com.redhat.lightblue.crud.mongo

Class Merge

java.lang.Object

com.redhat.lightblue.crud.mongo.Merge

public final class Merge
extends Object

During a save operation, the document provided by the client replaces the copy in the database. If the client has a more limited view of data than is already present (i.e. client using an earlier version of metadata), then there may be some invisible fields, fields that are in the document, but not in the metadata used by the client. To prevent overwriting those fields, we perform a merge operation: all invisible fields are preserved in the updated document.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Merge.IField
static class	Merge.PathAndField

Constructor Summary

Constructors

Constructor and Description
Merge(com.redhat.lightblue.metadata.EntityMetadata md) Initialize with the metadata of the new object

Method Summary

Methods

Modifier and Type	Method and Description
void	findInvisibleFields(com.mongodb.DBObject dbObject) Construct the initial state of Merge by going through all the fields in the DBObject, and checking if they exist in metadata.
List<Merge.PathAndField>	getArrayIdentifiers(com.redhat.lightblue.util.Path arrayElementField) Returns all array element ids.
List<Merge.IField>	getIdentifyingContent(List<Merge.PathAndField> identifiers, com.mongodb.DBObject parent)
List<Merge.IField>	getInvisibleFields()
void	merge(com.mongodb.DBObject oldCopy, com.mongodb.DBObject newCopy) Attempts to copy the invisible fields in oldCopy into newCopy.
void	reset() Reset the internal state of the Merge

Methods inherited from class java.lang.Object

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

Constructor Detail

Merge

public Merge(com.redhat.lightblue.metadata.EntityMetadata md)

Initialize with the metadata of the new object

Method Detail

reset

public void reset()

Reset the internal state of the Merge

merge

public void merge(com.mongodb.DBObject oldCopy,
         com.mongodb.DBObject newCopy)

Attempts to copy the invisible fields in oldCopy into newCopy. If the attemp is unsucessful, Error is thrown.

getInvisibleFields

public List<Merge.IField> getInvisibleFields()

getIdentifyingContent

public List<Merge.IField> getIdentifyingContent(List<Merge.PathAndField> identifiers,
                                       com.mongodb.DBObject parent)

getArrayIdentifiers

public List<Merge.PathAndField> getArrayIdentifiers(com.redhat.lightblue.util.Path arrayElementField)

Returns all array element ids. If there are none, returns all UID fields. Search starts from the array element, and does not descend into any nested arrays.

findInvisibleFields

public void findInvisibleFields(com.mongodb.DBObject dbObject)

Construct the initial state of Merge by going through all the fields in the DBObject, and checking if they exist in metadata. Those fields that don't exist in metadata will be stored in the invisibleFields list.