jease.cms.service.Revisions.java Source code

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Here is the source code for jease.cms.service.Revisions.java

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/*
Copyright (C) 2016 maik.jablonski@jease.org
    
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 jease.cms.service;

import java.util.ArrayList;
import java.util.List;

import jease.Names;
import jease.Registry;
import jease.cmf.service.Nodes;
import jease.cmf.service.Revisioner;
import jease.cms.domain.Content;
import jease.cms.domain.Version;
import jfix.db4o.Database;

import org.apache.commons.lang3.math.NumberUtils;

/**
 * Service to create/restore content-revisions. Each content revision is stored
 * within an array (newest revision is first element of array), so overhead is
 * neglectable.
 * 
 * The minimum number of revisions to be kept is returned by {@link #getCount()}
 * (default: -1 = unlimited, 0 = ignore).
 * 
 * The number of days for which revisions in the past should be kept is returned
 * by {@link #getDays()} (default: -1 = unlimited, 0 = ignore).
 */
public class Revisions {

    /**
     * Minimum count of revisions to be kept. -1 means unlimited.
     */
    public static int getCount() {
        return NumberUtils.toInt(Registry.getParameter(Names.JEASE_REVISION_COUNT), -1);
    }

    /**
     * Number of days in the past for which revisions should be kept. -1 means
     * unlimited.
     */
    public static int getDays() {
        return NumberUtils.toInt(Registry.getParameter(Names.JEASE_REVISION_DAYS), -1);
    }

    /**
     * Returns true if getDays() or getCount() is not null.
     */
    public static boolean isConfigured() {
        return getCount() != 0 || getDays() != 0;
    }

    private final static Revisioner revisioner = new Revisioner(Contents.getAvailableTypes());

    /**
     * Add new revision for given content.
     */
    public static void checkin(Content content) {
        checkin(null, content);
    }

    /**
     * Add new revision with given info (e.g. username) for given content.
     */
    public static void checkin(String info, Content content) {
        content.addRevision(new Version(info, revisioner.toBlob(content)));
        purge(content, getCount(), getDays());
    }

    /**
     * Returns the given revision (by index) for given content.
     */
    public static <E extends Content> E checkout(E content, int revision) {
        return (E) revisioner.fromBlob(content.getRevisions()[revision].getBlob());
    }

    /**
     * Keeps only revisions for given content below given count and given days.
     * Returns number of purged revisions. Setting count or days to 0 means to
     * ignore it, -1 means unlimited.
     */
    public static int purge(Content content, int count, int days) {
        if (count == -1 || days == -1 || content.getRevisions() == null) {
            return 0;
        }
        int revisionsBefore = content.getRevisions().length;
        long daysInPast = System.currentTimeMillis() - (days * 24L * 3600L * 1000L);
        List<Version> revisions = new ArrayList<Version>();
        for (Version version : content.getRevisions()) {
            if ((count > 0 && revisions.size() < count)
                    || (days > 0 && version.getBlob().getFile().lastModified() > daysInPast)) {
                revisions.add(version);
            }
        }
        content.setRevisions(revisions.toArray(new Version[] {}));
        return revisionsBefore - content.getRevisions().length;
    }

    /**
     * Keeps only revisions for given contents of given class for given count
     * and given days. Returns number of purged revisions. Setting count or days
     * to 0 means to ignore it, -1 means unlimited.
     */
    public static int purge(Class<Content> clazz, int count, int days) {
        int result = 0;
        for (Content content : Nodes.getRoot().getDescendants(clazz)) {
            result += Revisions.purge(content, count, days);
            Nodes.save(content);
        }
        Database.ext().gc();
        return result;
    }

    /**
     * Returns the number of revisions for given content class.
     */
    public static int getNumber(Class<? extends Content> clazz) {
        int number = 0;
        for (Content content : Database.query(clazz)) {
            if (content.getRevisions() != null) {
                number += content.getRevisions().length;
            }
        }
        return number;
    }
}