Package org.springframework.cloud.dataflow.completion

Class StacktraceFingerprintingRecoveryStrategy<E extends Exception>

java.lang.Object
org.springframework.cloud.dataflow.completion.StacktraceFingerprintingRecoveryStrategy<E>
All Implemented Interfaces:
RecoveryStrategy<E>
Direct Known Subclasses:
AppsAfterDoublePipeRecoveryStrategy, AppsAfterPipeRecoveryStrategy, ConfigurationPropertyValueHintRecoveryStrategy, UnfinishedConfigurationPropertyNameRecoveryStrategy
public abstract class StacktraceFingerprintingRecoveryStrategy<E extends Exception> extends Object implements RecoveryStrategy<E>
A recovery strategy that will trigger if the parser failure is similar to that of some sample unfinished stream definition. The match is decided by analyzing the top frames of the stack trace emitted by the parser when it encounters the ill formed input. Multiple fingerprints are supported, as the control flow in the parser code may be different depending on the form of the expression. For example, for the rule stream = module (| module)* , the pseudo code for the parser may look like 
 
 stream() {
   module();  (1)
   while(moreInput()) {
     swallowPipe();
     module();  (2)
   }
 }
In that setup, whether we're dealing with the first module, or a subsequent module, stack frames would be different (see (1) and (2)).
Author:
Eric Bottard

  • Field Details

  • Constructor Details

    • StacktraceFingerprintingRecoveryStrategy

      public StacktraceFingerprintingRecoveryStrategy(Class<E> exceptionClass, StreamDefinitionService streamDefinitionService, String... samples)
      Construct a new StacktraceFingerprintingRecoveryStrategy given the parser, and the expected exception class to be thrown for sample fragments of a stream definition that is to be parsed.
      Parameters:
      exceptionClass - the expected exception that results from parsing the sample fragment stream definitions. Stack frames from the thrown exception are used to store the fingerprint of this exception thrown by the parser.
      streamDefinitionService - the service to handle stream definition
      samples - the sample fragments of stream definitions.

  • Method Details

    • shouldTrigger

      public boolean shouldTrigger(String dslStart, Exception exception)
      Description copied from interface: RecoveryStrategy
      Whether this completion should be triggered.
      Specified by:
      shouldTrigger in interface RecoveryStrategy<E extends Exception>
      Parameters:
      dslStart - the partial DSL text
      exception - the exception thrown when parsing the DSL text
      Returns:
      if proposals to complete the DSL should be provided