/*
 *                 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 java.net.URL;
import org.netbeans.api.java.queries.SourceForBinaryQuery;
import org.openide.filesystems.FileObject;

// XXX add a listener to changes in result

/**
 * Information about where Java sources corresponding to binaries
 * (classfiles) can be found.
 * 

 * A default implementation is registered by the
 * org.netbeans.modules.java.project module which looks up the
 * project corresponding to the file (if any; jar-protocol URLs
 * actually check the owner of the JAR file itself) 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.
 * 
 * 

 * 

 * Note that if you supply a SourceForBinaryQueryImplementation
 * corresponding to an entry in a {@link org.netbeans.spi.java.classpath.ClassPathProvider} for some source
 * files, there needs to be a {@link org.netbeans.spi.java.classpath.ClassPathProvider} for the sources
 * used as dependencies as well. Otherwise code completion will not work well;
 * the current parser database creation strategy uses the following search order
 * when deciding what to parse for a binary classpath element:
 * 
 * 

 * 
The sources returned by SourceForBinaryQueryImplementation,
 *     if these have at least a bootclasspath specified as well by some
 *     {@link org.netbeans.spi.java.classpath.ClassPathProvider}.
 * 
Compiled classes mixed into the "source" directory, if there are any.
 * 
Compiled classes in the binary classpath element.
 * 
 * 
 * @see org.netbeans.api.java.queries.SourceForBinaryQuery
 * @see org.netbeans.api.queries.FileOwnerQuery
 * @see org.netbeans.api.project.Project#getLookup
 * @since org.netbeans.api.java/1 1.4
 */
public interface SourceForBinaryQueryImplementation {

    /**
     * Returns the source root(s) for a given binary root.
     * 

     * Any absolute URL may be used but typically it will use the file
     * protocol for directory entries and jar protocol for JAR entries
     * (e.g. jar:file:/tmp/foo.jar!/).
     * 
     * @param binaryRoot the class path root of Java class files
     * @return a result object encapsulating the answer or null if the binaryRoot is not recognized
     */
    public SourceForBinaryQuery.Result findSourceRoots(URL binaryRoot);
    
}