/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.hql.internal.ast;

import java.lang.reflect.Constructor;

import org.hibernate.hql.internal.antlr.HqlSqlTokenTypes;
import org.hibernate.hql.internal.ast.tree.AggregateNode;
import org.hibernate.hql.internal.ast.tree.BetweenOperatorNode;
import org.hibernate.hql.internal.ast.tree.BinaryArithmeticOperatorNode;
import org.hibernate.hql.internal.ast.tree.BinaryLogicOperatorNode;
import org.hibernate.hql.internal.ast.tree.BooleanLiteralNode;
import org.hibernate.hql.internal.ast.tree.CastFunctionNode;
import org.hibernate.hql.internal.ast.tree.NullNode;
import org.hibernate.hql.internal.ast.tree.SearchedCaseNode;
import org.hibernate.hql.internal.ast.tree.SimpleCaseNode;
import org.hibernate.hql.internal.ast.tree.CollectionFunction;
import org.hibernate.hql.internal.ast.tree.ConstructorNode;
import org.hibernate.hql.internal.ast.tree.CountNode;
import org.hibernate.hql.internal.ast.tree.DeleteStatement;
import org.hibernate.hql.internal.ast.tree.DotNode;
import org.hibernate.hql.internal.ast.tree.FromClause;
import org.hibernate.hql.internal.ast.tree.FromElement;
import org.hibernate.hql.internal.ast.tree.IdentNode;
import org.hibernate.hql.internal.ast.tree.ImpliedFromElement;
import org.hibernate.hql.internal.ast.tree.InLogicOperatorNode;
import org.hibernate.hql.internal.ast.tree.IndexNode;
import org.hibernate.hql.internal.ast.tree.InitializeableNode;
import org.hibernate.hql.internal.ast.tree.InsertStatement;
import org.hibernate.hql.internal.ast.tree.IntoClause;
import org.hibernate.hql.internal.ast.tree.IsNotNullLogicOperatorNode;
import org.hibernate.hql.internal.ast.tree.IsNullLogicOperatorNode;
import org.hibernate.hql.internal.ast.tree.JavaConstantNode;
import org.hibernate.hql.internal.ast.tree.LiteralNode;
import org.hibernate.hql.internal.ast.tree.MapEntryNode;
import org.hibernate.hql.internal.ast.tree.MapKeyNode;
import org.hibernate.hql.internal.ast.tree.MapValueNode;
import org.hibernate.hql.internal.ast.tree.MethodNode;
import org.hibernate.hql.internal.ast.tree.OrderByClause;
import org.hibernate.hql.internal.ast.tree.ParameterNode;
import org.hibernate.hql.internal.ast.tree.QueryNode;
import org.hibernate.hql.internal.ast.tree.ResultVariableRefNode;
import org.hibernate.hql.internal.ast.tree.SelectClause;
import org.hibernate.hql.internal.ast.tree.SelectExpressionImpl;
import org.hibernate.hql.internal.ast.tree.SessionFactoryAwareNode;
import org.hibernate.hql.internal.ast.tree.SqlFragment;
import org.hibernate.hql.internal.ast.tree.SqlNode;
import org.hibernate.hql.internal.ast.tree.UnaryArithmeticNode;
import org.hibernate.hql.internal.ast.tree.UnaryLogicOperatorNode;
import org.hibernate.hql.internal.ast.tree.UpdateStatement;

import antlr.ASTFactory;
import antlr.Token;
import antlr.collections.AST;

Custom AST factory the intermediate tree that causes ANTLR to create specialized
AST nodes, given the AST node type (from HqlSqlTokenTypes).   HqlSqlWalker registers
this factory with itself when it is initialized.
Author:
Joshua/**
 * Custom AST factory the intermediate tree that causes ANTLR to create specialized
 * AST nodes, given the AST node type (from HqlSqlTokenTypes).   HqlSqlWalker registers
 * this factory with itself when it is initialized.
 *
 * @author Joshua
 */
public class SqlASTFactory extends ASTFactory implements HqlSqlTokenTypes {
	private HqlSqlWalker walker;

	
Create factory with a specific mapping from token type
to Java AST node type.  Your subclasses of ASTFactory
can override and reuse the map stuff.
/**
	 * Create factory with a specific mapping from token type
	 * to Java AST node type.  Your subclasses of ASTFactory
	 * can override and reuse the map stuff.
	 */
	public SqlASTFactory(HqlSqlWalker walker) {
		super();
		this.walker = walker;
	}

