com.facebook.presto.jdbc.internal.guava.graph.ImmutableGraph Maven / Gradle / Ivy
/*
* Copyright (C) 2014 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.base.Functions;
import com.facebook.presto.jdbc.internal.guava.collect.ImmutableMap;
import com.facebook.presto.jdbc.internal.guava.collect.Maps;
import com.facebook.presto.jdbc.internal.guava.graph.GraphConstants.Presence;
import com.google.errorprone.annotations.Immutable;
/**
* A {@link Graph} whose elements and structural relationships will never change. Instances of this
* class may be obtained with {@link #copyOf(Graph)}.
*
* 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
* @author Joshua O'Madadhain
* @author Omar Darwish
* @param Node parameter type
* @since 20.0
*/
@Beta
@Immutable(containerOf = {"N"})
public class ImmutableGraph extends ForwardingGraph {
@SuppressWarnings("Immutable") // The backing graph must be immutable.
private final BaseGraph backingGraph;
ImmutableGraph(BaseGraph backingGraph) {
this.backingGraph = backingGraph;
}
/** Returns an immutable copy of {@code graph}. */
public static ImmutableGraph copyOf(Graph graph) {
return (graph instanceof ImmutableGraph)
? (ImmutableGraph) graph
: new ImmutableGraph(
new ConfigurableValueGraph(
GraphBuilder.from(graph), getNodeConnections(graph), graph.edges().size()));
}
/**
* Simply returns its argument.
*
* @deprecated no need to use this
*/
@Deprecated
public static ImmutableGraph copyOf(ImmutableGraph graph) {
return checkNotNull(graph);
}
private static ImmutableMap> getNodeConnections(
Graph 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(Graph graph, N node) {
Function edgeValueFn = Functions.constant(Presence.EDGE_EXISTS);
return graph.isDirected()
? DirectedGraphConnections.ofImmutable(
graph.predecessors(node), Maps.asMap(graph.successors(node), edgeValueFn))
: UndirectedGraphConnections.ofImmutable(
Maps.asMap(graph.adjacentNodes(node), edgeValueFn));
}
@Override
protected BaseGraph delegate() {
return backingGraph;
}
}