JSON to SQL

Composite.scala

package models

import scala.collection.JavaConversions.asScalaIterator
import com.fasterxml.jackson.annotation.JsonSubTypes
import com.fasterxml.jackson.annotation.JsonTypeInfo
import com.fasterxml.jackson.databind.JsonNode
import com.fasterxml.jackson.databind.ObjectMapper

object Processor {
  val mapper: ObjectMapper = new ObjectMapper();
  def parseSql(str: String) = {

    def processOper(node: JsonNode) = {
      node.path("oper").asText() match {
        case "eq" => "="
        case "lteq" => ">="
        case "lt" => ">"
        case "steq" => "<="
        case "st" => "<"
      }
    }
    def process(node: JsonNode): String = {
      val currentNode = node
      currentNode.path("type").asText() match {
        case "and" =>
          " (" + currentNode.path("list").elements().map(element => process(element)).mkString(" AND ") + ") "
        case "or" =>
          " (" + currentNode.path("list").elements().map(element => process(element)).mkString(" OR ") + ") "
        case "text" =>
          currentNode.path("field").asText() + "='" + currentNode.path("value").asText + "'"
        case "number" =>
          currentNode.path("field").asText() + processOper(currentNode) + currentNode.path("value").asDouble 
        case "date" =>
          currentNode.path("field").asText() + processOper(currentNode) + " FROM_UNIXTIME(" + currentNode.path("value").asLong + ")"
      }
    }
    process(mapper.readTree(str))
  }
}

object App {
  def main(args: Array[String]) {
  
    val str = """
      {"type":"and","list":[
    	
    	{"type":"text","field":"alou","value":"val"},
    	{"type":"number","field":"alou","value":10,"oper":"eq"},
    	{"type":"date","field":"alou","value":223423840238,"oper":"eq"},
        {"type":"or","list":[
    	  {"type":"text","field":"alou","value":"val"},
    	  {"type":"text","field":"alou","value":"val"},
    	  {"type":"number","field":"alou","value":10,"oper":"eq"},
    	  {"type":"date","field":"alou","value":223423840238,"oper":"eq"},
    {"type":"or","list":[{"type":"text","field":"alou","value":"val"},{"type":"text","field":"alou","value":"val"}]}
        ]}
      ]}
      """
    println(Processor.parseSql(str))
  }
}