com.tinkerpop.gremlin.structure.util

Class ElementHelper

java.lang.Object

com.tinkerpop.gremlin.structure.util.ElementHelper

public class ElementHelper
extends java.lang.Object

Utility class supporting common functions for Element.

Author:

Marko A. Rodriguez (http://markorodriguez.com), Stephen Mallette (http://stephen.genoprime.com)

Constructor Summary

Constructors

Constructor and Description
ElementHelper()

Method Summary

Modifier and Type	Method and Description
static boolean	areEqual(Element a, java.lang.Object b) A standard method for determining if two Element objects are equal.
static boolean	areEqual(Property a, java.lang.Object b) A standard method for determining if two Property objects are equal.
static boolean	areEqual(VertexProperty a, java.lang.Object b) A standard method for determining if two VertexProperty objects are equal.
static java.util.Map<java.lang.String,java.lang.Object>	asMap(java.lang.Object... keyValues) Converts a set of key values to a Map.
static java.util.List<org.javatuples.Pair<java.lang.String,java.lang.Object>>	asPairs(java.lang.Object... keyValues) Convert a set of key values to a list of Pair objects.
static void	attachProperties(Element element, java.lang.Object... propertyKeyValues) Assign key/value pairs as properties to an Element.
static void	attachSingleProperties(Vertex vertex, java.lang.Object... propertyKeyValues) Assign key/value pairs as properties to an Vertex.
static java.util.Optional<java.lang.Object>	getIdValue(java.lang.Object... keyValues) Extracts the value of the T.id key from the list of arguments.
static java.util.Set<java.lang.String>	getKeys(java.lang.Object... keyValues) Gets the list of keys from the key values.
static java.util.Optional<java.lang.String>	getLabelValue(java.lang.Object... keyValues) Extracts the value of the T.label key from the list of arguments.
static Vertex	getOrAddVertex(Graph graph, java.lang.Object id, java.lang.String label) Check if the vertex, by ID, exists.
static java.lang.Object[]	getProperties(Element element, boolean includeId, boolean includeLabel, java.util.Set<java.lang.String> propertiesToCopy) Retrieve the properties associated with a particular element.
static int	hashCode(Element element) If two Element instances are equal, then they must have the same hash codes.
static int	hashCode(Property property) If two Property instances are equal, then they must have the same hash codes.
static boolean	haveEqualIds(Element a, Element b) Simply tests if the value returned from Element.id() are equal().
static boolean	idExists(java.lang.Object id, java.lang.Object... providedIds)
static boolean	keyExists(java.lang.String key, java.lang.String... providedKeys)
static void	legalPropertyKeyValueArray(java.lang.Object... propertyKeyValues) Determines whether a list of key/values are legal, ensuring that there are an even number of values submitted and that the key values in the list of arguments are String or Element objects.
static java.util.Map<java.lang.String,Property>	propertyMap(Element element, java.lang.String... propertyKeys)
static java.util.Map<java.lang.String,java.lang.Object>	propertyValueMap(Element element, java.lang.String... propertyKeys)
static java.util.Optional<java.lang.Object[]>	remove(java.lang.String keyToRemove, java.lang.Object... keyValues) Remove a key from the set of key value pairs.
static java.util.Optional<java.lang.Object[]>	remove(T accessor, java.lang.Object... keyValues)
static java.lang.Object[]	upsert(java.lang.Object[] keyValues, java.lang.String key, java.lang.Object val) Append a key/value pair to a list of existing key/values.
static void	validateLabel(java.lang.String label) Determine whether the Element label can be legally set.
static void	validateProperty(java.lang.String key, java.lang.Object value) Determines whether the property key/value for the specified thing can be legally set.
static java.util.Map<java.lang.String,java.util.List<VertexProperty>>	vertexPropertyMap(Vertex vertex, java.lang.String... propertyKeys)
static java.util.Map<java.lang.String,java.util.List>	vertexPropertyValueMap(Vertex vertex, java.lang.String... propertyKeys)

Methods inherited from class java.lang.Object

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

Constructor Detail

ElementHelper

public ElementHelper()

Method Detail

validateLabel

public static void validateLabel(java.lang.String label)
                          throws java.lang.IllegalArgumentException

Determine whether the Element label can be legally set. This is typically used as a pre-condition check.

