/*--------------------------------------------------------------------------
    *  Copyright 2007 utgenome.org
    *
    *  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.
   *--------------------------------------------------------------------------*/
  //--------------------------------------
  // BugReport Project
  //
  // Relation.java
  // Since: 2007/03/28
  //
  // $URL$ 
  // $Author$
  //--------------------------------------
  package org.utgenome.gwt.utgb.client.db;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.utgenome.gwt.utgb.client.UTGBClientException;
  import org.utgenome.gwt.utgb.client.db.datatype.BooleanType;
  import org.utgenome.gwt.utgb.client.db.datatype.DataType;
  import org.utgenome.gwt.utgb.client.db.datatype.DoubleType;
  import org.utgenome.gwt.utgb.client.db.datatype.IntegerType;
  import org.utgenome.gwt.utgb.client.db.datatype.PasswordType;
  import org.utgenome.gwt.utgb.client.db.datatype.StringType;
  import org.utgenome.gwt.utgb.client.db.datatype.TextType;
  import org.utgenome.gwt.utgb.client.util.JSONUtil;
  
  import com.google.gwt.json.client.JSONArray;
  import com.google.gwt.json.client.JSONObject;
  import com.google.gwt.json.client.JSONParser;
  import com.google.gwt.json.client.JSONValue;
  import com.google.gwt.user.client.rpc.IsSerializable;
  
  /**
   * A Relation holds one or more DataTypes and denotes their relationships. For
   * example, in relational databases, a table has a structure, e.g. (pid:integer,
   * name:string, address:string)
   * 
   * You can construct this structure as follows: <code>
   * Relation r = new Relation();
   * r.add("pid", new IntegerType());
   * r.add("name", new StringType());
   * r.add("address", new StringType());
   * </code>
   * 
   * JSON format example. <code>
   * {"relation":[["id", "integer"], ["name", "string"], ...]}
   * </code>
   * 
   * 
   * @author leo
   * 
   */
  public class Relation implements IsSerializable
  {
      /**
       * The following line specifies the content of the List (dataType). This
       * information is requried in the GWT compiler.
       * 
       */
      private List<DataType> dataTypeList = new ArrayList<DataType>();
  
      public Relation()
      {}
  
      public Relation(String jsonStr) throws UTGBClientException
      {
          JSONValue json = JSONParser.parse(jsonStr);
          parse(json.isObject());
      }
  
      public Relation(JSONObject jsonObj) throws UTGBClientException
      {
          parse(jsonObj);
      }
  
      private void parse(JSONObject jsonObj) throws UTGBClientException
      {
          if (jsonObj == null)
              throw new UTGBClientException("null json object");
  
          if (!jsonObj.containsKey("relation"))
              throw new UTGBClientException("no relation key found");
          JSONArray relationList = jsonObj.get("relation").isArray();
          for (int i = 0; i < relationList.size(); i++)
          {
              JSONArray dataTypePair = relationList.get(i).isArray();
             if (dataTypePair == null || dataTypePair.size() != 2)
                 throw new UTGBClientException("data type must be json array with two elements: "
                         + relationList.toString());
 
             String parameterName = JSONUtil.toStringValue(dataTypePair.get(0));
             String typeName = JSONUtil.toStringValue(dataTypePair.get(1));
 
             add(getDataType(parameterName, typeName));
         }
     }
 
     public static DataType getDataType(String parameterName, String typeName) throws UTGBClientException
     {
         if (typeName.equals("boolean"))
             return new BooleanType(parameterName);
         else if (typeName.equals("double"))
             return new DoubleType(parameterName);
         else if (typeName.equals("string"))
             return new StringType(parameterName);
         else if (typeName.equals("password"))
             return new PasswordType(parameterName);
         else if (typeName.equals("text"))
             return new TextType(parameterName);
         else if (typeName.equals("integer"))
             return new IntegerType(parameterName);
         else
             throw new UTGBClientException("unknown data type: " + typeName);
     }
 
     public void add(DataType dataType)
     {
         dataTypeList.add(dataType);
     }
 
     public DataType getDataType(int index)
     {
         return (DataType) dataTypeList.get(index);
     }
 
     public List<DataType> getDataTypeList()
     {
         return dataTypeList;
     }
 
     public String toString()
     {
         StringBuffer s = new StringBuffer();
         s.append("(");
         for (DataType dt : dataTypeList)
         {
             s.append(dt.toString());
             s.append(" ");
         }
         s.append(")");
         return s.toString();
     }
 
 }