//$Id: FromParser.java 5699 2005-02-13 11:50:11Z oneovthafew $
package org.hibernate.hql.classic;
import org.hibernate.QueryException;
import org.hibernate.hql.QueryTranslator;
import org.hibernate.persister.entity.Queryable;
import org.hibernate.sql.JoinFragment;
import java.util.HashMap;
import java.util.Map;
/**
* Parses the from clause of a hibernate query, looking for tables and
* aliases for the SQL query.
*/
public class FromParser implements Parser {
private final PathExpressionParser peParser = new FromPathExpressionParser();
private String entityName;
private String alias;
private boolean afterIn;
private boolean afterAs;
private boolean afterClass;
private boolean expectingJoin;
private boolean expectingIn;
private boolean expectingAs;
private boolean afterJoinType;
private int joinType;
private boolean afterFetch;
private static final int NONE = -666;
private static final Map JOIN_TYPES = new HashMap();
static {
JOIN_TYPES.put( "left", new Integer( JoinFragment.LEFT_OUTER_JOIN ) );
JOIN_TYPES.put( "right", new Integer( JoinFragment.RIGHT_OUTER_JOIN ) );
JOIN_TYPES.put( "full", new Integer( JoinFragment.FULL_JOIN ) );
JOIN_TYPES.put( "inner", new Integer( JoinFragment.INNER_JOIN ) );
}
public void token(String token, QueryTranslatorImpl q) throws QueryException {
// start by looking for HQL keywords...
String lcToken = token.toLowerCase();
if ( lcToken.equals( "," ) ) {
if ( !( expectingJoin | expectingAs ) ) throw new QueryException( "unexpected token: ," );
expectingJoin = false;
expectingAs = false;
}
else if ( lcToken.equals( "join" ) ) {
if ( !afterJoinType ) {
if ( !( expectingJoin | expectingAs ) ) throw new QueryException( "unexpected token: join" );
// inner joins can be abbreviated to 'join'
joinType = JoinFragment.INNER_JOIN;
expectingJoin = false;
expectingAs = false;
}
else {
afterJoinType = false;
}
}
else if ( lcToken.equals( "fetch" ) ) {
if ( q.isShallowQuery() ) throw new QueryException( QueryTranslator.ERROR_CANNOT_FETCH_WITH_ITERATE );
if ( joinType == NONE ) throw new QueryException( "unexpected token: fetch" );
if ( joinType == JoinFragment.FULL_JOIN || joinType == JoinFragment.RIGHT_OUTER_JOIN ) {
throw new QueryException( "fetch may only be used with inner join or left outer join" );
}
afterFetch = true;
}
else if ( lcToken.equals( "outer" ) ) {
// 'outer' is optional and is ignored
if ( !afterJoinType ||
( joinType != JoinFragment.LEFT_OUTER_JOIN && joinType != JoinFragment.RIGHT_OUTER_JOIN )
) {
throw new QueryException( "unexpected token: outer" );
}
}
else if ( JOIN_TYPES.containsKey( lcToken ) ) {
if ( !( expectingJoin | expectingAs ) ) throw new QueryException( "unexpected token: " + token );
joinType = ( ( Integer ) JOIN_TYPES.get( lcToken ) ).intValue();
afterJoinType = true;
expectingJoin = false;
expectingAs = false;
}
else if ( lcToken.equals( "class" ) ) {
if ( !afterIn ) throw new QueryException( "unexpected token: class" );
if ( joinType != NONE ) throw new QueryException( "outer or full join must be followed by path expression" );
afterClass = true;
}
else if ( lcToken.equals( "in" ) ) {
if ( !expectingIn ) throw new QueryException( "unexpected token: in" );
afterIn = true;
expectingIn = false;
}
else if ( lcToken.equals( "as" ) ) {
if ( !expectingAs ) throw new QueryException( "unexpected token: as" );
afterAs = true;
expectingAs = false;
}
else {
if ( afterJoinType ) throw new QueryException( "join expected: " + token );
if ( expectingJoin ) throw new QueryException( "unexpected token: " + token );
if ( expectingIn ) throw new QueryException( "in expected: " + token );
// now anything that is not a HQL keyword
if ( afterAs || expectingAs ) {
// (AS is always optional, for consistency with SQL/OQL)
// process the "new" HQL style where aliases are assigned
// _after_ the class name or path expression ie. using
// the AS construction
if ( entityName != null ) {
q.setAliasName( token, entityName );
}
else {
throw new QueryException( "unexpected: as " + token );
}
afterAs = false;
expectingJoin = true;
expectingAs = false;
entityName = null;
}
else if ( afterIn ) {
// process the "old" HQL style where aliases appear _first_
// ie. using the IN or IN CLASS constructions
if ( alias == null ) throw new QueryException( "alias not specified for: " + token );
if ( joinType != NONE ) throw new QueryException( "outer or full join must be followed by path expression" );
if ( afterClass ) {
// treat it as a classname
Queryable p = q.getEntityPersisterUsingImports( token );
if ( p == null ) throw new QueryException( "persister not found: " + token );
q.addFromClass( alias, p );
}
else {
// treat it as a path expression
peParser.setJoinType( JoinFragment.INNER_JOIN );
peParser.setUseThetaStyleJoin( true );
ParserHelper.parse( peParser, q.unalias( token ), ParserHelper.PATH_SEPARATORS, q );
if ( !peParser.isCollectionValued() ) throw new QueryException( "path expression did not resolve to collection: " + token );
String nm = peParser.addFromCollection( q );
q.setAliasName( alias, nm );
}
alias = null;
afterIn = false;
afterClass = false;
expectingJoin = true;
}
else {
// handle a path expression or class name that
// appears at the start, in the "new" HQL
// style or an alias that appears at the start
// in the "old" HQL style
Queryable p = q.getEntityPersisterUsingImports( token );
if ( p != null ) {
// starts with the name of a mapped class (new style)
if ( joinType != NONE ) throw new QueryException( "outer or full join must be followed by path expression" );
entityName = q.createNameFor( p.getEntityName() );
q.addFromClass( entityName, p );
expectingAs = true;
}
else if ( token.indexOf( '.' ) < 0 ) {
// starts with an alias (old style)
// semi-bad thing about this: can't re-alias another alias.....
alias = token;
expectingIn = true;
}
else {
// starts with a path expression (new style)
// force HQL style: from Person p inner join p.cars c
//if (joinType==NONE) throw new QueryException("path expression must be preceded by full, left, right or inner join");
//allow ODMG OQL style: from Person p, p.cars c
if ( joinType != NONE ) {
peParser.setJoinType( joinType );
}
else {
peParser.setJoinType( JoinFragment.INNER_JOIN );
}
peParser.setUseThetaStyleJoin( q.isSubquery() );
ParserHelper.parse( peParser, q.unalias( token ), ParserHelper.PATH_SEPARATORS, q );
entityName = peParser.addFromAssociation( q );
joinType = NONE;
peParser.setJoinType( JoinFragment.INNER_JOIN );
if ( afterFetch ) {
peParser.fetch( q, entityName );
afterFetch = false;
}
expectingAs = true;
}
}
}
}
public void start(QueryTranslatorImpl q) {
entityName = null;
alias = null;
afterIn = false;
afterAs = false;
afterClass = false;
expectingJoin = false;
expectingIn = false;
expectingAs = false;
joinType = NONE;
}
public void end(QueryTranslatorImpl q) {
}
}
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