org.ojai.util

Class BaseFieldProjector

java.lang.Object

org.ojai.util.BaseFieldProjector

All Implemented Interfaces:

JsonString

Direct Known Subclasses:

FieldProjector

@API.Public
public abstract class BaseFieldProjector
extends Object
implements JsonString

Field Summary

Fields

Modifier and Type	Field and Description
protected org.ojai.util.impl.ProjectionTree	currentSegment
protected boolean	includeAllChildren This flag indicates that the current Field should be projected because its FieldPath is a descendant of one of the projected fields.
protected boolean	includeField This flag indicates that the current Field should be projected because its FieldPath is a "suffix" of the FieldPath of one of the projected fields.
protected org.ojai.util.impl.ProjectionTree	lastSegment
protected int	level
protected org.ojai.util.impl.MutableFieldSegment	readerFieldSegment
protected org.ojai.util.impl.ProjectionTree	rootSegment

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
String	asJsonString()
String	asJsonString(JsonOptions options)
abstract BaseFieldProjector	cloneWithSharedProjectionTree() Creates a lightweight clone of this FieldProjector with shared ProjectionTree.
boolean	done() Returns true if ProjectionTree has visited all nodes
boolean	isDone() Returns true if ProjectionTree has visited all nodes
protected void	moveTo(DocumentReader.EventType event) This is the main algorithm that determine if the current DocumentReader or MutableFieldSegment node should be included or excluded based on the set of projected fields.
protected void	moveTo(org.ojai.util.impl.MutableFieldSegment keySegment, DocumentReader.EventType event) To be used when input Document is not from a DocumentReader but provided externally as a MutableFieldSegment.
BaseFieldProjector	reset() Resets the state of this projection tree to the root of the Document when not using with a DocumentReader.
protected BaseFieldProjector	reset(DocumentReader reader) Resets the state of this projection tree to the root of the Document.
protected boolean	shouldEmitEvent()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

rootSegment

protected final org.ojai.util.impl.ProjectionTree rootSegment

currentSegment

protected org.ojai.util.impl.ProjectionTree currentSegment

lastSegment

protected org.ojai.util.impl.ProjectionTree lastSegment

readerFieldSegment

protected org.ojai.util.impl.MutableFieldSegment readerFieldSegment

level

protected int level

includeField

protected boolean includeField

This flag indicates that the current Field should be projected because its FieldPath is a "suffix" of the FieldPath of one of the projected fields.

For example, is "a.b.c" is is one of the projected FieldPath then, this is set for "a", "a.b", and "a.b.c" but not for "a.b.c.d".

includeAllChildren

protected boolean includeAllChildren

This flag indicates that the current Field should be projected because its FieldPath is a descendant of one of the projected fields.

Constructor Detail

BaseFieldProjector

protected BaseFieldProjector(@API.NonNullable
                             String... includedPaths)

BaseFieldProjector

protected BaseFieldProjector(@API.NonNullable
                             FieldPath... includedPaths)

BaseFieldProjector

protected BaseFieldProjector(@API.NonNullable
                             Collection<FieldPath> includedPaths)

BaseFieldProjector

protected BaseFieldProjector(org.ojai.util.impl.ProjectionTree rootSegment)

Method Detail

cloneWithSharedProjectionTree

public abstract BaseFieldProjector cloneWithSharedProjectionTree()

Creates a lightweight clone of this FieldProjector with shared ProjectionTree.

shouldEmitEvent

protected boolean shouldEmitEvent()

moveTo

protected void moveTo(DocumentReader.EventType event)

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

moveTo

protected void moveTo(org.ojai.util.impl.MutableFieldSegment keySegment,
                      DocumentReader.EventType event)

To be used when input Document is not from a DocumentReader but provided externally as a MutableFieldSegment. A MutableFieldSegment can represent an IndexSegment or FieldSegment.NameSegment with appropriate attributes set. A single MutableFieldSegment should represent on independent FieldSegment which is part of a FieldPath that has been encountered while decoding or traversing a Document. When moveTo is called with a MutableFieldSegment keySegment input, the method will try to search if the keySegment is a child of the currentSegment. The outcome of the search is captured in the BaseFieldProjector state. The caller can subsequently call shouldEmitEvent in order to find out whether the child keySegment was found. If the child keySegment is indeed found, the currentSegment will be set to the child keySegment. Since moveTo can cause a change to the currentSegment being pointed to, in a hierarchical tree traversal, the effect of walking 'down' the ProjectionTree needs to be reversed when walking back 'up' the ProjectionTree. Therefore, moveTo should be called twice for each MutableFieldSegment - once to traverse 'down' the tree and once to travrse back 'up'.

isDone

public boolean isDone()

Returns true if ProjectionTree has visited all nodes

reset

protected BaseFieldProjector reset(DocumentReader reader)

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

Returns:

this for chaining.

reset

public BaseFieldProjector reset()

Resets the state of this projection tree to the root of the Document when not using with a DocumentReader.

Returns:

this for chaining;

done

public boolean done()

Returns true if ProjectionTree has visited all nodes

toString

public String toString()

Overrides:

toString in class Object

asJsonString

public String asJsonString()

Specified by:

asJsonString in interface JsonString

Returns:

this OJAI object serialized as JSON string using the default options

asJsonString

public String asJsonString(JsonOptions options)

Specified by:

asJsonString in interface JsonString

Returns:

this OJAI object serialized as JSON string using the specified options