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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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 org.apache.calcite.example.maze;
import org.apache.calcite.DataContext;
import org.apache.calcite.linq4j.AbstractEnumerable;
import org.apache.calcite.linq4j.Enumerable;
import org.apache.calcite.linq4j.Enumerator;
import org.apache.calcite.linq4j.Linq4j;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
import org.apache.calcite.schema.ScannableTable;
import org.apache.calcite.schema.impl.AbstractTable;
import org.apache.calcite.sql.type.SqlTypeName;
import org.apache.calcite.util.Util;
import java.io.PrintWriter;
import java.util.Random;
import java.util.Set;
/**
* User-defined table function that generates a Maze and prints it in text
* form.
*/
public class MazeTable extends AbstractTable implements ScannableTable {
final int width;
final int height;
final int seed;
final boolean solution;
private MazeTable(int width, int height, int seed, boolean solution) {
this.width = width;
this.height = height;
this.seed = seed;
this.solution = solution;
}
/** Table function that generates a maze.
*
* Called by reflection based on the definition of the user-defined
* function in the schema.
*
* @param width Width of maze
* @param height Height of maze
* @param seed Random number seed, or -1 to create an unseeded random
* @return Table that prints the maze in text form
*/
@SuppressWarnings("unused") // called via reflection
public static ScannableTable generate(int width, int height, int seed) {
return new MazeTable(width, height, seed, false);
}
/** Table function that generates a maze with a solution.
*
*
Called by reflection based on the definition of the user-defined
* function in the schema.
*
* @param width Width of maze
* @param height Height of maze
* @param seed Random number seed, or -1 to create an unseeded random
* @return Table that prints the maze in text form, with solution shown
*/
@SuppressWarnings("unused") // called via reflection
public static ScannableTable solve(int width, int height, int seed) {
return new MazeTable(width, height, seed, true);
}
public RelDataType getRowType(RelDataTypeFactory typeFactory) {
return typeFactory.builder()
.add("S", SqlTypeName.VARCHAR, width * 3 + 1)
.build();
}
public Enumerable scan(DataContext root) {
final Random random = seed >= 0 ? new Random(seed) : new Random();
final Maze maze = new Maze(width, height);
final PrintWriter pw = Util.printWriter(System.out);
maze.layout(random, pw);
if (Maze.DEBUG) {
maze.print(pw, true);
}
return new AbstractEnumerable() {
public Enumerator enumerator() {
final Set solutionSet;
if (solution) {
solutionSet = maze.solve(0, 0);
} else {
solutionSet = null;
}
return Linq4j.transform(maze.enumerator(solutionSet),
s -> new Object[] {s});
}
};
}
}
// End MazeTable.java