com.facebook.presto.jdbc.internal.guava.graph.ImmutableValueGraph Maven / Gradle / Ivy
/*
* Copyright (C) 2016 The Guava Authors
*
* Licensed 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.facebook.presto.jdbc.internal.guava.graph;
import static com.facebook.presto.jdbc.internal.guava.base.Preconditions.checkNotNull;
import com.facebook.presto.jdbc.internal.guava.annotations.Beta;
import com.facebook.presto.jdbc.internal.guava.base.Function;
import com.facebook.presto.jdbc.internal.guava.collect.ImmutableMap;
import com.facebook.presto.jdbc.internal.guava.collect.Maps;
import com.google.errorprone.annotations.Immutable;
/**
* A {@link ValueGraph} whose elements and structural relationships will never change. Instances of
* this class may be obtained with {@link #copyOf(ValueGraph)}.
*
* See the Guava User's Guide's discussion
* of the {@code Immutable*} types for more information on the properties and guarantees
* provided by this class.
*
* @author James Sexton
* @param Node parameter type
* @param Value parameter type
* @since 20.0
*/
@Beta
@Immutable(containerOf = {"N", "V"})
@SuppressWarnings("Immutable") // Extends ConfigurableValueGraph but uses ImmutableMaps.
public final class ImmutableValueGraph extends ConfigurableValueGraph {
private ImmutableValueGraph(ValueGraph graph) {
super(ValueGraphBuilder.from(graph), getNodeConnections(graph), graph.edges().size());
}
/** Returns an immutable copy of {@code graph}. */
public static ImmutableValueGraph copyOf(ValueGraph graph) {
return (graph instanceof ImmutableValueGraph)
? (ImmutableValueGraph) graph
: new ImmutableValueGraph(graph);
}
/**
* Simply returns its argument.
*
* @deprecated no need to use this
*/
@Deprecated
public static ImmutableValueGraph copyOf(ImmutableValueGraph graph) {
return checkNotNull(graph);
}
@Override
public ImmutableGraph asGraph() {
return new ImmutableGraph(this); // safe because the view is effectively immutable
}
private static ImmutableMap> getNodeConnections(
ValueGraph graph) {
// ImmutableMap.Builder maintains the order of the elements as inserted, so the map will have
// whatever ordering the graph's nodes do, so ImmutableSortedMap is unnecessary even if the
// input nodes are sorted.
ImmutableMap.Builder> nodeConnections = ImmutableMap.builder();
for (N node : graph.nodes()) {
nodeConnections.put(node, connectionsOf(graph, node));
}
return nodeConnections.build();
}
private static GraphConnections connectionsOf(
final ValueGraph graph, final N node) {
Function successorNodeToValueFn =
new Function() {
@Override
public V apply(N successorNode) {
return graph.edgeValueOrDefault(node, successorNode, null);
}
};
return graph.isDirected()
? DirectedGraphConnections.ofImmutable(
graph.predecessors(node), Maps.asMap(graph.successors(node), successorNodeToValueFn))
: UndirectedGraphConnections.ofImmutable(
Maps.asMap(graph.adjacentNodes(node), successorNodeToValueFn));
}
}