Top Description Fields Constructors Methods
org.antlr.runtime.debug

public Class DebugEventRepeater

extends Object
implements DebugEventListener
Class Inheritance
All Implemented Interfaces
org.antlr.runtime.debug.DebugEventListener
Imports
org.antlr.runtime.Token, .RecognitionException

A simple event repeater (proxy) that delegates all functionality to the listener sent into the ctor. Useful if you want to listen in on a few debug events w/o interrupting the debugger. Just subclass the repeater and override the methods you want to listen in on. Remember to call the method in this class so the event will continue on to the original recipient.
See Also
DebugEventHub

Field Summary

Modifier and TypeField and Description
protected DebugEventListener

Constructor Summary

AccessConstructor and Description
public

Method Summary

Modifier and TypeMethod and Description
public void
addChild(Object root, Object child)

Implements org.antlr.runtime.debug.DebugEventListener.addChild.

Make childID a child of rootID.
public void
becomeRoot(Object newRoot, Object oldRoot)

Implements org.antlr.runtime.debug.DebugEventListener.becomeRoot.

Make a node the new root of an existing root.
public void
public void
beginResync()

Implements org.antlr.runtime.debug.DebugEventListener.beginResync.

Indicates the recognizer is about to consume tokens to resynchronize the parser.
public void
commence()

Implements org.antlr.runtime.debug.DebugEventListener.commence.

Announce that parsing has begun.
public void
consumeHiddenToken(Token token)

Implements org.antlr.runtime.debug.DebugEventListener.consumeHiddenToken.

An off-channel input token was consumed.
public void
consumeNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.consumeNode.

Input for a tree parser is an AST, but we know nothing for sure about a node except its type and text (obtained from the adaptor).
public void
consumeToken(Token token)

Implements org.antlr.runtime.debug.DebugEventListener.consumeToken.

An input token was consumed; matched by any kind of element.
public void
createNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.createNode.

Announce a new node built from token elements such as type etc...
public void
createNode(Object node, Token token)

Implements org.antlr.runtime.debug.DebugEventListener.createNode.

Announce a new node built from an existing token.
public void
public void
endResync()

Implements org.antlr.runtime.debug.DebugEventListener.endResync.

Indicates that the recognizer has finished consuming tokens in order to resychronize.
public void
enterAlt(int alt)

Implements org.antlr.runtime.debug.DebugEventListener.enterAlt.

Because rules can have lots of alternatives, it is very useful to know which alt you are entering.
public void
enterDecision(int decisionNumber, boolean couldBacktrack)

Implements org.antlr.runtime.debug.DebugEventListener.enterDecision.

Every decision, fixed k or arbitrary, has an enter/exit event so that a GUI can easily track what LT/consume events are associated with prediction.
public void
enterRule(String grammarFileName, String ruleName)

Implements org.antlr.runtime.debug.DebugEventListener.enterRule.

The parser has just entered a rule.
public void
enterSubRule(int decisionNumber)

Implements org.antlr.runtime.debug.DebugEventListener.enterSubRule.

Track entry into any (...) subrule other EBNF construct
public void
errorNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.errorNode.

Upon syntax error, recognizers bracket the error with an error node if they are building ASTs.
public void
public void
exitRule(String grammarFileName, String ruleName)

Implements org.antlr.runtime.debug.DebugEventListener.exitRule.

This is the last thing executed before leaving a rule.
public void
public void
location(int line, int pos)

Implements org.antlr.runtime.debug.DebugEventListener.location.

To watch a parser move through the grammar, the parser needs to inform the debugger what line/charPos it is passing in the grammar.
public void
LT(int i, Token t)

Implements org.antlr.runtime.debug.DebugEventListener.LT.

Somebody (anybody) looked ahead.
public void
LT(int i, Object t)

Implements org.antlr.runtime.debug.DebugEventListener.LT.

The tree parser lookedahead.
public void
mark(int i)

Implements org.antlr.runtime.debug.DebugEventListener.mark.

The parser is going to look arbitrarily ahead; mark this location, the token stream's marker is sent in case you need it.
public void
nilNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.nilNode.

A nil was created (even nil nodes have a unique ID...
public void
recognitionException(RecognitionException e)

Implements org.antlr.runtime.debug.DebugEventListener.recognitionException.

A recognition exception occurred such as NoViableAltException.
public void
rewind(int i)

Implements org.antlr.runtime.debug.DebugEventListener.rewind.

After an arbitrairly long lookahead as with a cyclic DFA (or with any backtrack), this informs the debugger that stream should be rewound to the position associated with marker.
public void
rewind()

Implements org.antlr.runtime.debug.DebugEventListener.rewind.

