diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..097f9f9 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,9 @@ +# +# https://help.github.com/articles/dealing-with-line-endings/ +# +# Linux start script should use lf +/gradlew text eol=lf + +# These are Windows script files and should use crlf +*.bat text eol=crlf + diff --git a/.gitignore b/.gitignore index bd26a88..f4f772d 100644 --- a/.gitignore +++ b/.gitignore @@ -1,3 +1,8 @@ *.idea out/** -*.iml \ No newline at end of file +*.iml +# Ignore Gradle project-specific cache directory +.gradle + +# Ignore Gradle build output directory +build diff --git a/README.md b/README.md index 210fafd..e6e5f56 100644 --- a/README.md +++ b/README.md @@ -1,9 +1,50 @@ # A-Star-Java-Implementation -A* also called A Star, algorithm java implementation -This is a java implementation of the A Star algorithm. I couldn't find any good java implementations of this famous AI algorithm on the web so I decided to make my own. +A*, also called A Star, is a graph traversal and path search algorithm, which is used in many fields of computer science due to its completeness, optimality, and optimal efficiency. -The implementation includes 3 files: - - AStar.java : Main algorithm class. - - Node.java : Class for the nodes used by the algorithm. - - AStarTest.java : Class with a main method and a simple test for the algorithm implementation +The implementation includes several files: + - AStar.java: Main algorithm class. + - Node.java: Class for the nodes used by the algorithm. + - searchstrategy package: Strategy pattern with several map search algorithms: + 1. Diagonals - when enabled, also considers diagonal moves + 2. Manhattan distance - default mode, only considers vertical and horizontal moves + + +## A* specifications + +- For node n, gScore[n] is the cost of the cheapest path currently known from start to n. +- For node n, fScore[n] = gScore[n] + heuristic(n), where gScore(n) is the distance from the starting node to n + and h(n) is a heuristic value of estimation distance from node n to finish node. +- h(n) is a heuristic value of estimation distance from node n to finish node + +## Example provided + +### Search Area + + 0 1 2 3 4 5 6 + 0 - - - - - - - + 1 - - - B - - - + 2 - I - B - F - + 3 - - - B - - - + 4 - - - - - - - + 5 - - - - - - - + +### Search Path with diagonals + + 0 1 2 3 4 5 6 + 0 - - - * - - - + 1 - - * B * - - + 2 - I* - B - *F - + 3 - - - B - - - + 4 - - - - - - - + 5 - - - - - - - + +### Search Path without diagonals + + 0 1 2 3 4 5 6 + 0 - - * * * - - + 1 - - * B * - - + 2 - I* * B * *F - + 3 - - - B - - - + 4 - - - - - - - + 5 - - - - - - - diff --git a/app/build.gradle.kts b/app/build.gradle.kts new file mode 100644 index 0000000..7f15958 --- /dev/null +++ b/app/build.gradle.kts @@ -0,0 +1,37 @@ +/* + * This file was generated by the Gradle 'init' task. + * + * This generated file contains a sample Java application project to get you started. + * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle + * User Manual available at https://docs.gradle.org/7.6/userguide/building_java_projects.html + */ + +plugins { + // Apply the application plugin to add support for building a CLI application in Java. + application +} + +repositories { + // Use Maven Central for resolving dependencies. + mavenCentral() +} + +dependencies { + // Use JUnit Jupiter for testing. + testImplementation("org.junit.jupiter:junit-jupiter:5.9.1") + + // This dependency is used by the application. + implementation("com.google.guava:guava:31.1-jre") + + testImplementation("org.hamcrest:hamcrest:2.2") +} + +application { + // Define the main class for the application. + mainClass.set("com.ai.astar.App") +} + +tasks.named("test") { + // Use JUnit Platform for unit tests. + useJUnitPlatform() +} diff --git a/app/src/main/java/com/ai/astar/domain/AStar.java b/app/src/main/java/com/ai/astar/domain/AStar.java new file mode 100644 index 0000000..4e06df8 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/AStar.java @@ -0,0 +1,126 @@ +package com.ai.astar.domain; + +import com.ai.astar.domain.searchstrategy.DiagonalMapChecker; +import com.ai.astar.domain.searchstrategy.ManhattanMapChecker; +import com.ai.astar.domain.searchstrategy.MapChecker; +import com.ai.astar.domain.searchstrategy.NoOpChecker; + +import java.util.