	
Returns the class for a given token type (a.k.a. AST node type).
Params:
tokenType – The token type.
Returns:
Class - The AST node class to instantiate./**
	 * Returns the class for a given token type (a.k.a. AST node type).
	 *
	 * @param tokenType The token type.
	 *
	 * @return Class - The AST node class to instantiate.
	 */
	public Class getASTNodeType(int tokenType) {
		switch ( tokenType ) {
			case SELECT:
			case QUERY:
				return QueryNode.class;
			case UPDATE:
				return UpdateStatement.class;
			case DELETE:
				return DeleteStatement.class;
			case INSERT:
				return InsertStatement.class;
			case INTO:
				return IntoClause.class;
			case FROM:
				return FromClause.class;
			case FROM_FRAGMENT:
				return FromElement.class;
			case IMPLIED_FROM:
				return ImpliedFromElement.class;
			case DOT:
				return DotNode.class;
			case INDEX_OP:
				return IndexNode.class;
			// Alias references and identifiers use the same node class.
			case ALIAS_REF:
			case IDENT:
				return IdentNode.class;
			case RESULT_VARIABLE_REF:
				return ResultVariableRefNode.class;
			case SQL_TOKEN:
				return SqlFragment.class;
			case METHOD_CALL:
				return MethodNode.class;
			case CAST:
				return CastFunctionNode.class;
			case ELEMENTS:
			case INDICES:
				return CollectionFunction.class;
			case SELECT_CLAUSE:
				return SelectClause.class;
			case SELECT_EXPR:
				return SelectExpressionImpl.class;
			case AGGREGATE:
				return AggregateNode.class;
			case COUNT:
				return CountNode.class;
			case CONSTRUCTOR:
				return ConstructorNode.class;
			case NUM_INT:
			case NUM_FLOAT:
			case NUM_LONG:
			case NUM_DOUBLE:
			case NUM_BIG_INTEGER:
			case NUM_BIG_DECIMAL:
			case QUOTED_STRING:
				return LiteralNode.class;
			case TRUE:
			case FALSE:
				return BooleanLiteralNode.class;
			case JAVA_CONSTANT:
				return JavaConstantNode.class;
			case ORDER:
				return OrderByClause.class;
			case PLUS:
			case MINUS:
			case STAR:
			case DIV:
			case MOD:
				return BinaryArithmeticOperatorNode.class;
			case UNARY_MINUS:
			case UNARY_PLUS:
				return UnaryArithmeticNode.class;
			case CASE2:
				return SimpleCaseNode.class;
			case CASE:
				return SearchedCaseNode.class;
			case PARAM:
			case NAMED_PARAM:
				return ParameterNode.class;
			case EQ:
			case NE:
			case LT:
			case GT:
			case LE:
			case GE:
			case LIKE:
			case NOT_LIKE:
				return BinaryLogicOperatorNode.class;
			case IN:
			case NOT_IN:
				return InLogicOperatorNode.class;
			case BETWEEN:
			case NOT_BETWEEN:
				return BetweenOperatorNode.class;
			case IS_NULL:
				return IsNullLogicOperatorNode.class;
			case IS_NOT_NULL:
				return IsNotNullLogicOperatorNode.class;
			case EXISTS:
				return UnaryLogicOperatorNode.class;
			case KEY: {
				return MapKeyNode.class;
			}
			case VALUE: {
				return MapValueNode.class;
			}
			case ENTRY: {
				return MapEntryNode.class;
			}
			case NULL : {
				return NullNode.class;
			}
			default:
				return SqlNode.class;
		}
	}

	@SuppressWarnings("unchecked")
	protected AST createUsingCtor(Token token, String className) {
		Class c;
		AST t;
		try {
			c = Class.forName( className );
			Class[] tokenArgType = new Class[] {antlr.Token.class};
			Constructor ctor = c.getConstructor( tokenArgType );
			if ( ctor != null ) {
				t = (AST) ctor.newInstance( token );
				initializeSqlNode( t );
			}
			else {
				// just do the regular thing if you can't find the ctor
				// Your AST must have default ctor to use this.
				t = create( c );
			}
		}
		catch (Exception e) {
			throw new IllegalArgumentException( "Invalid class or can't make instance, " + className );
		}
		return t;
	}

	private void initializeSqlNode(AST t) {
		// Initialize SQL nodes here.
		if ( t instanceof InitializeableNode ) {
			InitializeableNode initializeableNode = (InitializeableNode) t;
			initializeableNode.initialize( walker );
		}
		if ( t instanceof SessionFactoryAwareNode ) {
			( (SessionFactoryAwareNode) t ).setSessionFactory( walker.getSessionFactoryHelper().getFactory() );
		}
	}

	
Actually instantiate the AST node.
Params:
c – The class to instantiate.
Returns:
The instantiated and initialized node./**
	 * Actually instantiate the AST node.
	 *
	 * @param c The class to instantiate.
	 *
	 * @return The instantiated and initialized node.
	 */
	protected AST create(Class c) {
		AST t;
		try {
			t = (AST) c.newInstance();
			initializeSqlNode( t );
		}
		catch (Exception e) {
			error( "Can't create AST Node " + c.getName() );
			return null;
		}
		return t;
	}

}