Rewind to the input position of the last marker.
public void
semanticPredicate(boolean result, String predicate)

Implements org.antlr.runtime.debug.DebugEventListener.semanticPredicate.

A semantic predicate was evaluate with this result and action text
public void
setTokenBoundaries(Object t, int tokenStartIndex, int tokenStopIndex)

Implements org.antlr.runtime.debug.DebugEventListener.setTokenBoundaries.

Set the token start/stop token index for a subtree root or node.
public void
terminate()

Implements org.antlr.runtime.debug.DebugEventListener.terminate.

Parsing is over; successfully or not.
Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

listenerback to summary
protected DebugEventListener listener

Constructor Detail

DebugEventRepeaterback to summary
public DebugEventRepeater(DebugEventListener listener)

Method Detail

addChildback to summary
public void addChild(Object root, Object child)

Implements org.antlr.runtime.debug.DebugEventListener.addChild.

Doc from org.antlr.runtime.debug.DebugEventListener.addChild.

Make childID a child of rootID. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only IDs are set.

Annotations
@Override
becomeRootback to summary
public void becomeRoot(Object newRoot, Object oldRoot)

Implements org.antlr.runtime.debug.DebugEventListener.becomeRoot.

Doc from org.antlr.runtime.debug.DebugEventListener.becomeRoot.

Make a node the new root of an existing root. See

Note

the newRootID parameter is possibly different than the TreeAdaptor.becomeRoot() newRoot parameter. In our case, it will always be the result of calling TreeAdaptor.becomeRoot() and not root_n or whatever. The listener should assume that this event occurs only when the current subrule (or rule) subtree is being reset to newRootID. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only IDs are set.

Annotations
@Override
beginBacktrackback to summary
public void beginBacktrack(int level)

Implements org.antlr.runtime.debug.DebugEventListener.beginBacktrack.

Annotations
@Override
beginResyncback to summary
public void beginResync()

Implements org.antlr.runtime.debug.DebugEventListener.beginResync.

Doc from org.antlr.runtime.debug.DebugEventListener.beginResync.

Indicates the recognizer is about to consume tokens to resynchronize the parser. Any consume events from here until the recovered event are not part of the parse--they are dead tokens.

Annotations
@Override
commenceback to summary
public void commence()

Implements org.antlr.runtime.debug.DebugEventListener.commence.

Doc from org.antlr.runtime.debug.DebugEventListener.commence.

Announce that parsing has begun. Not technically useful except for sending events over a socket. A GUI for example will launch a thread to connect and communicate with a remote parser. The thread will want to notify the GUI when a connection is made. ANTLR parsers trigger this upon entry to the first rule (the ruleLevel is used to figure this out).

Annotations
@Override
consumeHiddenTokenback to summary
public void consumeHiddenToken(Token token)

Implements org.antlr.runtime.debug.DebugEventListener.consumeHiddenToken.

Doc from org.antlr.runtime.debug.DebugEventListener.consumeHiddenToken.

An off-channel input token was consumed. Trigger after the token was matched by things like match(), matchAny(). (unless of course the hidden token is first stuff in the input stream).

Annotations
@Override
consumeNodeback to summary
public void consumeNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.consumeNode.

Doc from org.antlr.runtime.debug.DebugEventListener.consumeNode.

Input for a tree parser is an AST, but we know nothing for sure about a node except its type and text (obtained from the adaptor). This is the analog of the consumeToken method. Again, the ID is the hashCode usually of the node so it only works if hashCode is not implemented. If the type is UP or DOWN, then the ID is not really meaningful as it's fixed--there is just one UP node and one DOWN navigation node.

Annotations
@Override
consumeTokenback to summary
public void consumeToken(Token token)

Implements org.antlr.runtime.debug.DebugEventListener.consumeToken.

Doc from org.antlr.runtime.debug.DebugEventListener.consumeToken.

An input token was consumed; matched by any kind of element. Trigger after the token was matched by things like match(), matchAny().

Annotations
@Override
createNodeback to summary
public void createNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.createNode.

Doc from org.antlr.runtime.debug.DebugEventListener.createNode.

Announce a new node built from token elements such as type etc... If you are receiving this event over a socket via RemoteDebugEventSocketListener then only t.ID, type, text are set.

Annotations
@Override
createNodeback to summary
public void createNode(Object node, Token token)

Implements org.antlr.runtime.debug.DebugEventListener.createNode.

