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 Summary

Fields

Modifier and Type	Field and Description
protected StreamDefinitionService	streamDefinitionService

Constructor Summary

Constructors

Constructor and Description
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.

Method Summary

Modifier and Type	Method and Description
boolean	shouldTrigger(String dslStart, Exception exception) Whether this completion should be triggered.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.springframework.cloud.dataflow.completion.RecoveryStrategy

addProposals

Field Detail

streamDefinitionService

protected StreamDefinitionService streamDefinitionService

Constructor Detail

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 Detail

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