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/*
 * 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.checkArgument;
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 MutableValueGraph} or {@link ImmutableValueGraph}
 * with user-defined properties.
 *
 * 

A graph built by this class will have the following properties by default: * *

    *
  • does not allow self-loops *
  • orders {@link Graph#nodes()} in the order in which the elements were added *
* *

Examples of use: * *

{@code
 * // Building a mutable value graph
 * MutableValueGraph graph =
 *     ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
 * graph.putEdgeValue("San Francisco", "San Francisco", 0.0);
 * graph.putEdgeValue("San Jose", "San Jose", 0.0);
 * graph.putEdgeValue("San Francisco", "San Jose", 48.4);
 *
 * // Building an immutable value graph
 * ImmutableValueGraph immutableGraph =
 *     ValueGraphBuilder.undirected()
 *         .allowsSelfLoops(true)
 *         .immutable()
 *         .putEdgeValue("San Francisco", "San Francisco", 0.0)
 *         .putEdgeValue("San Jose", "San Jose", 0.0)
 *         .putEdgeValue("San Francisco", "San Jose", 48.4)
 *         .build();
 * }
* * @author James Sexton * @author Joshua O'Madadhain * @param 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 ValueGraph} using {@link #from(ValueGraph)}. * @param The most general value type this builder will support. This is normally {@code Object} * unless the builder is constructed based on an existing {@code Graph} using {@link * #from(ValueGraph)}. * @since 20.0 */ @Beta public final class ValueGraphBuilder extends AbstractGraphBuilder { /** Creates a new instance with the specified edge directionality. */ private ValueGraphBuilder(boolean directed) { super(directed); } /** Returns a {@link ValueGraphBuilder} for building directed graphs. */ public static ValueGraphBuilder directed() { return new ValueGraphBuilder<>(true); } /** Returns a {@link ValueGraphBuilder} for building undirected graphs. */ public static ValueGraphBuilder undirected() { return new ValueGraphBuilder<>(false); } /** * Returns a {@link ValueGraphBuilder} initialized with all properties queryable from {@code * graph}. * *

The "queryable" properties are those that are exposed through the {@link ValueGraph} * interface, such as {@link ValueGraph#isDirected()}. Other properties, such as {@link * #expectedNodeCount(int)}, are not set in the new builder. */ public static ValueGraphBuilder from(ValueGraph graph) { return new ValueGraphBuilder(graph.isDirected()) .allowsSelfLoops(graph.allowsSelfLoops()) .nodeOrder(graph.nodeOrder()) .incidentEdgeOrder(graph.incidentEdgeOrder()); } /** * Returns an {@link ImmutableValueGraph.Builder} with the properties of this {@link * ValueGraphBuilder}. * *

The returned builder can be used for populating an {@link ImmutableValueGraph}. * *

Note that the returned builder will always have {@link #incidentEdgeOrder} set to {@link * ElementOrder#stable()}, regardless of the value that was set in this builder. * * @since 28.0 */ public ImmutableValueGraph.Builder immutable() { ValueGraphBuilder castBuilder = cast(); return new ImmutableValueGraph.Builder<>(castBuilder); } /** * Specifies whether the graph will allow self-loops (edges that connect a node to itself). * Attempting to add a self-loop to a graph that does not allow them will throw an {@link * UnsupportedOperationException}. * *

The default value is {@code false}. */ public ValueGraphBuilder allowsSelfLoops(boolean allowsSelfLoops) { this.allowsSelfLoops = allowsSelfLoops; return this; } /** * Specifies the expected number of nodes in the graph. * * @throws IllegalArgumentException if {@code expectedNodeCount} is negative */ public ValueGraphBuilder expectedNodeCount(int expectedNodeCount) { this.expectedNodeCount = Optional.of(checkNonNegative(expectedNodeCount)); return this; } /** * Specifies the order of iteration for the elements of {@link Graph#nodes()}. * *

The default value is {@link ElementOrder#insertion() insertion order}. */ public ValueGraphBuilder nodeOrder(ElementOrder nodeOrder) { ValueGraphBuilder newBuilder = cast(); newBuilder.nodeOrder = checkNotNull(nodeOrder); return newBuilder; } /** * Specifies the order of iteration for the elements of {@link ValueGraph#edges()}, {@link * ValueGraph#adjacentNodes(Object)}, {@link ValueGraph#predecessors(Object)}, {@link * ValueGraph#successors(Object)} and {@link ValueGraph#incidentEdges(Object)}. * *

The default value is {@link ElementOrder#unordered() unordered} for mutable graphs. For * immutable graphs, this value is ignored; they always have a {@link ElementOrder#stable() * stable} order. * * @throws IllegalArgumentException if {@code incidentEdgeOrder} is not either {@code * ElementOrder.unordered()} or {@code ElementOrder.stable()}. * @since 29.0 */ public ValueGraphBuilder incidentEdgeOrder( ElementOrder incidentEdgeOrder) { checkArgument( incidentEdgeOrder.type() == ElementOrder.Type.UNORDERED || incidentEdgeOrder.type() == ElementOrder.Type.STABLE, "The given elementOrder (%s) is unsupported. incidentEdgeOrder() only supports" + " ElementOrder.unordered() and ElementOrder.stable().", incidentEdgeOrder); ValueGraphBuilder newBuilder = cast(); newBuilder.incidentEdgeOrder = checkNotNull(incidentEdgeOrder); return newBuilder; } /** * Returns an empty {@link MutableValueGraph} with the properties of this {@link * ValueGraphBuilder}. */ public MutableValueGraph build() { return new StandardMutableValueGraph<>(this); } ValueGraphBuilder copy() { ValueGraphBuilder newBuilder = new ValueGraphBuilder<>(directed); newBuilder.allowsSelfLoops = allowsSelfLoops; newBuilder.nodeOrder = nodeOrder; newBuilder.expectedNodeCount = expectedNodeCount; newBuilder.incidentEdgeOrder = incidentEdgeOrder; return newBuilder; } @SuppressWarnings("unchecked") private ValueGraphBuilder cast() { return (ValueGraphBuilder) this; } }





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