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Added links to documentation

This commit is contained in:
Sam Harwell 2014-01-23 06:36:09 -06:00
parent aba1178c49
commit 58cc8f28d7
1 changed files with 29 additions and 24 deletions
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53
runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
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@ -199,33 +199,38 @@ import java.util.Set;
* <p>
* All instances of the same parser share the same decision DFAs through a
* static field. Each instance gets its own ATN simulator but they share the
* same decisionToDFA field. They also share a PredictionContextCache object
* that makes sure that all PredictionContext objects are shared among the DFA
* states. This makes a big size difference.</p>
* same {@link #decisionToDFA} field. They also share a
* {@link PredictionContextCache} object that makes sure that all
* {@link PredictionContext} objects are shared among the DFA states. This makes
* a big size difference.</p>
*
* <p>
* <strong>THREAD SAFETY</strong></p>
*
* <p>
* The parser ATN simulator locks on the decisionDFA field when it adds a new
* DFA object to that array. addDFAEdge locks on the DFA for the current
* decision when setting the edges[] field. addDFAState locks on the DFA for the
* current decision when looking up a DFA state to see if it already exists. We
* must make sure that all requests to add DFA states that are equivalent result
* in the same shared DFA object. This is because lots of threads will be trying
* to update the DFA at once. The addDFAState method also locks inside the DFA
* lock but this time on the shared context cache when it rebuilds the
* configurations' PredictionContext objects using cached subgraphs/nodes. No
* other locking occurs, even during DFA simulation. This is safe as long as we
* can guarantee that all threads referencing s.edge[t] get the same physical
* target DFA state, or none. Once into the DFA, the DFA simulation does not
* reference the dfa.state map. It follows the edges[] field to new targets. The
* DFA simulator will either find dfa.edges to be null, to be non-null and
* dfa.edges[t] null, or dfa.edges[t] to be non-null. The addDFAEdge method
* could be racing to set the field but in either case the DFA simulator works;
* if null, and requests ATN simulation. It could also race trying to get
* dfa.edges[t], but either way it will work because it's not doing a test and
* set operation.</p>
* The {@link ParserATNSimulator} locks on the {@link #decisionToDFA} field when
* it adds a new DFA object to that array. {@link #addDFAEdge}
* locks on the DFA for the current decision when setting the
* {@link DFAState#edges} field. {@link #addDFAState} locks on
* the DFA for the current decision when looking up a DFA state to see if it
* already exists. We must make sure that all requests to add DFA states that
* are equivalent result in the same shared DFA object. This is because lots of
* threads will be trying to update the DFA at once. The
* {@link #addDFAState} method also locks inside the DFA lock
* but this time on the shared context cache when it rebuilds the
* configurations' {@link PredictionContext} objects using cached
* subgraphs/nodes. No other locking occurs, even during DFA simulation. This is
* safe as long as we can guarantee that all threads referencing
* {@code s.edge[t]} get the same physical target {@link DFAState}, or
* {@code null}. Once into the DFA, the DFA simulation does not reference the
* {@link DFA#states} map. It follows the {@link DFAState#edges} field to new
* targets. The DFA simulator will either find {@link DFAState#edges} to be
* {@code null}, to be non-{@code null} and {@code dfa.edges[t]} null, or
* {@code dfa.edges[t]} to be non-null. The
* {@link #addDFAEdge} method could be racing to set the field
* but in either case the DFA simulator works; if {@code null}, and requests ATN
* simulation. It could also race trying to get {@code dfa.edges[t]}, but either
* way it will work because it's not doing a test and set operation.</p>
*
* <p>
* <strong>Starting with SLL then failing to combined SLL/LL</strong></p>
@ -237,14 +242,14 @@ import java.util.Set;
* mode:</p>
*
* <pre>
* parser.getInterpreter().setSLL(true);
* parser.{@link Parser#getInterpreter() getInterpreter()}.{@link #setSLL setSLL(true)};
* </pre>
*
* <p>
* and with the bail error strategy:</p>
*
* <pre>
* parser.setErrorHandler(new BailErrorStrategy());
* parser.{@link Parser#setErrorHandler setErrorHandler}(new {@link BailErrorStrategy}());
* </pre>
*
* <p>