001/* 002 * Copyright (C) 2016 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.graph; 018 019import static com.google.common.base.Preconditions.checkArgument; 020import static com.google.common.base.Preconditions.checkNotNull; 021import static com.google.common.graph.Graphs.checkNonNegative; 022 023import com.google.common.annotations.Beta; 024import com.google.common.base.Optional; 025 026/** 027 * A builder for constructing instances of {@link MutableValueGraph} or {@link ImmutableValueGraph} 028 * with user-defined properties. 029 * 030 * <p>A graph built by this class will have the following properties by default: 031 * 032 * <ul> 033 * <li>does not allow self-loops 034 * <li>orders {@link Graph#nodes()} in the order in which the elements were added 035 * </ul> 036 * 037 * <p>Examples of use: 038 * 039 * <pre>{@code 040 * // Building a mutable value graph 041 * MutableValueGraph<String, Double> graph = 042 * ValueGraphBuilder.undirected().allowsSelfLoops(true).build(); 043 * graph.putEdgeValue("San Francisco", "San Francisco", 0.0); 044 * graph.putEdgeValue("San Jose", "San Jose", 0.0); 045 * graph.putEdgeValue("San Francisco", "San Jose", 48.4); 046 * 047 * // Building an immutable value graph 048 * ImmutableValueGraph<String, Double> immutableGraph = 049 * ValueGraphBuilder.undirected() 050 * .allowsSelfLoops(true) 051 * .<String, Double>immutable() 052 * .putEdgeValue("San Francisco", "San Francisco", 0.0) 053 * .putEdgeValue("San Jose", "San Jose", 0.0) 054 * .putEdgeValue("San Francisco", "San Jose", 48.4) 055 * .build(); 056 * }</pre> 057 * 058 * @author James Sexton 059 * @author Joshua O'Madadhain 060 * @param <N> The most general node type this builder will support. This is normally {@code Object} 061 * unless it is constrained by using a method like {@link #nodeOrder}, or the builder is 062 * constructed based on an existing {@code ValueGraph} using {@link #from(ValueGraph)}. 063 * @param <V> The most general value type this builder will support. This is normally {@code Object} 064 * unless the builder is constructed based on an existing {@code Graph} using {@link 065 * #from(ValueGraph)}. 066 * @since 20.0 067 */ 068@Beta 069@ElementTypesAreNonnullByDefault 070public final class ValueGraphBuilder<N, V> extends AbstractGraphBuilder<N> { 071 072 /** Creates a new instance with the specified edge directionality. */ 073 private ValueGraphBuilder(boolean directed) { 074 super(directed); 075 } 076 077 /** Returns a {@link ValueGraphBuilder} for building directed graphs. */ 078 public static ValueGraphBuilder<Object, Object> directed() { 079 return new ValueGraphBuilder<>(true); 080 } 081 082 /** Returns a {@link ValueGraphBuilder} for building undirected graphs. */ 083 public static ValueGraphBuilder<Object, Object> undirected() { 084 return new ValueGraphBuilder<>(false); 085 } 086 087 /** 088 * Returns a {@link ValueGraphBuilder} initialized with all properties queryable from {@code 089 * graph}. 090 * 091 * <p>The "queryable" properties are those that are exposed through the {@link ValueGraph} 092 * interface, such as {@link ValueGraph#isDirected()}. Other properties, such as {@link 093 * #expectedNodeCount(int)}, are not set in the new builder. 094 */ 095 public static <N, V> ValueGraphBuilder<N, V> from(ValueGraph<N, V> graph) { 096 return new ValueGraphBuilder<N, V>(graph.isDirected()) 097 .allowsSelfLoops(graph.allowsSelfLoops()) 098 .nodeOrder(graph.nodeOrder()) 099 .incidentEdgeOrder(graph.incidentEdgeOrder()); 100 } 101 102 /** 103 * Returns an {@link ImmutableValueGraph.Builder} with the properties of this {@link 104 * ValueGraphBuilder}. 105 * 106 * <p>The returned builder can be used for populating an {@link ImmutableValueGraph}. 