com.cedarsoft.couchdb.io.ViewResponseSerializer.java Source code

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Here is the source code for com.cedarsoft.couchdb.io.ViewResponseSerializer.java

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/**
 * Copyright (C) cedarsoft GmbH.
 *
 * Licensed under the GNU General Public License version 3 (the "License")
 * with Classpath Exception; you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *         http://www.cedarsoft.org/gpl3ce
 *         (GPL 3 with Classpath Exception)
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 3 only, as
 * published by the Free Software Foundation. cedarsoft GmbH designates this
 * particular file as subject to the "Classpath" exception as provided
 * by cedarsoft GmbH in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 3 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 3 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact cedarsoft GmbH, 72810 Gomaringen, Germany,
 * or visit www.cedarsoft.com if you need additional information or
 * have any questions.
 */

package com.cedarsoft.couchdb.io;

import com.cedarsoft.couchdb.core.Row;
import com.cedarsoft.couchdb.core.ViewResponse;
import com.cedarsoft.serialization.jackson.InvalidTypeException;
import com.cedarsoft.serialization.jackson.JacksonParserWrapper;
import com.cedarsoft.serialization.jackson.JacksonSerializer;
import com.cedarsoft.serialization.jackson.JacksonSupport;
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

public class ViewResponseSerializer {

    public static final String PROPERTY_TOTAL_ROWS = "total_rows";

    public static final String PROPERTY_OFFSET = "offset";

    public static final String PROPERTY_ROWS = "rows";

    @Nonnull
    private final RowSerializer rowSerializer;

    public ViewResponseSerializer(@Nonnull RowSerializer rowSerializer) {
        this.rowSerializer = rowSerializer;
    }

    public <K, V> void serialize(@Nonnull ViewResponse<K, V, ?> viewResponse,
            @Nonnull JacksonSerializer<? super K> keySerializer,
            @Nonnull JacksonSerializer<? super V> valueSerializer, @Nonnull OutputStream out) throws IOException {
        JsonFactory jsonFactory = JacksonSupport.getJsonFactory();
        JsonGenerator generator = jsonFactory.createJsonGenerator(out, JsonEncoding.UTF8);

        generator.writeStartObject();

        generator.writeNumberField(PROPERTY_TOTAL_ROWS, viewResponse.getTotalRows());
        generator.writeNumberField(PROPERTY_OFFSET, viewResponse.getOffset());

        //Now the rows
        generator.writeFieldName(PROPERTY_ROWS);
        generator.writeStartArray();

        for (Row<K, V, ?> row : viewResponse.getRows()) {
            rowSerializer.serialize(row, keySerializer, valueSerializer, generator);
        }

        generator.writeEndArray();

        generator.writeEndObject();
        generator.close();
    }

    @Nonnull
    public <K, V> ViewResponse<K, V, Void> deserialize(@Nonnull JacksonSerializer<? super K> keySerializer,
            @Nonnull JacksonSerializer<? super V> valueSerializer, @Nonnull InputStream in)
            throws IOException, InvalidTypeException {
        return deserialize(keySerializer, valueSerializer, null, in);
    }

    public <K, V, D> ViewResponse<K, V, D> deserialize(@Nonnull JacksonSerializer<? super K> keySerializer,
            @Nonnull JacksonSerializer<? super V> valueSerializer,
            @Nullable JacksonSerializer<? extends D> documentSerializer, @Nonnull InputStream in)
            throws IOException, InvalidTypeException {
        JsonFactory jsonFactory = JacksonSupport.getJsonFactory();
        JsonParser parser = jsonFactory.createJsonParser(in);

        JacksonParserWrapper parserWrapper = new JacksonParserWrapper(parser);
        parserWrapper.nextToken(JsonToken.START_OBJECT);

        parserWrapper.nextToken(JsonToken.FIELD_NAME);
        //If reduced, no total rows and no offset are availlable!

        String fieldName = parser.getText();

        int totalRows = -1;
        int offset = -1;
        while (!fieldName.equals(PROPERTY_ROWS)) {
            if (fieldName.equals(PROPERTY_TOTAL_ROWS)) {
                parserWrapper.nextToken(JsonToken.VALUE_NUMBER_INT);
                totalRows = parser.getIntValue();
            }

            if (fieldName.equals(PROPERTY_OFFSET)) {
                parserWrapper.nextToken(JsonToken.VALUE_NUMBER_INT);
                offset = parser.getIntValue();
            }

            parserWrapper.nextToken(JsonToken.FIELD_NAME);
            fieldName = parser.getText();
        }

        //Now the rows...
        parserWrapper.nextToken(JsonToken.START_ARRAY);

        List<Row<K, V, D>> deserialized = new ArrayList<>();
        while (parser.nextToken() != JsonToken.END_ARRAY) {
            Row<K, V, D> deserializedRow = rowSerializer.deserialize(keySerializer, valueSerializer,
                    documentSerializer, parser);
            deserialized.add(deserializedRow);
        }

        return new ViewResponse<>(totalRows, offset, deserialized);
    }
}