--- /dev/null
+/*
+ * Copyright (c) 2009, the JUNG Project and the Regents of the University
+ * of California
+ * All rights reserved.
+ *
+ * This software is open-source under the BSD license; see either
+ * "license.txt" or
+ * http://jung.sourceforge.net/license.txt for a description.
+ */
+
+package edu.uci.ics.jung.algorithms.generators;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.collections15.Factory;
+
+import edu.uci.ics.jung.graph.Graph;
+import edu.uci.ics.jung.graph.util.EdgeType;
+
+/**
+ * Simple generator of an m x n lattice where each vertex
+ * is incident with each of its neighbors (to the left, right, up, and down).
+ * May be toroidal, in which case the vertices on the edges are connected to
+ * their counterparts on the opposite edges as well.
+ *
+ * <p>If the graph factory supplied has a default edge type of {@code EdgeType.DIRECTED},
+ * then edges will be created in both directions between adjacent vertices.
+ *
+ * @author Joshua O'Madadhain
+ */
+public class Lattice2DGenerator<V,E> implements GraphGenerator<V,E>
+{
+ protected int row_count;
+ protected int col_count;
+ protected boolean is_toroidal;
+ protected boolean is_directed;
+ protected Factory<? extends Graph<V, E>> graph_factory;
+ protected Factory<V> vertex_factory;
+ protected Factory<E> edge_factory;
+ private List<V> v_array;
+
+ /**
+ * Constructs a generator of square lattices of size {@code latticeSize}
+ * with the specified parameters.
+ *
+ * @param graph_factory used to create the {@code Graph} for the lattice
+ * @param vertex_factory used to create the lattice vertices
+ * @param edge_factory used to create the lattice edges
+ * @param latticeSize the number of rows and columns of the lattice
+ * @param isToroidal if true, the created lattice wraps from top to bottom and left to right
+ */
+ public Lattice2DGenerator(Factory<? extends Graph<V,E>> graph_factory, Factory<V> vertex_factory,
+ Factory<E> edge_factory, int latticeSize, boolean isToroidal)
+ {
+ this(graph_factory, vertex_factory, edge_factory, latticeSize, latticeSize, isToroidal);
+ }
+
+ /**
+ * Creates a generator of {@code row_count} x {@code col_count} lattices
+ * with the specified parameters.
+ *
+ * @param graph_factory used to create the {@code Graph} for the lattice
+ * @param vertex_factory used to create the lattice vertices
+ * @param edge_factory used to create the lattice edges
+ * @param row_count the number of rows in the lattice
+ * @param col_count the number of columns in the lattice
+ * @param isToroidal if true, the created lattice wraps from top to bottom and left to right
+ */
+ public Lattice2DGenerator(Factory<? extends Graph<V,E>> graph_factory, Factory<V> vertex_factory,
+ Factory<E> edge_factory, int row_count, int col_count, boolean isToroidal)
+ {
+ if (row_count < 2 || col_count < 2)
+ {
+ throw new IllegalArgumentException("Row and column counts must each be at least 2.");
+ }
+
+ this.row_count = row_count;
+ this.col_count = col_count;
+ this.is_toroidal = isToroidal;
+ this.graph_factory = graph_factory;
+ this.vertex_factory = vertex_factory;
+ this.edge_factory = edge_factory;
+ this.is_directed = (graph_factory.create().getDefaultEdgeType() == EdgeType.DIRECTED);
+ }
+
+ /**
+ * @see edu.uci.ics.jung.algorithms.generators.GraphGenerator#create()
+ */
+ @SuppressWarnings("unchecked")
+ public Graph<V,E> create()
+ {
+ int vertex_count = row_count * col_count;
+ Graph<V,E> graph = graph_factory.create();
+ v_array = new ArrayList<V>(vertex_count);
+ for (int i = 0; i < vertex_count; i++)
+ {
+ V v = vertex_factory.create();
+ graph.addVertex(v);
+ v_array.add(i, v);
+ }
+
+ int start = is_toroidal ? 0 : 1;
+ int end_row = is_toroidal ? row_count : row_count - 1;
+ int end_col = is_toroidal ? col_count : col_count - 1;
+
+ // fill in edges
+ // down
+ for (int i = 0; i < end_row; i++)
+ for (int j = 0; j < col_count; j++)
+ graph.addEdge(edge_factory.create(), getVertex(i,j), getVertex(i+1, j));
+ // right
+ for (int i = 0; i < row_count; i++)
+ for (int j = 0; j < end_col; j++)
+ graph.addEdge(edge_factory.create(), getVertex(i,j), getVertex(i, j+1));
+
+ // if the graph is directed, fill in the edges going the other direction...
+ if (graph.getDefaultEdgeType() == EdgeType.DIRECTED)
+ {
+ // up
+ for (int i = start; i < row_count; i++)
+ for (int j = 0; j < col_count; j++)
+ graph.addEdge(edge_factory.create(), getVertex(i,j), getVertex(i-1, j));
+ // left
+ for (int i = 0; i < row_count; i++)
+ for (int j = start; j < col_count; j++)
+ graph.addEdge(edge_factory.create(), getVertex(i,j), getVertex(i, j-1));
+ }
+
+ return graph;
+ }
+
+ /**
+ * Returns the number of edges found in a lattice of this generator's specifications.
+ * (This is useful for subclasses that may modify the generated graphs to add more edges.)
+ */
+ public int getGridEdgeCount()
+ {
+ int boundary_adjustment = (is_toroidal ? 0 : 1);
+ int vertical_edge_count = col_count * (row_count - boundary_adjustment);
+ int horizontal_edge_count = row_count * (col_count - boundary_adjustment);
+
+ return (vertical_edge_count + horizontal_edge_count) * (is_directed ? 2 : 1);
+ }
+
+ protected int getIndex(int i, int j)
+ {
+ return ((mod(i, row_count)) * col_count) + (mod(j, col_count));
+ }
+
+ protected int mod(int i, int modulus)
+ {
+ int i_mod = i % modulus;
+ return i_mod >= 0 ? i_mod : i_mod + modulus;
+ }
+
+ /**
+ * Returns the vertex at position ({@code i mod row_count, j mod col_count}).
+ */
+ protected V getVertex(int i, int j)
+ {
+ return v_array.get(getIndex(i, j));
+ }
+
+ /**
+ * Returns the {@code i}th vertex (counting row-wise).
+ */
+ protected V getVertex(int i)
+ {
+ return v_array.get(i);
+ }
+
+ /**
+ * Returns the row in which vertex {@code i} is found.
+ */
+ protected int getRow(int i)
+ {
+ return i / row_count;
+ }
+
+ /**
+ * Returns the column in which vertex {@code i} is found.
+ */
+ protected int getCol(int i)
+ {
+ return i % col_count;
+ }
+}
Code Review / controller.git / blobdiff