Doc from org.antlr.runtime.debug.DebugEventListener.createNode.

Announce a new node built from an existing token. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only node.ID and token.tokenIndex are set.

Annotations
@Override
endBacktrackback to summary
public void endBacktrack(int level, boolean successful)

Implements org.antlr.runtime.debug.DebugEventListener.endBacktrack.

Annotations
@Override
endResyncback to summary
public void endResync()

Implements org.antlr.runtime.debug.DebugEventListener.endResync.

Doc from org.antlr.runtime.debug.DebugEventListener.endResync.

Indicates that the recognizer has finished consuming tokens in order to resychronize. There may be multiple beginResync/endResync pairs before the recognizer comes out of errorRecovery mode (in which multiple errors are suppressed). This will be useful in a gui where you want to probably grey out tokens that are consumed but not matched to anything in grammar. Anything between a beginResync/endResync pair was tossed out by the parser.

Annotations
@Override
enterAltback to summary
public void enterAlt(int alt)

Implements org.antlr.runtime.debug.DebugEventListener.enterAlt.

Doc from org.antlr.runtime.debug.DebugEventListener.enterAlt.

Because rules can have lots of alternatives, it is very useful to know which alt you are entering. This is 1..n for n alts.

Annotations
@Override
enterDecisionback to summary
public void enterDecision(int decisionNumber, boolean couldBacktrack)

Implements org.antlr.runtime.debug.DebugEventListener.enterDecision.

Doc from org.antlr.runtime.debug.DebugEventListener.enterDecision.

Every decision, fixed k or arbitrary, has an enter/exit event so that a GUI can easily track what LT/consume events are associated with prediction. You will see a single enter/exit subrule but multiple enter/exit decision events, one for each loop iteration.

Annotations
@Override
enterRuleback to summary
public void enterRule(String grammarFileName, String ruleName)

Implements org.antlr.runtime.debug.DebugEventListener.enterRule.

Doc from org.antlr.runtime.debug.DebugEventListener.enterRule.

The parser has just entered a rule. No decision has been made about which alt is predicted. This is fired AFTER init actions have been executed. Attributes are defined and available etc... The grammarFileName allows composite grammars to jump around among multiple grammar files.

Annotations
@Override
enterSubRuleback to summary
public void enterSubRule(int decisionNumber)

Implements org.antlr.runtime.debug.DebugEventListener.enterSubRule.

Doc from org.antlr.runtime.debug.DebugEventListener.enterSubRule.

Track entry into any (...) subrule other EBNF construct

Annotations
@Override
errorNodeback to summary
public void errorNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.errorNode.

Doc from org.antlr.runtime.debug.DebugEventListener.errorNode.

Upon syntax error, recognizers bracket the error with an error node if they are building ASTs.

Annotations
@Override
exitDecisionback to summary
public void exitDecision(int decisionNumber)

Implements org.antlr.runtime.debug.DebugEventListener.exitDecision.

Annotations
@Override
exitRuleback to summary
public void exitRule(String grammarFileName, String ruleName)

Implements org.antlr.runtime.debug.DebugEventListener.exitRule.

Doc from org.antlr.runtime.debug.DebugEventListener.exitRule.

This is the last thing executed before leaving a rule. It is executed even if an exception is thrown. This is triggered after error reporting and recovery have occurred (unless the exception is not caught in this rule). This implies an "exitAlt" event. The grammarFileName allows composite grammars to jump around among multiple grammar files.

Annotations
@Override
exitSubRuleback to summary
public void exitSubRule(int decisionNumber)

Implements org.antlr.runtime.debug.DebugEventListener.exitSubRule.

Annotations
@Override
locationback to summary
public void location(int line, int pos)

Implements org.antlr.runtime.debug.DebugEventListener.location.

Doc from org.antlr.runtime.debug.DebugEventListener.location.

To watch a parser move through the grammar, the parser needs to inform the debugger what line/charPos it is passing in the grammar. For now, this does not know how to switch from one grammar to the other and back for island grammars etc... This should also allow breakpoints because the debugger can stop the parser whenever it hits this line/pos.

Annotations
@Override
LTback to summary
public void LT(int i, Token t)

Implements org.antlr.runtime.debug.DebugEventListener.LT.

Doc from org.antlr.runtime.debug.DebugEventListener.LT.

Somebody (anybody) looked ahead. Note that this actually gets triggered by both LA and LT calls. The debugger will want to know which Token object was examined. Like consumeToken, this indicates what token was seen at that depth. A remote debugger cannot look ahead into a file it doesn't have so LT events must pass the token even if the info is redundant.

