org.nuiton.jpa.api.JpaEntities Maven / Gradle / Ivy

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package org.nuiton.jpa.api;

/*
 * #%L
 * Nuiton Jpa :: API
 * $Id:$
 * $HeadURL:$
 * %%
 * Copyright (C) 2013 CodeLutin
 * %%
 * This program 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 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 Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public 
 * License along with this program.  If not, see
 * .
 * #L%
 */

import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.Iterables;
import org.apache.commons.lang3.ObjectUtils;

import java.io.Serializable;
import java.util.Comparator;

/**
 * Helper class around {@link JpaEntity}.
 *
 * @author bleny 
 * @author tchemit 
 * @since 1.0
 */
public class JpaEntities {

    public static  E findById(Iterable entities, String id) {
        E result;
        if (entities == null) {
            result = null;
        } else {
            Optional eOptional = Iterables.tryFind(entities, entityHasId(id));
            result = eOptional.orNull();
        }
        return result;
    }

    public static class GetIdFunction implements Function {

        @Override
        public String apply(JpaEntity entity) {
            return entity.getId();
        }
    }

    public static class ArbitraryComparator implements Comparator, Serializable {

        private static final long serialVersionUID = 1L;

        @Override
        public int compare(E x, E y) {
            return ObjectUtils.compare(x.getId(), y.getId());
        }

    }

    public static Function getIdFunction() {
        return new GetIdFunction();
    }

    public static boolean isEntityHasId(JpaEntity entity, String id) {
        boolean result = entityHasId(id).apply(entity);
        return result;
    }

    public static boolean isEntityHasId(JpaEntity entity) {
        boolean result = entityHasId().apply(entity);
        return result;
    }

    public static boolean isEntityHasNoId(JpaEntity entity) {
        boolean result = entityHasNoId().apply(entity);
        return result;
    }

    public static Predicate entityHasId(String id) {
        return Predicates.compose(Predicates.equalTo(id), getIdFunction());
    }

    public static Predicate entityHasId() {
        return Predicates.compose(Predicates.notNull(), getIdFunction());
    }

    public static Predicate entityHasNoId() {
        return Predicates.compose(Predicates.equalTo(null), getIdFunction());
    }

    public static  Comparator arbitraryComparator() {
        return new ArbitraryComparator();
    }
}