whereparser.java

一个Java持久层类库

//$Id: WhereParser.java 7825 2005-08-10 20:23:55Z oneovthafew $
package org.hibernate.hql.classic;

import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;

import org.hibernate.MappingException;
import org.hibernate.QueryException;
import org.hibernate.engine.JoinSequence;
import org.hibernate.hql.QueryTranslator;
import org.hibernate.persister.collection.CollectionPropertyNames;
import org.hibernate.persister.entity.Queryable;
import org.hibernate.sql.InFragment;
import org.hibernate.type.EntityType;
import org.hibernate.type.LiteralType;
import org.hibernate.type.Type;
import org.hibernate.type.TypeFactory;
import org.hibernate.util.ReflectHelper;
import org.hibernate.util.StringHelper;

/**
 * Parses the where clause of a hibernate query and translates it to an
 * SQL where clause.
 */

// We should reengineer this class so that, rather than the current ad -
// hoc linear approach to processing a stream of tokens, we instead
// build up a tree of expressions.

// We would probably refactor to have LogicParser (builds a tree of simple
// expressions connected by and, or, not), ExpressionParser (translates
// from OO terms like foo, foo.Bar, foo.Bar.Baz to SQL terms like
// FOOS.ID, FOOS.BAR_ID, etc) and PathExpressionParser (which does much
// the same thing it does now)

public class WhereParser implements Parser {

	private final PathExpressionParser pathExpressionParser;

	{
		pathExpressionParser = new PathExpressionParser();
		pathExpressionParser.setUseThetaStyleJoin( true ); //Need this, since join condition can appear inside parens!
	}

	private static final Set EXPRESSION_TERMINATORS = new HashSet();   //tokens that close a sub expression
	private static final Set EXPRESSION_OPENERS = new HashSet();       //tokens that open a sub expression
	private static final Set BOOLEAN_OPERATORS = new HashSet();        //tokens that would indicate a sub expression is a boolean expression
	private static final Map NEGATIONS = new HashMap();

	static {
		EXPRESSION_TERMINATORS.add( "and" );
		EXPRESSION_TERMINATORS.add( "or" );
		EXPRESSION_TERMINATORS.add( ")" );
		//expressionTerminators.add(","); // deliberately excluded

		EXPRESSION_OPENERS.add( "and" );
		EXPRESSION_OPENERS.add( "or" );
		EXPRESSION_OPENERS.add( "(" );
		//expressionOpeners.add(","); // deliberately excluded

		BOOLEAN_OPERATORS.add( "<" );
		BOOLEAN_OPERATORS.add( "=" );
		BOOLEAN_OPERATORS.add( ">" );
		BOOLEAN_OPERATORS.add( "#" );
		BOOLEAN_OPERATORS.add( "~" );
		BOOLEAN_OPERATORS.add( "like" );
		BOOLEAN_OPERATORS.add( "ilike" );
		BOOLEAN_OPERATORS.add( "regexp" );
		BOOLEAN_OPERATORS.add( "rlike" );
		BOOLEAN_OPERATORS.add( "is" );
		BOOLEAN_OPERATORS.add( "in" );
		BOOLEAN_OPERATORS.add( "any" );
		BOOLEAN_OPERATORS.add( "some" );
		BOOLEAN_OPERATORS.add( "all" );
		BOOLEAN_OPERATORS.add( "exists" );
		BOOLEAN_OPERATORS.add( "between" );
		BOOLEAN_OPERATORS.add( "<=" );
		BOOLEAN_OPERATORS.add( ">=" );
		BOOLEAN_OPERATORS.add( "=>" );
		BOOLEAN_OPERATORS.add( "=<" );
		BOOLEAN_OPERATORS.add( "!=" );
		BOOLEAN_OPERATORS.add( "<>" );
		BOOLEAN_OPERATORS.add( "!#" );
		BOOLEAN_OPERATORS.add( "!~" );
		BOOLEAN_OPERATORS.add( "!<" );
		BOOLEAN_OPERATORS.add( "!>" );
		BOOLEAN_OPERATORS.add( "is not" );
		BOOLEAN_OPERATORS.add( "not like" );
		BOOLEAN_OPERATORS.add( "not ilike" );
		BOOLEAN_OPERATORS.add( "not regexp" );
		BOOLEAN_OPERATORS.add( "not rlike" );
		BOOLEAN_OPERATORS.add( "not in" );
		BOOLEAN_OPERATORS.add( "not between" );
		BOOLEAN_OPERATORS.add( "not exists" );

