com.datastax.driver.dse.graph.DefaultGeometryDeserializer Maven / Gradle / Ivy

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A driver for DataStax Enterprise (DSE) and Apache Cassandra 1.2+ clusters that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol, supporting DSE-specific features such as geospatial types, DSE Graph and DSE authentication.

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/*
 * Copyright DataStax, Inc.
 *
 * This software can be used solely with DataStax Enterprise. Please consult the license at
 * http://www.datastax.com/terms/datastax-dse-driver-license-terms
 */
package com.datastax.driver.dse.graph;

import com.datastax.driver.dse.geometry.Geometry;
import com.datastax.driver.dse.geometry.LineString;
import com.datastax.driver.dse.geometry.Point;
import com.datastax.driver.dse.geometry.Polygon;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;

import java.io.IOException;

/**
 * Default deserializer used by the driver for geospatial types.
 * It deserializes such types into {@link Geometry} instances.
 * The actual subclass depends on the type being deserialized.
 */
class DefaultGeometryDeserializer extends StdDeserializer {

    private final Class geometryClass;

    DefaultGeometryDeserializer(Class geometryClass) {
        super(geometryClass);
        this.geometryClass = geometryClass;
    }

    @Override
    public T deserialize(JsonParser parser, DeserializationContext ctx) throws IOException {
        String wkt = parser.readValueAs(String.class);
        Geometry geometry;
        if (wkt.startsWith("POINT"))
            geometry = Point.fromWellKnownText(wkt);
        else if (wkt.startsWith("LINESTRING"))
            geometry = LineString.fromWellKnownText(wkt);
        else if (wkt.startsWith("POLYGON"))
            geometry = Polygon.fromWellKnownText(wkt);
        else
            throw new JsonParseException(parser, "Unknown geometry type: " + wkt);
        return geometryClass.cast(geometry);
    }

}