package org.msh.reports.query;


/**
 * Store temporary information about a join between two tables. This information is primarily
 * used when generating a SQL declaration where it's necessary to create join between tables.
 * <p/>
 * This join structure is similar to a tree, where the root table join represents the main
 * class in the SQL from declaration
 * 
 * @author Ricardo Memoria
 *
 */
public interface TableJoin {
	TableJoin select(String field);
	
	/**
	 * Add a join to the current table
	 * @param field is the field of the table to be joined with
	 * @param targetTable is the table to join with
	 * @return instance of the new {@link TableJoin} implementation
	 */
	TableJoin join(String field, String targetTable);
	
	/**
	 * Add a left join to the current table
	 * @param field is the field of the current table to be joined with
	 * @param targetTable is the table.field definition of the new table to join with
	 * @return is the instance of the new {@link TableJoin} implementation
	 */
	TableJoin leftJoin(String field, String targetTable);
	
	/**
	 * Get the alias of the table to be used in the SQL statement
	 * @return String value
	 */
	String getAlias();
	
	/**
	 * Change the alias of the table to be used in the SQL statement
	 * @param value the new table alias
	 */
	void setAlias(String value);
	
	
	/**
	 * Return the table name of this join
	 * @return String value
	 */
	String getTableName();
	
	/**
	 * Return the parent join of this table join
	 * @return instance of {@link TableJoin} implementation
	 */
	TableJoin getParentJoin();
}