/*
 *                 Sun Public License Notice
 *
 * The contents of this file are subject to the Sun Public License
 * Version 1.0 (the "License"). You may not use this file except in
 * compliance with the License. A copy of the License is available at
 * http://www.sun.com/
 *
 * The Original Code is NetBeans. The Initial Developer of the Original
 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2004 Sun
 * Microsystems, Inc. All Rights Reserved.
 */
package org.netbeans.spi.java.queries;

import org.openide.filesystems.FileObject;

/**
 * Permits providers to return source level of Java source file.
 * 

 * A default implementation is registered by the
 * org.netbeans.modules.java.project module which looks up the
 * project corresponding to the file (if any) and checks whether that
 * project has an implementation of this interface in its lookup. If so, it
 * delegates to that implementation. Therefore it is not generally necessary
 * for a project type provider to register its own global implementation of
 * this query, if it depends on the Java Project module and uses this style.
 * 
 * @see org.netbeans.api.java.queries.SourceLevelQuery
 * @see org.netbeans.api.queries.FileOwnerQuery
 * @see org.netbeans.api.project.Project#getLookup
 * @author David Konecny
 * @since org.netbeans.api.java/1 1.5
 */
public interface SourceLevelQueryImplementation {

    /**
     * Returns source level of the given Java file. For acceptable return values
     * see the documentation of -source command line switch of 
     * javac compiler .
     * @param javaFile Java source file in question
     * @return source level of the Java file, e.g. "1.3", "1.4" or "1.5", or
     *    null if it is not known
     */
    public String getSourceLevel(FileObject javaFile);

}