net.conquiris.gson.GsonIndexInfo.java Source code

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Here is the source code for net.conquiris.gson.GsonIndexInfo.java

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/*
 * Copyright (C) the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.conquiris.gson;

import static com.google.common.base.Preconditions.checkArgument;

import java.lang.reflect.Type;
import java.util.Map.Entry;

import net.conquiris.api.index.IndexInfo;

import com.google.common.collect.ImmutableMap;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

/**
 * Gson representation for {@link IndexInfo}.
 * @author Andres Rodriguez
 */
public final class GsonIndexInfo implements JsonSerializer<IndexInfo>, JsonDeserializer<IndexInfo> {
    private static final String PROPERTIES = "properties";
    /** Number of documents. */
    private static final String N = "n";

    /** Constructor. */
    public GsonIndexInfo() {
    }

    @Override
    public JsonElement serialize(IndexInfo src, Type typeOfSrc, JsonSerializationContext context) {
        final JsonObject object = new JsonObject();
        if (src.getCheckpoint() != null) {
            object.addProperty(IndexInfo.CHECKPOINT_NAME, src.getCheckpoint());
        }
        if (src.getTargetCheckpoint() != null) {
            object.addProperty(IndexInfo.TARGET_CHECKPOINT_NAME, src.getTargetCheckpoint());
        }
        object.addProperty(N, src.getDocuments());
        object.addProperty(IndexInfo.TIMESTAMP_NAME, src.getTimestamp());
        object.addProperty(IndexInfo.SEQUENCE_NAME, src.getSequence());
        if (!src.getProperties().isEmpty()) {
            JsonObject properties = new JsonObject();
            for (Entry<String, String> entry : src.getProperties().entrySet()) {
                properties.addProperty(entry.getKey(), entry.getValue());
            }
            object.add(PROPERTIES, properties);
        }
        return object;
    }

    private String getOptionalString(JsonObject object, String key) {
        if (object.has(key)) {
            return object.getAsJsonPrimitive(key).getAsString();
        }
        return null;
    }

    @Override
    public IndexInfo deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        checkArgument(json.isJsonObject(), "Expected JSON Object to deserialize IndexInfo.");
        final JsonObject object = json.getAsJsonObject();
        final String checkpoint = getOptionalString(object, IndexInfo.CHECKPOINT_NAME);
        final String targetCheckpoint = getOptionalString(object, IndexInfo.TARGET_CHECKPOINT_NAME);
        final int documents = object.getAsJsonPrimitive(N).getAsInt();
        final long timestamp = object.getAsJsonPrimitive(IndexInfo.TIMESTAMP_NAME).getAsLong();
        final long sequence = object.getAsJsonPrimitive(IndexInfo.SEQUENCE_NAME).getAsLong();
        final ImmutableMap.Builder<String, String> b = ImmutableMap.builder();
        if (object.has(PROPERTIES)) {
            JsonObject properties = object.getAsJsonObject(PROPERTIES);
            for (Entry<String, JsonElement> entry : properties.entrySet()) {
                b.put(entry.getKey(), entry.getValue().getAsString());
            }
        }
        return IndexInfo.of(checkpoint, targetCheckpoint, documents, timestamp, sequence, b.build());
    }
}