org.hibernate.ogm.datastore.neo4j.query.parsing.impl

Class Neo4jAliasResolver

java.lang.Object

org.hibernate.ogm.datastore.neo4j.query.parsing.impl.Neo4jAliasResolver

public class Neo4jAliasResolver
extends Object

Keep track of the aliases needed to create the Cypher query.

Author:

Davide D'Alto, Guillaume Smet

Constructor Summary

Constructors

Constructor and Description
Neo4jAliasResolver()

Method Summary

Modifier and Type	Method and Description
String	createAliasForAssociation(String entityAlias, List<String> propertyPathWithoutAlias, String targetNodeType, boolean optionalMatch) Given the path to an association, it will create an alias to use in the query for the association.
String	createAliasForEmbedded(String entityAlias, List<String> propertyPathWithoutAlias, boolean optionalMatch) Given the path to an embedded property, it will create an alias to use in the query for the embedded containing the property.
String	findAlias(String entityAlias, List<String> propertyPathWithoutAlias) Given the alias of the entity and the path to the relationship it will return the alias of the component.
String	findAliasForType(String entityType)
RelationshipAliasTree	getRelationshipAliasTree(String entityAlias) Given the alias of the entity it will return a tree structure containing all the aliases for the embedded properties and associations of the entity.
boolean	isOptionalMatch(String alias) Tells if the alias has to be used in the OPTIONAL MATCH part of the query.
void	registerEntityAlias(String entityName, String alias)

Methods inherited from class java.lang.Object

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

Constructor Detail

Neo4jAliasResolver

public Neo4jAliasResolver()

Method Detail

registerEntityAlias

public void registerEntityAlias(String entityName,
                                String alias)

findAliasForType

public String findAliasForType(String entityType)

createAliasForEmbedded

public String createAliasForEmbedded(String entityAlias,
                                     List<String> propertyPathWithoutAlias,
                                     boolean optionalMatch)

Given the path to an embedded property, it will create an alias to use in the query for the embedded containing the property.

The alias will be saved and can be returned using the method findAlias(String, List).

For example, using n as entity alias and [embedded, anotherEmbedded] as path to the embedded will return "_n2" as alias for "n.embedded.anotherEmbedded".

Note that you need to create an alias for every embedded/association in the path before this one.

Parameters:

entityAlias - the alias of the entity that contains the embedded

propertyPathWithoutAlias - the path to the property without the alias

optionalMatch - if true, the alias does not represent a required match in the query (It will appear in the OPTIONAL MATCH clause)

Returns:

the alias of the embedded containing the property

createAliasForAssociation

public String createAliasForAssociation(String entityAlias,
                                        List<String> propertyPathWithoutAlias,
                                        String targetNodeType,
                                        boolean optionalMatch)

Given the path to an association, it will create an alias to use in the query for the association.

The alias will be saved and can be returned using the method findAlias(String, List).

For example, using n as entity alias and [association, anotherAssociation] as path to the association will return "_n2" as alias for "n.association.anotherAssociation".

Note that you need to create an alias for every embedded/association in the path before this one.

Parameters:

entityAlias - the alias of the entity that contains the embedded

propertyPathWithoutAlias - the path to the property without the alias

targetNodeType - the name of the target node type

optionalMatch - if true, the alias does not represent a required match in the query (It will appear in the OPTIONAL MATCH clause)

Returns:

the alias of the embedded containing the property

findAlias

public String findAlias(String entityAlias,
                        List<String> propertyPathWithoutAlias)

Given the alias of the entity and the path to the relationship it will return the alias of the component.

Parameters:

entityAlias - the alias of the entity

propertyPathWithoutAlias - the path to the property without the alias

Returns:

the alias the relationship or null

getRelationshipAliasTree

public RelationshipAliasTree getRelationshipAliasTree(String entityAlias)

Given the alias of the entity it will return a tree structure containing all the aliases for the embedded properties and associations of the entity.

The tree has the entity alias as root and the embedded/association alias as children. For example, a path to two properties like:

1. n.first.anotherEmbedded
2. n.second.anotherEmbedded

Might be represented with the following structure:

 n (alias = n)|- first (alias = _n1)  -- anotherEmbedded (alias = _n2)
              |
              -- second (alias = _n3) -- anotherEmbedded (alias = _n4)
 

Parameters:

entityAlias - the alias of the entity that contains the embedded

Returns:

the corresponding RelationshipAliasTree or null

isOptionalMatch

public boolean isOptionalMatch(String alias)

Tells if the alias has to be used in the OPTIONAL MATCH part of the query.

Parameters:

alias - the alis to check

Returns:

true if the alias should be used in OPTIONAL MATCH part of the query, false otherwise