org.xwiki.contrib.nestedpagesmigrator.internal.serializer.MigrationPlanSerializer.java Source code

Introduction

Here is the source code for org.xwiki.contrib.nestedpagesmigrator.internal.serializer.MigrationPlanSerializer.java

Source

/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This 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 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.contrib.nestedpagesmigrator.internal.serializer;

import java.lang.reflect.Type;
import java.util.Collection;

import org.xwiki.contrib.nestedpagesmigrator.MigrationAction;
import org.xwiki.contrib.nestedpagesmigrator.MigrationPlanTree;
import org.xwiki.model.reference.DocumentReference;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

/**
 * Serialize a migration plan to a JSON tree.
 *  
 * @version $Id: $
 * @since 0.3
 */
public class MigrationPlanSerializer {
    private static class DocumentReferenceSerializer implements JsonSerializer<DocumentReference> {
        @Override
        public JsonElement serialize(DocumentReference src, Type typeOfSrc, JsonSerializationContext context) {
            return new JsonPrimitive(src.toString());
        }
    }

    private static class CollectionAdapter implements JsonSerializer<Collection<?>> {
        @Override
        public JsonElement serialize(Collection<?> src, Type typeOfSrc, JsonSerializationContext context) {
            if (src == null || src.isEmpty()) {
                return null;
            }

            // Otherwise, apply the standard strategy
            JsonArray array = new JsonArray();
            for (Object child : src) {
                JsonElement element = context.serialize(child);
                array.add(element);
            }
            return array;
        }
    }

    /**
     * Needed to not add the property "deletePrevious" when the value is false (to not pollute the plan too much)
     */
    private static class MigrationActionSerializer implements JsonSerializer<MigrationAction> {
        @Override
        public JsonElement serialize(MigrationAction src, Type typeOfSrc, JsonSerializationContext context) {
            JsonObject action = new JsonObject();
            action.add("sourceDocument", context.serialize(src.getSourceDocument()));
            action.add("targetDocument", context.serialize(src.getTargetDocument()));
            if (src.shouldDeletePrevious()) {
                action.addProperty("deletePrevious", Boolean.TRUE);
            }
            if (!src.isEnabled()) {
                action.addProperty("enabled", Boolean.FALSE);
            }
            action.add("preferences", context.serialize(src.getPreferences()));
            action.add("rights", context.serialize(src.getRights()));
            action.add("children", context.serialize(src.getChildren()));
            return action;
        }
    }

    private static Gson createSerializer() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder = gsonBuilder.registerTypeAdapter(DocumentReference.class, new DocumentReferenceSerializer());
        gsonBuilder = gsonBuilder.registerTypeHierarchyAdapter(Collection.class, new CollectionAdapter());
        gsonBuilder = gsonBuilder.registerTypeHierarchyAdapter(MigrationAction.class,
                new MigrationActionSerializer());
        gsonBuilder = gsonBuilder.setPrettyPrinting();
        return gsonBuilder.create();
    }

    /**
     * Serialize the migration plan to a JSON tree (as string).
     * @param planTree plan to serialize
     * @return the JSON tree as string
     */
    public static String serialize(MigrationPlanTree planTree) {
        return createSerializer().toJson(planTree.getTopLevelAction().getChildren());
    }

    /**
     * Serialize an arbitrary object to a JSON tree (as string).
     * @param object plan to serialize
     * @return the JSON tree as string
     */
    public static String serialize(Object object) {
        return createSerializer().toJson(object);
    }
}