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/**
 * com.mckoi.database.interpret.ConstraintDef  09 Sep 2001
 *
 * Mckoi SQL Database ( http://www.mckoi.com/database )
 * Copyright (C) 2000, 2001, 2002  Diehl and Associates, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * Version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License Version 2 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * Version 2 along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Change Log:
 * 
 * 
 */

package com.mckoi.database.interpret;

import com.mckoi.database.*;
import java.util.ArrayList;

/**
 * Represents a constraint definition (description) for a table.
 *
 * @author Tobias Downer
 */

public final class ConstraintDef
            implements java.io.Serializable, StatementTreeObject, Cloneable {

  static final long serialVersionUID = -6648793780645431100L;

  // ---------- Statics that represent the base types of constraints ----------

  /**
   * A PRIMARY_KEY constraint.  With this constraint, the 'column_list'
   * list contains the names of the columns in this table that are defined as
   * the primary key.  There may only be one primary key constraint per table.
   */
  public static final int PRIMARY_KEY = 1;

  /**
   * A UNIQUE constraint.  With this constraint, the 'column_list' list
   * contains the names of the columns in this table that must be unique.
   */
  public static final int UNIQUE      = 2;

  /**
   * A FOREIGN_KEY constraint.  With this constraint, the 'table_name' string
   * contains the name of the table that this is a foreign key for, the
   * 'column_list' list contains the list of foreign key columns, and
   * 'column_list2' optionally contains the referenced columns.
   */
  public static final int FOREIGN_KEY = 3;

  /**
   * A CHECK constraint.  With this constraint, the 'expression' object
   * contains the expression that must evaluate to true when adding a
   * column to the table.
   */
  public static final int CHECK       = 4;


  // The type of constraint (from types in DataTableConstraintDef)
  int type;

  // The name of the constraint or null if the constraint has no name (in
  // which case it must be given an auto generated unique name at some point).
  String name;

  // The Check Expression
  Expression check_expression;
  // The serializable plain check expression as originally parsed
  Expression original_check_expression;

  // The first column list
  ArrayList column_list;

  // The second column list
  ArrayList column_list2;

  // The name of the table if referenced.
  String reference_table_name;

  // The foreign key update rule
  String update_rule;

  // The foreign key delete rule
  String delete_rule;

  // Whether this constraint is deferred to when the transaction commits.
  // ( By default we are 'initially immediate deferrable' )
  short deferred = Transaction.INITIALLY_IMMEDIATE;

  public ConstraintDef() {
  }

  /**
   * Sets the name of the constraint.
   */
  public void setName(String name) {
    this.name = name;
  }

  /**
   * Sets object up for a primary key constraint.
   */
  public void setPrimaryKey(ArrayList list) {
    type = PRIMARY_KEY;
    column_list = list;
  }

  /**
   * Sets object up for a unique constraint.
   */
  public void setUnique(ArrayList list) {
    type = UNIQUE;
    column_list = list;
  }

  /**
   * Sets object up for a check constraint.
   */
  public void setCheck(Expression exp) {
    type = CHECK;
    check_expression = exp;
    try {
      original_check_expression = (Expression) exp.clone();
    }
    catch (CloneNotSupportedException e) {
      throw new Error(e.getMessage());
    }
  }

  /**
   * Sets object up for foreign key reference.
   */
  public void setForeignKey(String ref_table, ArrayList col_list,
                            ArrayList ref_col_list,
                            String delete_rule, String update_rule) {
    type = FOREIGN_KEY;
    reference_table_name = ref_table;
    column_list = col_list;
    column_list2 = ref_col_list;
    this.delete_rule = delete_rule;
    this.update_rule = update_rule;

//    System.out.println("ConstraintDef setting rules: " + delete_rule + ", " + update_rule);
  }

  /**
   * Sets that this constraint is initially deferred.
   */
  public void setInitiallyDeferred() {
    deferred = Transaction.INITIALLY_DEFERRED;
  }

  /**
   * Sets that this constraint is not deferrable.
   */
  public void setNotDeferrable() {
    deferred = Transaction.NOT_DEFERRABLE;
  }



  /**
   * Returns the first column list as a string array.
   */
  public String[] getColumnList() {
    return (String[]) column_list.toArray(new String[column_list.size()]);
  }

  /**
   * Returns the first column list as a string array.
   */
  public String[] getColumnList2() {
    return (String[]) column_list2.toArray(new String[column_list2.size()]);
  }

  /**
   * Returns the delete rule if this is a foreign key reference.
   */
  public String getDeleteRule() {
    return delete_rule;
  }

  /**
   * Returns the update rule if this is a foreign key reference.
   */
  public String getUpdateRule() {
    return update_rule;
  }


  // Implemented from StatementTreeObject
  public void prepareExpressions(ExpressionPreparer preparer)
                                                  throws DatabaseException {
    if (check_expression != null) {
      check_expression.prepare(preparer);
    }
  }

  public Object clone() throws CloneNotSupportedException {
    ConstraintDef v = (ConstraintDef) super.clone();
    if (check_expression != null) {
      v.check_expression = (Expression) check_expression.clone();
    }
    if (column_list != null) {
      v.column_list = (ArrayList) column_list.clone();
    }
    if (column_list2 != null) {
      v.column_list2 = (ArrayList) column_list2.clone();
    }
    return v;
  }

}