @Override
        public void onRemoval(RemovalNotification<Integer, Map> notification) {
            logger.finest(notification.getValue() + " removed from manager");
        }
    }
}