Parameters:

label - the element label

Throws:

java.lang.IllegalArgumentException - whether the label is legal and if not, a clear reason exception is provided

getOrAddVertex

public static Vertex getOrAddVertex(Graph graph,
                                    java.lang.Object id,
                                    java.lang.String label)

Check if the vertex, by ID, exists. If it does return it, else create it and return it.

Parameters:

graph - the graph to check for the existence of the vertex

id - the id of the vertex to look for

label - the label of the vertex to set if the vertex does not exist

Returns:

a pre-existing vertex or a newly created vertex

validateProperty

public static void validateProperty(java.lang.String key,
                                    java.lang.Object value)
                             throws java.lang.IllegalArgumentException

Determines whether the property key/value for the specified thing can be legally set. This is typically used as a pre-condition check prior to setting a property.

Parameters:

key - the key of the property

value - the value of the property

Throws:

java.lang.IllegalArgumentException - whether the key/value pair is legal and if not, a clear reason exception message is provided

legalPropertyKeyValueArray

public static void legalPropertyKeyValueArray(java.lang.Object... propertyKeyValues)
                                       throws java.lang.IllegalArgumentException

Determines whether a list of key/values are legal, ensuring that there are an even number of values submitted and that the key values in the list of arguments are String or Element objects.

Parameters:

propertyKeyValues - a list of key/value pairs

Throws:

java.lang.IllegalArgumentException - if something in the pairs is illegal

getIdValue

public static java.util.Optional<java.lang.Object> getIdValue(java.lang.Object... keyValues)

Extracts the value of the T.id key from the list of arguments.

Parameters:

keyValues - a list of key/value pairs

Returns:

the value associated with T.id

Throws:

java.lang.NullPointerException - if the value for the T.id key is null

remove

public static java.util.Optional<java.lang.Object[]> remove(java.lang.String keyToRemove,
                                                            java.lang.Object... keyValues)

Remove a key from the set of key value pairs. Assumes that validations have already taken place to assure that key positions contain strings and that there are an even number of elements. If after removal there are no values left, the key value list is returned as empty.

remove

public static java.util.Optional<java.lang.Object[]> remove(T accessor,
                                                            java.lang.Object... keyValues)

upsert

public static java.lang.Object[] upsert(java.lang.Object[] keyValues,
                                        java.lang.String key,
                                        java.lang.Object val)

Append a key/value pair to a list of existing key/values. If the key already exists in the keyValues then that value is overwritten with the provided value.

asMap

public static java.util.Map<java.lang.String,java.lang.Object> asMap(java.lang.Object... keyValues)

Converts a set of key values to a Map. Assumes that validations have already taken place to assure that key positions contain strings and that there are an even number of elements.

asPairs

public static java.util.List<org.javatuples.Pair<java.lang.String,java.lang.Object>> asPairs(java.lang.Object... keyValues)

Convert a set of key values to a list of Pair objects. Assumes that validations have already taken place to assure that key positions contain strings and that there are an even number of elements.

getKeys

public static java.util.Set<java.lang.String> getKeys(java.lang.Object... keyValues)

Gets the list of keys from the key values.

Parameters:

keyValues - a list of key/values pairs

getLabelValue

public static java.util.Optional<java.lang.String> getLabelValue(java.lang.Object... keyValues)

Extracts the value of the T.label key from the list of arguments.

Parameters:

keyValues - a list of key/value pairs

Returns:

the value associated with T.label

Throws:

java.lang.ClassCastException - if the value of the label is not a String

java.lang.NullPointerException - if the value for the T.label key is null

attachProperties

public static void attachProperties(Element element,
                                    java.lang.Object... propertyKeyValues)

Assign key/value pairs as properties to an Element. If the value of T.id or T.label is in the set of pairs, then they are ignored.

