Bug 31473 Search Engine should not search in working copies that aren't on the build path
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/JavaUI.java
public static IDocumentProvider getDocumentProvider() {
		return JavaPlugin.getDefault().getCompilationUnitDocumentProvider();
	}
		
	/**
	 * Sets the Javadoc location for an archive with the given path.
	 * 
	 * @param archivePath the path of the library; this can be an workspace path
	 * or an external path in case of an external library.
	 * @param url The Javadoc location to set. This location should contain index.html and
	 * a file 'package-list'. <code>null</code> clears the current documentation
	 * location.
	 * 
	 * @since 2.0
	 */
	public static void setLibraryJavadocLocation(IPath archivePath, URL url) {
		JavaDocLocations.setLibraryJavadocLocation(archivePath, url);
	}
	/**
	 * Returns the Javadoc location for an archive or <code>null</code> if no
	 * location is available.
	 * 
	 * @param archivePath the path of the library. This can be an workspace path
	 * or an external path in case of an external library.
	 * 
	 * @since 2.0
	 */	
	public static URL getLibraryJavadocLocation(IPath archivePath) {
		return JavaDocLocations.getLibraryJavadocLocation(archivePath);
	}