		NEGATIONS.put( "and", "or" );
		NEGATIONS.put( "or", "and" );
		NEGATIONS.put( "<", ">=" );
		NEGATIONS.put( "=", "<>" );
		NEGATIONS.put( ">", "<=" );
		NEGATIONS.put( "#", "!#" );
		NEGATIONS.put( "~", "!~" );
		NEGATIONS.put( "like", "not like" );
		NEGATIONS.put( "ilike", "not ilike" );
		NEGATIONS.put( "regexp", "not regexp" );
		NEGATIONS.put( "rlike", "not rlike" );
		NEGATIONS.put( "is", "is not" );
		NEGATIONS.put( "in", "not in" );
		NEGATIONS.put( "exists", "not exists" );
		NEGATIONS.put( "between", "not between" );
		NEGATIONS.put( "<=", ">" );
		NEGATIONS.put( ">=", "<" );
		NEGATIONS.put( "=>", "<" );
		NEGATIONS.put( "=<", ">" );
		NEGATIONS.put( "!=", "=" );
		NEGATIONS.put( "<>", "=" );
		NEGATIONS.put( "!#", "#" );
		NEGATIONS.put( "!~", "~" );
		NEGATIONS.put( "!<", "<" );
		NEGATIONS.put( "!>", ">" );
		NEGATIONS.put( "is not", "is" );
		NEGATIONS.put( "not like", "like" );
		NEGATIONS.put( "not ilike", "ilike" );
		NEGATIONS.put( "not regexp", "regexp" );
		NEGATIONS.put( "not rlike", "rlike" );
		NEGATIONS.put( "not in", "in" );
		NEGATIONS.put( "not between", "between" );
		NEGATIONS.put( "not exists", "exists" );

	}
	// Handles things like:
	// a and b or c
	// a and ( b or c )
	// not a and not b
	// not ( a and b )
	// x between y and z            (overloaded "and")
	// x in ( a, b, c )             (overloaded brackets)
	// not not a
	// a is not null                (overloaded "not")
	// etc......
	// and expressions like
	// foo = bar                    (maps to: foo.id = bar.id)
	// foo.Bar = 'foo'              (maps to: foo.bar = 'foo')
	// foo.Bar.Baz = 1.0            (maps to: foo.bar = bar.id and bar.baz = 1.0)
	// 1.0 = foo.Bar.Baz            (maps to: bar.baz = 1.0 and foo.Bar = bar.id)
	// foo.Bar.Baz = a.B.C          (maps to: bar.Baz = b.C and foo.Bar = bar.id and a.B = b.id)
	// foo.Bar.Baz + a.B.C          (maps to: bar.Baz + b.C and foo.Bar = bar.id and a.B = b.id)
	// ( foo.Bar.Baz + 1.0 ) < 2.0  (maps to: ( bar.Baz + 1.0 ) < 2.0 and foo.Bar = bar.id)

	private boolean betweenSpecialCase = false;       //Inside a BETWEEN ... AND ... expression
	private boolean negated = false;

	private boolean inSubselect = false;
	private int bracketsSinceSelect = 0;
	private StringBuffer subselect;

	private boolean expectingPathContinuation = false;
	private int expectingIndex = 0;

	// The following variables are stacks that keep information about each subexpression
	// in the list of nested subexpressions we are currently processing.

	private LinkedList nots = new LinkedList();           //were an odd or even number of NOTs encountered
	private LinkedList joins = new LinkedList();          //the join string built up by compound paths inside this expression
	private LinkedList booleanTests = new LinkedList();   //a flag indicating if the subexpression is known to be boolean

	private String getElementName(PathExpressionParser.CollectionElement element, QueryTranslatorImpl q) throws QueryException {
		String name;
		if ( element.isOneToMany ) {
			name = element.alias;
		}
		else {
			Type type = element.elementType;
			if ( type.isEntityType() ) { //ie. a many-to-many
				String entityName = ( ( EntityType ) type ).getAssociatedEntityName();
				name = pathExpressionParser.continueFromManyToMany( entityName, element.elementColumns, q );
			}
			else {
				throw new QueryException( "illegally dereferenced collection element" );
			}
		}
		return name;
	}

	public void token(String token, QueryTranslatorImpl q) throws QueryException {

		String lcToken = token.toLowerCase();

		//Cope with [,]
		if ( token.equals( "[" ) && !expectingPathContinuation ) {
			expectingPathContinuation = false;
			if ( expectingIndex == 0 ) throw new QueryException( "unexpected [" );
			return;
		}
		else if ( token.equals( "]" ) ) {
			expectingIndex--;
			expectingPathContinuation = true;
			return;
		}

		//Cope with a continued path expression (ie. ].baz)
		if ( expectingPathContinuation ) {
			boolean pathExpressionContinuesFurther = continuePathExpression( token, q );
			if ( pathExpressionContinuesFurther ) return; //NOTE: early return
		}

		//Cope with a subselect
		if ( !inSubselect && ( lcToken.equals( "select" ) || lcToken.equals( "from" ) ) ) {
			inSubselect = true;
			subselect = new StringBuffer( 20 );
		}
		if ( inSubselect && token.equals( ")" ) ) {
			bracketsSinceSelect--;

			if ( bracketsSinceSelect == -1 ) {
				QueryTranslatorImpl subq = new QueryTranslatorImpl(
				        subselect.toString(),
						q.getEnabledFilters(),
						q.getFactory()
				);
				try {
					subq.compile( q );
				}
				catch ( MappingException me ) {
					throw new QueryException( "MappingException occurred compiling subquery", me );
				}
				appendToken( q, subq.getSQLString() );
				inSubselect = false;
				bracketsSinceSelect = 0;
			}
		}
		if ( inSubselect ) {
			if ( token.equals( "(" ) ) bracketsSinceSelect++;
			subselect.append( token ).append( ' ' );
			return;
		}

		//Cope with special cases of AND, NOT, ()
		specialCasesBefore( lcToken );

		//Close extra brackets we opened
		if ( !betweenSpecialCase && EXPRESSION_TERMINATORS.contains( lcToken ) ) {
			closeExpression( q, lcToken );