Annotations
@Override
LTback to summary
public void LT(int i, Object t)

Implements org.antlr.runtime.debug.DebugEventListener.LT.

Doc from org.antlr.runtime.debug.DebugEventListener.LT.

The tree parser lookedahead. If the type is UP or DOWN, then the ID is not really meaningful as it's fixed--there is just one UP node and one DOWN navigation node.

Annotations
@Override
markback to summary
public void mark(int i)

Implements org.antlr.runtime.debug.DebugEventListener.mark.

Doc from org.antlr.runtime.debug.DebugEventListener.mark.

The parser is going to look arbitrarily ahead; mark this location, the token stream's marker is sent in case you need it.

Annotations
@Override
nilNodeback to summary
public void nilNode(Object t)

Implements org.antlr.runtime.debug.DebugEventListener.nilNode.

Doc from org.antlr.runtime.debug.DebugEventListener.nilNode.

A nil was created (even nil nodes have a unique ID... they are not "null" per se). As of 4/28/2006, this seems to be uniquely triggered when starting a new subtree such as when entering a subrule in automatic mode and when building a tree in rewrite mode. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only t.ID is set.

Annotations
@Override
recognitionExceptionback to summary
public void recognitionException(RecognitionException e)

Implements org.antlr.runtime.debug.DebugEventListener.recognitionException.

Doc from org.antlr.runtime.debug.DebugEventListener.recognitionException.

A recognition exception occurred such as NoViableAltException. I made this a generic event so that I can alter the exception hierachy later without having to alter all the debug objects. Upon error, the stack of enter rule/subrule must be properly unwound. If no viable alt occurs it is within an enter/exit decision, which also must be rewound. Even the rewind for each mark must be unwount. In the Java target this is pretty easy using try/finally, if a bit ugly in the generated code. The rewind is generated in DFA.predict() actually so no code needs to be generated for that. For languages w/o this "finally" feature (C++?), the target implementor will have to build an event stack or something. Across a socket for remote debugging, only the RecognitionException data fields are transmitted. The token object or whatever that caused the problem was the last object referenced by LT. The immediately preceding LT event should hold the unexpected Token or char. Here is a sample event trace for grammar: b : C ({;}A|B) // {;} is there to prevent A|B becoming a set | D ; The sequence for this rule (with no viable alt in the subrule) for input 'c c' (there are 3 tokens) is: commence LT(1) enterRule b location 7 1 enter decision 3 LT(1) exit decision 3 enterAlt1 location 7 5 LT(1) consumeToken [c/<4>,1:0] location 7 7 enterSubRule 2 enter decision 2 LT(1) LT(1) recognitionException NoViableAltException 2 1 2 exit decision 2 exitSubRule 2 beginResync LT(1) consumeToken [c/<4>,1:1] LT(1) endResync LT(-1) exitRule b terminate

Annotations
@Override
rewindback to summary
public void rewind(int i)

Implements org.antlr.runtime.debug.DebugEventListener.rewind.

Doc from org.antlr.runtime.debug.DebugEventListener.rewind.

After an arbitrairly long lookahead as with a cyclic DFA (or with any backtrack), this informs the debugger that stream should be rewound to the position associated with marker.

Annotations
@Override
rewindback to summary
public void rewind()

Implements org.antlr.runtime.debug.DebugEventListener.rewind.

Doc from org.antlr.runtime.debug.DebugEventListener.rewind.

Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still.

Annotations
@Override
semanticPredicateback to summary
public void semanticPredicate(boolean result, String predicate)

Implements org.antlr.runtime.debug.DebugEventListener.semanticPredicate.

Doc from org.antlr.runtime.debug.DebugEventListener.semanticPredicate.

A semantic predicate was evaluate with this result and action text

Annotations
@Override
setTokenBoundariesback to summary
public void setTokenBoundaries(Object t, int tokenStartIndex, int tokenStopIndex)

Implements org.antlr.runtime.debug.DebugEventListener.setTokenBoundaries.

Doc from org.antlr.runtime.debug.DebugEventListener.setTokenBoundaries.

Set the token start/stop token index for a subtree root or node. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only t.ID is set.

Annotations
@Override
terminateback to summary
public void terminate()

Implements org.antlr.runtime.debug.DebugEventListener.terminate.

Doc from org.antlr.runtime.debug.DebugEventListener.terminate.

Parsing is over; successfully or not. Mostly useful for telling remote debugging listeners that it's time to quit. When the rule invocation level goes to zero at the end of a rule, we are done parsing.

Annotations
@Override