org.hibernate.hql.internal.QuerySplitter Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, 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 Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*
*/
package org.hibernate.hql.internal;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;
import org.hibernate.MappingException;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.hql.internal.classic.ParserHelper;
import org.hibernate.internal.CoreLogging;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.internal.util.StringHelper;
/**
* Provides query splitting methods, which were originally in QueryTranslator.
*
* @author josh
*/
public final class QuerySplitter {
private static final CoreMessageLogger LOG = CoreLogging.messageLogger( QuerySplitter.class );
private static final Set BEFORE_CLASS_TOKENS = new HashSet();
private static final Set NOT_AFTER_CLASS_TOKENS = new HashSet();
static {
BEFORE_CLASS_TOKENS.add( "from" );
BEFORE_CLASS_TOKENS.add( "delete" );
BEFORE_CLASS_TOKENS.add( "update" );
//beforeClassTokens.add("new"); DEFINITELY DON'T HAVE THIS!!
BEFORE_CLASS_TOKENS.add( "," );
NOT_AFTER_CLASS_TOKENS.add( "in" );
//notAfterClassTokens.add(",");
NOT_AFTER_CLASS_TOKENS.add( "from" );
NOT_AFTER_CLASS_TOKENS.add( ")" );
}
/**
* Private empty constructor.
* (or else checkstyle says: 'warning: Utility classes should not have a public or default constructor.')
*/
private QuerySplitter() {
}
/**
* Handle Hibernate "implicit" polymorphism, by translating the query string into
* several "concrete" queries against mapped classes.
*/
public static String[] concreteQueries(String query, SessionFactoryImplementor factory) throws MappingException {
//scan the query string for class names appearing in the from clause and replace
//with all persistent implementors of the class/interface, returning multiple
//query strings (make sure we don't pick up a class in the select clause!)
//TODO: this is one of the ugliest and most fragile pieces of code in Hibernate....
String[] tokens = StringHelper.split( StringHelper.WHITESPACE + "(),", query, true );
if ( tokens.length == 0 ) {
// just especially for the trivial collection filter
return new String[] { query };
}
ArrayList placeholders = new ArrayList();
ArrayList replacements = new ArrayList();
StringBuilder templateQuery = new StringBuilder( 40 );
int start = getStartingPositionFor( tokens, templateQuery );
int count = 0;
String next;
String last = tokens[start - 1].toLowerCase();
for ( int i = start; i < tokens.length; i++ ) {
String token = tokens[i];
if ( ParserHelper.isWhitespace( token ) ) {
templateQuery.append( token );
continue;
}
next = nextNonWhite( tokens, i ).toLowerCase();
boolean process = isJavaIdentifier( token ) &&
isPossiblyClassName( last, next );
last = token.toLowerCase();
if ( process ) {
String importedClassName = getImportedClass( token, factory );
if ( importedClassName != null ) {
String[] implementors = factory.getImplementors( importedClassName );
token = "$clazz" + count++ + "$";
if ( implementors != null ) {
placeholders.add( token );
replacements.add( implementors );
}
}
}
templateQuery.append( token );
}
String[] results = StringHelper.multiply(
templateQuery.toString(),
placeholders.iterator(),
replacements.iterator()
);
if ( results.length == 0 ) {
LOG.noPersistentClassesFound( query );
}
return results;
}
private static String nextNonWhite(String[] tokens, int start) {
for ( int i = start + 1; i < tokens.length; i++ ) {
if ( !ParserHelper.isWhitespace( tokens[i] ) ) {
return tokens[i];
}
}
return tokens[tokens.length - 1];
}
private static int getStartingPositionFor(String[] tokens, StringBuilder templateQuery) {
templateQuery.append( tokens[0] );
if ( !"select".equals( tokens[0].toLowerCase() ) ) {
return 1;
}
// select-range is terminated by declaration of "from"
for ( int i = 1; i < tokens.length; i++ ) {
if ( "from".equals( tokens[i].toLowerCase() ) ) {
return i;
}
templateQuery.append( tokens[i] );
}
return tokens.length;
}
private static boolean isPossiblyClassName(String last, String next) {
return "class".equals( last )
|| ( BEFORE_CLASS_TOKENS.contains( last ) && !NOT_AFTER_CLASS_TOKENS.contains( next ) );
}
private static boolean isJavaIdentifier(String token) {
return Character.isJavaIdentifierStart( token.charAt( 0 ) );
}
public static String getImportedClass(String name, SessionFactoryImplementor factory) {
return factory.getImportedClassName( name );
}
}