com.datastax.dse.driver.api.core.graph.GraphNode Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.datastax.dse.driver.api.core.graph;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.tinkerpop.gremlin.process.traversal.Path;
import org.apache.tinkerpop.gremlin.structure.Edge;
import org.apache.tinkerpop.gremlin.structure.Property;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;
/**
* A node in a tree-like structure representing a Graph or a Graph component.
*
* It can be:
*
*
* - a scalar value of a primitive type (boolean, string, int, long, double);
*
- a graph element (vertex, edge, path or property);
*
- a list of nodes;
*
- a set of nodes;
*
- a map of nodes.
*
*
* This interface provides test methods to find out what a node represents, and conversion methods
* to cast it to a particular Java type. Two generic methods {@link #as(Class)} and {@link
* #as(GenericType)} can produce any arbitrary Java type, provided that the underlying serialization
* runtime has been correctly configured to support the requested conversion.
*/
public interface GraphNode {
/** Whether this node represents a {@code null} value. */
boolean isNull();
/**
* Returns {@code true} if this node is a {@link Map}, and {@code false} otherwise.
*
* If this method returns {@code true}, you can convert this node with {@link #asMap()}, or use
* {@link #keys()} and {@link #getByKey(Object)} to access the individual fields (note that
* entries are not ordered, so {@link #getByIndex(int)} does not work).
*/
boolean isMap();
/** The keys of this map node, or an empty iterator if it is not a map. */
Iterable keys();
/**
* Returns the value for the given key as a node.
*
*
If this node is not a map, or does not contain the specified key, {@code null} is returned.
*
*
If the property value has been explicitly set to {@code null}, implementors may return a
* special "null node" instead of {@code null}.
*/
GraphNode getByKey(Object key);
/** Deserializes and returns this node as a {@link Map}. */
Map asMap();
/**
* Returns {@code true} if this node is a {@link List}, and {@code false} otherwise.
*
* If this method returns {@code true}, you can convert this node with {@link #asList()}, or
* use {@link #size()} and {@link #getByIndex(int)} to access the individual fields.
*/
boolean isList();
/** The size of the current node, if it is a list or map, or {@code 0} otherwise. */
int size();
/**
* Returns the element at the given index as a node.
*
*
If this node is not a list, or {@code index} is out of bounds (i.e. less than zero or {@code
* >= size()}, {@code null} is returned; no exception will be thrown.
*
*
If the requested element has been explicitly set to {@code null}, implementors may return a
* special "null node" instead of {@code null}.
*/
GraphNode getByIndex(int index);
/** Deserializes and returns this node as a {@link List}. */
List asList();
/**
* Returns {@code true} if this node is a simple scalar value, (i.e., string, boolean or number),
* and {@code false} otherwise.
*
* If this method returns {@code true}, you can convert this node with {@link #asString()},
* {@link #asBoolean()}, {@link #asInt()}, {@link #asLong()} or {@link #asDouble()}.
*/
boolean isValue();
/**
* Returns this node as an integer.
*
*
If the underlying object is not convertible to integer, implementors may choose to either
* throw {@link ClassCastException} or return [null | empty | some default value], whichever is
* deemed more appropriate.
*/
int asInt();
/**
* Returns this node as a boolean.
*
*
If the underlying object is not convertible to boolean, implementors may choose to either
* throw {@link ClassCastException} or return [null | empty | some default value], whichever is
* deemed more appropriate.
*/
boolean asBoolean();
/**
* Returns this node as a long integer.
*
*
If the underlying object is not convertible to long, implementors may choose to either throw
* {@link ClassCastException} or return [null | empty | some default value], whichever is deemed
* more appropriate.
*/
long asLong();
/**
* Returns this node as a long integer.
*
*
If the underlying object is not convertible to double, implementors may choose to either
* throw {@link ClassCastException} or return [null | empty | some default value], whichever is
* deemed more appropriate.
*/
double asDouble();
/**
* A valid string representation of this node.
*
*
If the underlying object is not convertible to a string, implementors may choose to either
* throw {@link ClassCastException} or return an empty string, whichever is deemed more
* appropriate.
*/
String asString();
/**
* Deserializes and returns this node as an instance of {@code clazz}.
*
*
Before attempting such a conversion, there must be an appropriate converter configured on
* the underlying serialization runtime.
*/
ResultT as(Class clazz);
/**
* Deserializes and returns this node as an instance of the given {@link GenericType type}.
*
* Before attempting such a conversion, there must be an appropriate converter configured on
* the underlying serialization runtime.
*/
ResultT as(GenericType type);
/**
* Returns {@code true} if this node is a {@link Vertex}, and {@code false} otherwise.
*
* If this method returns {@code true}, then {@link #asVertex()} can be safely called.
*/
boolean isVertex();
/** Returns this node as a Tinkerpop {@link Vertex}. */
Vertex asVertex();
/**
* Returns {@code true} if this node is a {@link Edge}, and {@code false} otherwise.
*
*
If this method returns {@code true}, then {@link #asEdge()} can be safely called.
*/
boolean isEdge();
/** Returns this node as a Tinkerpop {@link Edge}. */
Edge asEdge();
/**
* Returns {@code true} if this node is a {@link Path}, and {@code false} otherwise.
*
*
If this method returns {@code true}, then {@link #asPath()} can be safely called.
*/
boolean isPath();
/** Returns this node as a Tinkerpop {@link Path}. */
Path asPath();
/**
* Returns {@code true} if this node is a {@link Property}, and {@code false} otherwise.
*
*
If this method returns {@code true}, then {@link #asProperty()} can be safely called.
*/
boolean isProperty();
/** Returns this node as a Tinkerpop {@link Property}. */
Property asProperty();
/**
* Returns {@code true} if this node is a {@link VertexProperty}, and {@code false} otherwise.
*
* If this method returns {@code true}, then {@link #asVertexProperty()} ()} can be safely
* called.
*/
boolean isVertexProperty();
/** Returns this node as a Tinkerpop {@link VertexProperty}. */
VertexProperty asVertexProperty();
/**
* Returns {@code true} if this node is a {@link Set}, and {@code false} otherwise.
*
* If this method returns {@code true}, you can convert this node with {@link #asSet()}, or use
* {@link #size()}.
*/
boolean isSet();
/** Deserializes and returns this node as a {@link Set}. */
Set asSet();
}