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Home » bsf-src-2.4.0 » org.apache.bsf.debug » [javadoc | source]
org.apache.bsf.debug
public interface: BSFDebugManager [javadoc | source]

All Implemented Interfaces:
    Remote

All Known Implementing Classes:
    BSFDebugManagerImpl, DebugManagerStub

Debug Manager. This is a service for remote debuggers to gain access to remote debugging services on language engines. Currently, there is only one debugger supported per engine. However, multiple debuggers may register for different engines. There may be more than one engine per language given than more than one BSFManager can be instanciated within a Java virtual machine. Each debugger (instance of BSFDebugger) should first register itself to a debug manager running in the Java virtual machine in which debugging is intended. A debugger registers for a specific language, such as JavaScript. As a consequence of registration, the debugger will be notified of already existing engines as well as any future creation or termination of engines for the relevant language. Upon this notification, the debugger can ask the engine for its language-specific debugging interface and then register the debugger callbacks for debugging events. See org.apache.bsf.debug.jsdi.Callbacks for the JavaScript example. The debugging framework works on the concept of documents and breakpoints. A document is basically a container for scripts (be them functions, expressions, or actual scripts). These scripts are subsets of the document. Documents are declared to the BSFEngine when evaluating or executing some scripts. Scripts are defined as a range, either line or character range in their document. Correspondingly, breakpoints can be set at lines or offsets in a document. The line numbers and offsets are global numbers with respect to the entire document. So for instance, in a JSP with JavaScript, the document is the JSP file. The scripts are the tags containing JavaScript code. The Jasper compiler extracts the scripts from the JSP and produces a Servlet that will provide these scripts to the BSF JavaScript engine at execution time. Each of these scripts start at a given line, offsets are not supported. Breakpoints can therefore be set at lines belonging to these JavaScript scripts, considering line numbers at the document level, that is, the entire JSP file.
Method from org.apache.bsf.debug.BSFDebugManager Summary:
getLangFromFilename,   isLanguageRegistered,   placeBreakpointAtLine,   placeBreakpointAtOffset,   registerDebugger,   removeBreakpoint,   setEntryExit,   supportBreakpointAtLine,   supportBreakpointAtOffset,   unregisterDebugger
Method from org.apache.bsf.debug.BSFDebugManager Detail:
 public String getLangFromFilename(String fileName) throws RemoteException
    Determine the language of a script file by looking at the file
extension.
 public boolean isLanguageRegistered(String lang) throws RemoteException
    Determine whether a language is registered.
 public  void placeBreakpointAtLine(int bpid,
    String docname,
    int lineno) throws RemoteException
    Breakpoints are placed within documents either at a specific line
or offset. While breakpoints can be set at lines and offsets in
the same document, there is no conversions between lines and offsets.
Some engines may support only offsets or only lines and therefore
some breakpoints may be ignored.

Placing a breakpoint is local to a debugger connection.
In other words, breakpoints set by other debuggers are not visible
to a given debugger.

Breakpoints are given identifiers so to make easier for debuggers
to manipulate breakpoints. Identifiers are allocated by the debugger;
they must be unique for the entire session between that debugger
and the debug manager.
 public  void placeBreakpointAtOffset(int bpid,
    String docname,
    int offset) throws RemoteException
 public  void registerDebugger(String lang,
    BSFDebugger debugger) throws RemoteException
    Register a debugger for a scripting engine.
 public  void removeBreakpoint(String docname,
    int brkptid) throws RemoteException
    Allows to remove a breakpoint.
 public  void setEntryExit(String docname,
    boolean on) throws RemoteException
    Allows setting entry/exit mode
 public boolean supportBreakpointAtLine(String lang) throws RemoteException
 public boolean supportBreakpointAtOffset(String lang) throws RemoteException
    Allows a debugger to ask if the engine for a given language
will support either line or offset breakpoints.
Note: this will most likely provoke the loading of the engine.
 public  void unregisterDebugger(String lang) throws RemoteException