Package org.apache.tinkerpop.gremlin.server.op

Class AbstractEvalOpProcessor

java.lang.Object

org.apache.tinkerpop.gremlin.server.op.AbstractOpProcessor

org.apache.tinkerpop.gremlin.server.op.AbstractEvalOpProcessor

All Implemented Interfaces:

AutoCloseable, OpProcessor

Direct Known Subclasses:

SessionOpProcessor, StandardOpProcessor

public abstract class AbstractEvalOpProcessor
extends AbstractOpProcessor

A base OpProcessor implementation that helps with operations that deal with script evaluation functions.

Author:

Stephen Mallette (http://stephen.genoprime.com)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	AbstractEvalOpProcessor.BindingSupplier

Field Summary

Fields

Modifier and Type	Field	Description
static String	CONFIG_MAX_PARAMETERS	The maximum number of parameters that can be passed on a script evaluation request.
static int	DEFAULT_MAX_PARAMETERS	Default number of parameters allowed on a script evaluation request.
static com.codahale.metrics.Timer	evalOpTimer
protected static Set<String>	INVALID_BINDINGS_KEYS	This may or may not be the full set of invalid binding keys.
protected int	maxParameters

Fields inherited from class org.apache.tinkerpop.gremlin.server.op.AbstractOpProcessor

manageTransactions

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractEvalOpProcessor(boolean manageTransactions)

Method Summary

Modifier and Type	Method	Description
protected void	evalOpInternal(Context ctx, Supplier<GremlinExecutor> gremlinExecutorSupplier, AbstractEvalOpProcessor.BindingSupplier bindingsSupplier)	A generalized implementation of the "eval" operation.
abstract ThrowingConsumer<Context>	getEvalOp()	Provides an operation for evaluating a Gremlin script.
ThrowingConsumer<Context>	select(Context ctx)	Given the context (which contains the RequestMessage), return back a Consumer function that will be executed with the context.
abstract Optional<ThrowingConsumer<Context>>	selectOther(Context ctx)	A sub-class may have additional "ops" that it will service.
protected Optional<ThrowingConsumer<Context>>	validateEvalMessage(RequestMessage message)

Methods inherited from class org.apache.tinkerpop.gremlin.server.op.AbstractOpProcessor

attemptCommit, attemptRollback, determineIfSpecialException, generateResultMetaData, generateStatusAttributes, handleIterator, isForceFlushed, iterateComplete, makeFrame

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.AutoCloseable

close

Methods inherited from interface org.apache.tinkerpop.gremlin.server.OpProcessor

getName, init

Field Detail

evalOpTimer

public static final com.codahale.metrics.Timer evalOpTimer

CONFIG_MAX_PARAMETERS

public static final String CONFIG_MAX_PARAMETERS

The maximum number of parameters that can be passed on a script evaluation request.

See Also:

Constant Field Values

DEFAULT_MAX_PARAMETERS

public static final int DEFAULT_MAX_PARAMETERS

Default number of parameters allowed on a script evaluation request.

See Also:

Constant Field Values

maxParameters

protected int maxParameters

INVALID_BINDINGS_KEYS

protected static final Set<String> INVALID_BINDINGS_KEYS

This may or may not be the full set of invalid binding keys. It is dependent on the static imports made to Gremlin Server. This should get rid of the worst offenders though and provide a good message back to the calling client.

Use of toUpperCase() on the accessor values of T solves an issue where the ScriptEngine ignores private scope on T and imports static fields.

Constructor Detail

AbstractEvalOpProcessor

protected AbstractEvalOpProcessor(boolean manageTransactions)

Method Detail

getEvalOp

public abstract ThrowingConsumer<Context> getEvalOp()

Provides an operation for evaluating a Gremlin script.

Returns:

selectOther

public abstract Optional<ThrowingConsumer<Context>> selectOther(Context ctx)
                                                         throws OpProcessorException

A sub-class may have additional "ops" that it will service. Calls to OpProcessor.select(Context) that are not handled will be passed to this method to see if the sub-class can service the requested op code.

Returns:

Throws:

OpProcessorException

select

public ThrowingConsumer<Context> select(Context ctx)
                                 throws OpProcessorException

Description copied from interface: OpProcessor

Given the context (which contains the RequestMessage), return back a Consumer function that will be executed with the context. A typical implementation will simply check the "op" field on the RequestMessage and return the Consumer function for that particular operation.

Returns:

Throws:

OpProcessorException

validateEvalMessage

protected Optional<ThrowingConsumer<Context>> validateEvalMessage(RequestMessage message)
                                                           throws OpProcessorException

Throws:

OpProcessorException

evalOpInternal

protected void evalOpInternal(Context ctx,
                              Supplier<GremlinExecutor> gremlinExecutorSupplier,
                              AbstractEvalOpProcessor.BindingSupplier bindingsSupplier)

A generalized implementation of the "eval" operation. It handles script evaluation and iteration of results so as to write ResponseMessage objects down the Netty pipeline. It also handles script timeouts, iteration timeouts, metrics and building bindings. Note that result iteration is delegated to the AbstractOpProcessor.handleIterator(Context, Iterator) method, so those extending this class could override that method for better control over result iteration.

Parameters:

ctx - The current Gremlin Server Context. This handler ensures that only a single final response is sent to the client.

gremlinExecutorSupplier - A function that returns the GremlinExecutor to use in executing the script evaluation.

bindingsSupplier - A function that returns the Bindings to provide to the GremlinExecutor.eval(java.lang.String) method.