edu.sabanciuniv.sentilab.sare.controllers.base.PersistentObjectFactory.java Source code

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/*
 * Sentilab SARE: a Sentiment Analysis Research Environment
 * Copyright (C) 2013 Sabanci University Sentilab
 * http://sentilab.sabanciuniv.edu
 * 
 * This file is part of SARE.
 * 
 * SARE 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.
 *  
 * SARE 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 SARE. If not, see <http://www.gnu.org/licenses/>.
 */

package edu.sabanciuniv.sentilab.sare.controllers.base;

import java.util.UUID;
import java.util.Map.Entry;

import javax.persistence.EntityManager;

import org.apache.commons.lang3.StringUtils;

import com.google.common.reflect.TypeToken;
import com.google.gson.*;

import edu.sabanciuniv.sentilab.core.controllers.factory.Factory;
import edu.sabanciuniv.sentilab.core.models.factory.IllegalFactoryOptionsException;
import edu.sabanciuniv.sentilab.sare.models.base.*;
import edu.sabanciuniv.sentilab.utils.UuidUtils;

/**
 * The base class for all factories that create {@link PersistentObject} instances.
 * @author Mus'ab Husaini
 * @param <T> the type of object that will be created; must derive from {@link PersistentObject}.
 */
public abstract class PersistentObjectFactory<T extends PersistentObject> extends ControllerBase
        implements Factory<T> {

    protected byte[] existingId;
    protected String otherData;
    protected EntityManager em;

    /**
     * Gets the ID of an existing object to be modified.
     * @return the ID to fetch the object with.
     */
    public byte[] getExistingId() {
        return this.existingId;
    }

    /**
     * Sets the ID of an existing object to be modified. Must also provide a non-{@code null} value for {@code em}
     * if this is {@code null}
     * @param id the ID to fetch the object with.
     * @return the {@code this} object.
     */
    public PersistentObjectFactory<T> setExistingId(byte[] id) {
        this.existingId = id;
        return this;
    }

    /**
     * Sets the ID of an existing object to be modified. Must also provide a non-{@code null} value for {@code em}
     * if this is {@code null}
     * @param id the ID to fetch the object with.
     * @return the {@code this} object.
     */
    public PersistentObjectFactory<T> setExistingId(String id) {
        if (StringUtils.isEmpty(id)) {
            return this;
        }

        return this.setExistingId(UuidUtils.toBytes(id));
    }

    /**
     * Sets the ID of an existing object to be modified. Must also provide a non-{@code null} value for {@code em}
     * if this is {@code null}
     * @param id the ID to fetch the object with.
     * @return the {@code this} object.
     */
    public PersistentObjectFactory<T> setExistingId(UUID id) {
        if (id == null) {
            return this;
        }

        return this.setExistingId(UuidUtils.toBytes(id));
    }

    /**
     * Gets any other data to be attached to the target object.
     * @return the {@link String} representing other data.
     */
    public String getOtherData() {
        return this.otherData;
    }

    /**
     * Sets any other data to attach to the target object.
     * @param otherData the {@link String} representing any other data (must be valid JSON).
     * @return the {@code this} object.
     * @throws IllegalArgumentException when the argument cannot be parsed as a JSON object.
     */
    public PersistentObjectFactory<T> setOtherData(String otherData) {
        if (otherData != null) {
            try {
                if (!new JsonParser().parse(otherData).isJsonObject()) {
                    throw new JsonSyntaxException("");
                }
            } catch (JsonSyntaxException e) {
                throw new IllegalArgumentException("argument 'otherData' must be valid JSON", e);
            }
        }

        this.otherData = otherData;
        return this;
    }

    /**
     * Gets an entity manager that will be used in case an ID was provided.
     * @return the {@link EntityManager} that will be used.
     */
    public EntityManager getEm() {
        return this.em;
    }

    /**
     * Sets the entity manager to use in case an ID was provided. Only needed if an existing ID was provided.
     * @param em the {@link EntityManager} to be set.
     * @return the {@code this} object.
     */
    public PersistentObjectFactory<T> setEm(EntityManager em) {
        this.em = em;
        return this;
    }

    protected abstract T createPrivate(T existing) throws IllegalFactoryOptionsException;

    @SuppressWarnings({ "unchecked", "serial" })
    @Override
    public T create() throws IllegalFactoryOptionsException {

        try {
            T obj = null;
            if (this.getExistingId() != null && this.getEm() != null) {
                obj = (T) this.getEm().find(new TypeToken<T>(this.getClass()) {
                }.getRawType(), this.getExistingId());
            }

            obj = this.createPrivate(obj);

            // merge the other data.
            if (obj != null && this.getOtherData() != null) {
                JsonObject otherData = new JsonParser().parse(this.getOtherData()).getAsJsonObject();
                for (Entry<String, JsonElement> dataEntry : otherData.entrySet()) {
                    if (!obj.hasProperty(dataEntry.getKey())) {
                        obj.setProperty(dataEntry.getKey(), dataEntry.getValue());
                    }
                }
            }

            return obj;
        } catch (NullPointerException e) {
            throw new IllegalFactoryOptionsException(e);
        }
    }
}