org.ojai.util

Class FieldProjector

java.lang.Object

org.ojai.util.BaseFieldProjector

org.ojai.util.FieldProjector

All Implemented Interfaces:

JsonString

@API.Public
public final class FieldProjector
extends BaseFieldProjector

A helper class, which maintains a projection tree built form the list of user specified FieldPaths and in association with a DocumentReader, determines which fields form the document reader are emitted to the applications.

A single instance of ProjectionTree can not be, concurrently, used with multiple DocumentReaders. Use cloneWithSharedProjectionTree() in such cases.

Field Summary

Fields inherited from class org.ojai.util.BaseFieldProjector

currentSegment, includeAllChildren, includeField, lastSegment, level, readerFieldSegment, rootSegment

Constructor Summary

Constructors

Constructor and Description
FieldProjector(Collection<FieldPath> includedPaths)
FieldProjector(FieldPath... includedPaths)
FieldProjector(org.ojai.util.impl.ProjectionTree rootSegment)
FieldProjector(String... includedPaths)

Method Summary

Modifier and Type	Method and Description
FieldProjector	cloneWithSharedProjectionTree() Creates a lightweight clone of this FieldProjector with shared ProjectionTree.
void	moveTo(DocumentReader.EventType event) This is the main algorithm that determine if the current DocumentReader node should be included or excluded based on the set of projected fields.
FieldProjector	reset(DocumentReader reader) Resets the state of this projection tree to the root of the Document.

Methods inherited from class org.ojai.util.BaseFieldProjector

asJsonString, asJsonString, done, isDone, moveTo, reset, shouldEmitEvent, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldProjector

public FieldProjector(@API.NonNullable
                      String... includedPaths)

FieldProjector

public FieldProjector(@API.NonNullable
                      FieldPath... includedPaths)

FieldProjector

public FieldProjector(@API.NonNullable
                      Collection<FieldPath> includedPaths)

FieldProjector

public FieldProjector(org.ojai.util.impl.ProjectionTree rootSegment)

Method Detail

cloneWithSharedProjectionTree

public FieldProjector cloneWithSharedProjectionTree()

Creates a lightweight clone of this FieldProjector with shared ProjectionTree.

Specified by:

cloneWithSharedProjectionTree in class BaseFieldProjector

moveTo

public void moveTo(DocumentReader.EventType event)

This is the main algorithm that determine if the current DocumentReader node should be included or excluded based on the set of projected fields.

Overrides:

moveTo in class BaseFieldProjector

reset

public FieldProjector reset(DocumentReader reader)

Resets the state of this projection tree to the root of the Document.

Overrides:

reset in class BaseFieldProjector

Returns:

this for chaining.