package com.framedobjects.dashwell.db;



import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;

import java.util.TreeMap;



import com.framedobjects.dashwell.db.meta.MetaField;

import com.framedobjects.dashwell.db.meta.MetaRelation;

import com.framedobjects.dashwell.db.meta.MetaTable;



/**

 * This class is used to interact directly with the existing database schema.

 * 

 * @author Jens Richnow

 * 

 */

public abstract class DbSchema {



  DbConnection dbConn = null;

  ArrayList<MetaTable> tables = null;

  TreeMap tablesAndFields = null;

  TreeMap relations = new TreeMap();

  public abstract ArrayList<MetaTable> getTables();



  public ArrayList<MetaField> getFieldsForTable(String tableName) {

    ArrayList<MetaField> fields = null;

    if (tableName != null) {

    	fields = (ArrayList) tablesAndFields.get(tableName);

    }

    return fields;

  }



  public ArrayList<MetaRelation> getRelations() {

    ArrayList<MetaRelation> rels = new ArrayList<MetaRelation>();

    Collection coll = relations.values();

    Iterator iter = coll.iterator();

    while (iter.hasNext()) {

      rels.add((MetaRelation)iter.next());

    }

    return rels;

  }



  public void addRelation(MetaRelation relation) {

    if (relation != null

        && !this.relations.containsKey(relation.getQualifiedName())) {

      this.relations.put(relation.getQualifiedName(), relation);

    }

  }



  public void removeRelation(MetaRelation relation) {

    if (relation != null) {

      this.removeRelationByName(relation.getQualifiedName());

    }

  }



  public void removeRelationByName(String qualifiedName) {

    if (qualifiedName != null && this.relations.containsKey(qualifiedName)) {

      this.relations.remove(qualifiedName);

    }

  }

}