| /* |
| * 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.google.common.graph; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.graph.Graphs.checkNonNegative; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.base.Optional; |
| |
| /** |
| * A builder for constructing instances of {@link MutableNetwork} or {@link ImmutableNetwork} with |
| * user-defined properties. |
| * |
| * <p>A network built by this class will have the following properties by default: |
| * |
| * <ul> |
| * <li>does not allow parallel edges |
| * <li>does not allow self-loops |
| * <li>orders {@link Network#nodes()} and {@link Network#edges()} in the order in which the |
| * elements were added |
| * </ul> |
| * |
| * <p>Examples of use: |
| * |
| * <pre>{@code |
| * // Building a mutable network |
| * MutableNetwork<String, Integer> network = |
| * NetworkBuilder.directed().allowsParallelEdges(true).build(); |
| * flightNetwork.addEdge("LAX", "ATL", 3025); |
| * flightNetwork.addEdge("LAX", "ATL", 1598); |
| * flightNetwork.addEdge("ATL", "LAX", 2450); |
| * |
| * // Building a immutable network |
| * ImmutableNetwork<String, Integer> immutableNetwork = |
| * NetworkBuilder.directed() |
| * .allowsParallelEdges(true) |
| * .<String, Integer>immutable() |
| * .addEdge("LAX", "ATL", 3025) |
| * .addEdge("LAX", "ATL", 1598) |
| * .addEdge("ATL", "LAX", 2450) |
| * .build(); |
| * }</pre> |
| * |
| * @author James Sexton |
| * @author Joshua O'Madadhain |
| * @param <N> The most general node type this builder will support. This is normally {@code Object} |
| * unless it is constrained by using a method like {@link #nodeOrder}, or the builder is |
| * constructed based on an existing {@code Network} using {@link #from(Network)}. |
| * @param <E> The most general edge type this builder will support. This is normally {@code Object} |
| * unless it is constrained by using a method like {@link #edgeOrder}, or the builder is |
| * constructed based on an existing {@code Network} using {@link #from(Network)}. |
| * @since 20.0 |
| */ |
| @Beta |
| public final class NetworkBuilder<N, E> extends AbstractGraphBuilder<N> { |
| boolean allowsParallelEdges = false; |
| ElementOrder<? super E> edgeOrder = ElementOrder.insertion(); |
| Optional<Integer> expectedEdgeCount = Optional.absent(); |
| |
| /** Creates a new instance with the specified edge directionality. */ |
| private NetworkBuilder(boolean directed) { |
| super(directed); |
| } |
| |
| /** Returns a {@link NetworkBuilder} for building directed networks. */ |
| public static NetworkBuilder<Object, Object> directed() { |
| return new NetworkBuilder<>(true); |
| } |
| |
| /** Returns a {@link NetworkBuilder} for building undirected networks. */ |
| public static NetworkBuilder<Object, Object> undirected() { |
| return new NetworkBuilder<>(false); |
| } |
| |
| /** |
| * Returns a {@link NetworkBuilder} initialized with all properties queryable from {@code |
| * network}. |
| * |
| * <p>The "queryable" properties are those that are exposed through the {@link Network} interface, |
| * such as {@link Network#isDirected()}. Other properties, such as {@link |
| * #expectedNodeCount(int)}, are not set in the new builder. |
| */ |
| public static <N, E> NetworkBuilder<N, E> from(Network<N, E> network) { |
| return new NetworkBuilder<N, E>(network.isDirected()) |
| .allowsParallelEdges(network.allowsParallelEdges()) |
| .allowsSelfLoops(network.allowsSelfLoops()) |
| .nodeOrder(network.nodeOrder()) |
| .edgeOrder(network.edgeOrder()); |
| } |
| |
| /** |
| * Returns an {@link ImmutableNetwork.Builder} with the properties of this {@link NetworkBuilder}. |
| * |
| * <p>The returned builder can be used for populating an {@link ImmutableNetwork}. |
| * |
| * @since 28.0 |
| */ |
| public <N1 extends N, E1 extends E> ImmutableNetwork.Builder<N1, E1> immutable() { |
| NetworkBuilder<N1, E1> castBuilder = cast(); |
| return new ImmutableNetwork.Builder<>(castBuilder); |
| } |
| |
| /** |
| * Specifies whether the network will allow parallel edges. Attempting to add a parallel edge to a |
| * network that does not allow them will throw an {@link UnsupportedOperationException}. |
| * |
| * <p>The default value is {@code false}. |
| */ |
| public NetworkBuilder<N, E> allowsParallelEdges(boolean allowsParallelEdges) { |
| this.allowsParallelEdges = allowsParallelEdges; |
| return this; |
| } |
| |
| /** |
| * Specifies whether the network will allow self-loops (edges that connect a node to itself). |
| * Attempting to add a self-loop to a network that does not allow them will throw an {@link |
| * UnsupportedOperationException}. |
| * |
| * <p>The default value is {@code false}. |
| */ |
| public NetworkBuilder<N, E> allowsSelfLoops(boolean allowsSelfLoops) { |
| this.allowsSelfLoops = allowsSelfLoops; |
| return this; |
| } |
| |
| /** |
| * Specifies the expected number of nodes in the network. |
| * |
| * @throws IllegalArgumentException if {@code expectedNodeCount} is negative |
| */ |
| public NetworkBuilder<N, E> expectedNodeCount(int expectedNodeCount) { |
| this.expectedNodeCount = Optional.of(checkNonNegative(expectedNodeCount)); |
| return this; |
| } |
| |
| /** |
| * Specifies the expected number of edges in the network. |
| * |
| * @throws IllegalArgumentException if {@code expectedEdgeCount} is negative |
| */ |
| public NetworkBuilder<N, E> expectedEdgeCount(int expectedEdgeCount) { |
| this.expectedEdgeCount = Optional.of(checkNonNegative(expectedEdgeCount)); |
| return this; |
| } |
| |
| /** |
| * Specifies the order of iteration for the elements of {@link Network#nodes()}. |
| * |
| * <p>The default value is {@link ElementOrder#insertion() insertion order}. |
| */ |
| public <N1 extends N> NetworkBuilder<N1, E> nodeOrder(ElementOrder<N1> nodeOrder) { |
| NetworkBuilder<N1, E> newBuilder = cast(); |
| newBuilder.nodeOrder = checkNotNull(nodeOrder); |
| return newBuilder; |
| } |
| |
| /** |
| * Specifies the order of iteration for the elements of {@link Network#edges()}. |
| * |
| * <p>The default value is {@link ElementOrder#insertion() insertion order}. |
| */ |
| public <E1 extends E> NetworkBuilder<N, E1> edgeOrder(ElementOrder<E1> edgeOrder) { |
| NetworkBuilder<N, E1> newBuilder = cast(); |
| newBuilder.edgeOrder = checkNotNull(edgeOrder); |
| return newBuilder; |
| } |
| |
| /** Returns an empty {@link MutableNetwork} with the properties of this {@link NetworkBuilder}. */ |
| public <N1 extends N, E1 extends E> MutableNetwork<N1, E1> build() { |
| return new StandardMutableNetwork<>(this); |
| } |
| |
| @SuppressWarnings("unchecked") |
| private <N1 extends N, E1 extends E> NetworkBuilder<N1, E1> cast() { |
| return (NetworkBuilder<N1, E1>) this; |
| } |
| } |