107 * 108 * <p>Note that the returned builder will always have {@link #incidentEdgeOrder} set to {@link 109 * ElementOrder#stable()}, regardless of the value that was set in this builder. 110 * 111 * @since 28.0 112 */ 113 public <N1 extends N, V1 extends V> ImmutableValueGraph.Builder<N1, V1> immutable() { 114 ValueGraphBuilder<N1, V1> castBuilder = cast(); 115 return new ImmutableValueGraph.Builder<>(castBuilder); 116 } 117 118 /** 119 * Specifies whether the graph will allow self-loops (edges that connect a node to itself). 120 * Attempting to add a self-loop to a graph that does not allow them will throw an {@link 121 * UnsupportedOperationException}. 122 * 123 * <p>The default value is {@code false}. 124 */ 125 public ValueGraphBuilder<N, V> allowsSelfLoops(boolean allowsSelfLoops) { 126 this.allowsSelfLoops = allowsSelfLoops; 127 return this; 128 } 129 130 /** 131 * Specifies the expected number of nodes in the graph. 132 * 133 * @throws IllegalArgumentException if {@code expectedNodeCount} is negative 134 */ 135 public ValueGraphBuilder<N, V> expectedNodeCount(int expectedNodeCount) { 136 this.expectedNodeCount = Optional.of(checkNonNegative(expectedNodeCount)); 137 return this; 138 } 139 140 /** 141 * Specifies the order of iteration for the elements of {@link Graph#nodes()}. 142 * 143 * <p>The default value is {@link ElementOrder#insertion() insertion order}. 144 */ 145 public <N1 extends N> ValueGraphBuilder<N1, V> nodeOrder(ElementOrder<N1> nodeOrder) { 146 ValueGraphBuilder<N1, V> newBuilder = cast(); 147 newBuilder.nodeOrder = checkNotNull(nodeOrder); 148 return newBuilder; 149 } 150 151 /** 152 * Specifies the order of iteration for the elements of {@link ValueGraph#edges()}, {@link 153 * ValueGraph#adjacentNodes(Object)}, {@link ValueGraph#predecessors(Object)}, {@link 154 * ValueGraph#successors(Object)} and {@link ValueGraph#incidentEdges(Object)}. 155 * 156 * <p>The default value is {@link ElementOrder#unordered() unordered} for mutable graphs. For 157 * immutable graphs, this value is ignored; they always have a {@link ElementOrder#stable() 158 * stable} order. 159 * 160 * @throws IllegalArgumentException if {@code incidentEdgeOrder} is not either {@code 161 * ElementOrder.unordered()} or {@code ElementOrder.stable()}. 162 * @since 29.0 163 */ 164 public <N1 extends N> ValueGraphBuilder<N1, V> incidentEdgeOrder( 165 ElementOrder<N1> incidentEdgeOrder) { 166 checkArgument( 167 incidentEdgeOrder.type() == ElementOrder.Type.UNORDERED 168 || incidentEdgeOrder.type() == ElementOrder.Type.STABLE, 169 "The given elementOrder (%s) is unsupported. incidentEdgeOrder() only supports" 170 + " ElementOrder.unordered() and ElementOrder.stable().", 171 incidentEdgeOrder); 172 ValueGraphBuilder<N1, V> newBuilder = cast(); 173 newBuilder.incidentEdgeOrder = checkNotNull(incidentEdgeOrder); 174 return newBuilder; 175 } 176 /** 177 * Returns an empty {@link MutableValueGraph} with the properties of this {@link 178 * ValueGraphBuilder}. 179 */ 180 public <N1 extends N, V1 extends V> MutableValueGraph<N1, V1> build() { 181 return new StandardMutableValueGraph<>(this); 182 } 183 184 ValueGraphBuilder<N, V> copy() { 185 ValueGraphBuilder<N, V> newBuilder = new ValueGraphBuilder<>(directed); 186 newBuilder.allowsSelfLoops = allowsSelfLoops; 187 newBuilder.nodeOrder = nodeOrder; 188 newBuilder.expectedNodeCount = expectedNodeCount; 189 newBuilder.incidentEdgeOrder = incidentEdgeOrder; 190 return newBuilder; 191 } 192 193 @SuppressWarnings("unchecked") 194 private <N1 extends N, V1 extends V> ValueGraphBuilder<N1, V1> cast() { 195 return (ValueGraphBuilder<N1, V1>) this; 196 } 197}