Parameters:

element - the graph element to assign the propertyKeyValues

propertyKeyValues - the key/value pairs to assign to the element

Throws:

java.lang.ClassCastException - if the value of the key is not a String

java.lang.IllegalArgumentException - if the value of element is null

attachSingleProperties

public static void attachSingleProperties(Vertex vertex,
                                          java.lang.Object... propertyKeyValues)

Assign key/value pairs as properties to an Vertex. If the value of T.id or T.label is in the set of pairs, then they are ignored.

Parameters:

vertex - the vertex to assign the propertyKeyValues

propertyKeyValues - the key/value pairs to assign to the vertex

Throws:

java.lang.ClassCastException - if the value of the key is not a String

java.lang.IllegalArgumentException - if the value of vertex is null

getProperties

public static java.lang.Object[] getProperties(Element element,
                                               boolean includeId,
                                               boolean includeLabel,
                                               java.util.Set<java.lang.String> propertiesToCopy)

Retrieve the properties associated with a particular element. The result is a Object[] where odd indices are String keys and even indices are the values.

Parameters:

element - the element to retrieve properties from

includeId - include Element.ID in the key/value list

includeLabel - include Element.LABEL in the key/value list

propertiesToCopy - the properties to include with an empty list meaning copy all properties

Returns:

a key/value array of properties where odd indices are String keys and even indices are the values.

areEqual

public static boolean areEqual(Element a,
                               java.lang.Object b)

A standard method for determining if two Element objects are equal. This method should be used by any Object.equals(Object) implementation to ensure consistent behavior. This method is used for Vertex, Edge, and VertexProperty.

Parameters:

a - The first Element

b - The second Element (as an Object)

Returns:

true if elements and equal and false otherwise

Throws:

java.lang.IllegalArgumentException - if either argument is null

areEqual

public static boolean areEqual(VertexProperty a,
                               java.lang.Object b)

A standard method for determining if two VertexProperty objects are equal. This method should be used by any Object.equals(Object) implementation to ensure consistent behavior.

Parameters:

a - the first VertexProperty

b - the second VertexProperty

Returns:

true if equal and false otherwise

haveEqualIds

public static boolean haveEqualIds(Element a,
                                   Element b)

Simply tests if the value returned from Element.id() are equal().

Parameters:

a - the first Element

b - the second Element

Returns:

true if ids are equal and false otherwise

hashCode

public static int hashCode(Element element)

If two Element instances are equal, then they must have the same hash codes. This methods ensures consistent hashCode values.

Parameters:

element - the element to get the hashCode for

Returns:

the hash code of the element

hashCode

public static int hashCode(Property property)

If two Property instances are equal, then they must have the same hash codes. This methods ensures consistent hashCode values. For VertexProperty use hashCode(com.tinkerpop.gremlin.structure.Element).

Parameters:

property - the property to get the hashCode for

Returns:

the hash code of the property

areEqual

public static boolean areEqual(Property a,
                               java.lang.Object b)

A standard method for determining if two Property objects are equal. This method should be used by any Object.equals(Object) implementation to ensure consistent behavior.

Parameters:

a - the first Property

b - the second Property

Returns:

true if equal and false otherwise

propertyValueMap

public static java.util.Map<java.lang.String,java.lang.Object> propertyValueMap(Element element,
                                                                                java.lang.String... propertyKeys)

propertyMap

public static java.util.Map<java.lang.String,Property> propertyMap(Element element,
                                                                   java.lang.String... propertyKeys)

vertexPropertyValueMap

public static java.util.Map<java.lang.String,java.util.List> vertexPropertyValueMap(Vertex vertex,
                                                                                    java.lang.String... propertyKeys)

vertexPropertyMap

public static java.util.Map<java.lang.String,java.util.List<VertexProperty>> vertexPropertyMap(Vertex vertex,
                                                                                               java.lang.String... propertyKeys)

keyExists

public static boolean keyExists(java.lang.String key,
                                java.lang.String... providedKeys)

idExists

public static boolean idExists(java.lang.Object id,
                               java.lang.Object... providedIds)