*; + +public class AStar { + private static final int DEFAULT_MANHATTAN_COST = 10; + private static final int DEFAULT_DIAGONAL_COST = 14; + private final Node[][] searchArea; + private final PriorityQueue openList; + private final Set closedSet; + private final Node initialNode; + private final Node finalNode; + private final MapChecker diagonalsChecker; + private final MapChecker manhattanChecker; + + public AStar( + int rows, + int cols, + Node initialNode, + Node finalNode, + int[][] blocksArray, + boolean searchDiagonals, + int diagonalCost, + int hvCost) { + this.initialNode = initialNode; + this.finalNode = finalNode; + this.searchArea = new Node[rows][cols]; + this.openList = new PriorityQueue<>(Comparator.comparingInt(Node::fScore)); + initNodes(); + initBlocks(blocksArray); + this.closedSet = new HashSet<>(); + if (searchDiagonals) { + this.diagonalsChecker = new DiagonalMapChecker(searchArea, openList, closedSet, diagonalCost); + } else { + this.diagonalsChecker = new NoOpChecker(null, null, null); + } + this.manhattanChecker = new ManhattanMapChecker(searchArea, openList, closedSet, hvCost); + } + + public AStar(int rows, int cols, Node initialNode, Node finalNode, int[][] blocksArray, boolean searchDiagonals) { + this(rows, cols, initialNode, finalNode, blocksArray, searchDiagonals, DEFAULT_DIAGONAL_COST, DEFAULT_MANHATTAN_COST); + } + + private void initNodes() { + for (int i = 0; i < searchArea.length; i++) { + for (int j = 0; j < searchArea[0].length; j++) { + Node node = Node.of(i, j); + node.calculateHeuristic(finalNode); + this.searchArea[i][j] = node; + } + } + } + + private void initBlocks(int[][] blocksArray) { + for (int[] block : blocksArray) { + int row = block[0]; + int col = block[1]; + if (row < 0 || row >= searchArea.length) { + continue; + } + if (col < 0 || col >= searchArea[0].length) { + continue; + } + this.searchArea[row][col].setAsBlocked(); + } + } + + public List findPath() { + openList.add(initialNode); + while (!openList.isEmpty()) { + Node currentNode = openList.poll(); + closedSet.add(currentNode); + if (isFinalNode(currentNode)) { + return bestPath(currentNode); + } else { + addAdjacentNodes(currentNode); + } + } + return new ArrayList<>(); + } + + private List bestPath(Node currentNode) { + List path = new ArrayList<>(); + path.add(currentNode); + Node parent; + while ((parent = currentNode.parent()) != null) { + path.add(0, parent); + currentNode = parent; + } + return path; + } + + private void addAdjacentNodes(Node currentNode) { + int row = currentNode.row(); + int col = currentNode.col(); + addAdjacentUpperRow(currentNode, row, col); + addAdjacentMiddleRow(currentNode, row, col); + addAdjacentLowerRow(currentNode, row, col); + } + + private void addAdjacentLowerRow(Node currentNode, int row, int col) { + diagonalsChecker.checkNode(currentNode, col, row + 1); + manhattanChecker.checkNode(currentNode, col, row + 1); + } + + private void addAdjacentMiddleRow(Node currentNode, int row, int col) { + manhattanChecker.checkNode(currentNode, col - 1, row); + manhattanChecker.checkNode(currentNode, col + 1, row); + } + + private void addAdjacentUpperRow(Node currentNode, int row, int col) { + diagonalsChecker.checkNode(currentNode, col, row - 1); + manhattanChecker.checkNode(currentNode, col, row - 1); + } + + private boolean isFinalNode(Node currentNode) { + return currentNode.equals(finalNode); + } + +} + diff --git a/app/src/main/java/com/ai/astar/domain/Node.java b/app/src/main/java/com/ai/astar/domain/Node.java new file mode 100644 index 0000000..1942901 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/Node.java @@ -0,0 +1,99 @@ +package com.ai.astar.domain; + +public class Node { + + private int gScore; + private int fScore; + private int h; + private final int row; + private final int col; + private boolean isBlocked; + private Node parent; + + private Node(int row, int col) { + super(); + this.row = row; + this.col = col; + } + + public static Node of(int row, int col) { + return new Node(row, col); + } + + public void calculateHeuristic(Node finalNode) { + this.h = Math.abs(finalNode.row() - row) + Math.abs(finalNode.col() - col); + } + + public void updateNode(Node currentNode, int cost) { + this.parent = currentNode; + updateGScore(currentNode.gScore(), cost); + updateFScore(); + } + + public boolean checkBetterPath(Node currentNode, int cost) { + int updatedScore = currentNode.gScore() + cost; + if (updatedScore < gScore()) { + updateNode(currentNode, cost); + return true; + } + return false; + } + + public int gScore() { + return gScore; + } + + private void updateGScore(int currentGScore, int cost) { + this.gScore = currentGScore + cost; + } + + public int fScore() { + return fScore; + } + + private void updateFScore() { + this.fScore = gScore + h; + } + + public Node parent() { + return parent; + } + + public boolean isBlocked() { + return isBlocked; + } + + public void setAsBlocked() { + this.isBlocked = true; + } + + public int row() { + return row; + } + + public int col() { + return col; + } + + @Override + public int hashCode() { + int result = row; + result = 31 * result + col; + return result; + } + + @Override + public boolean equals(Object arg0) { + if (arg0 == null) { + return false; + } + Node other = (Node) arg0; + return this.row() == other.row() && this.col() == other.col(); + } + + @Override + public String toString() { + return "Node [row=" + row + ", col=" + col + "]"; + } + +} diff --git a/app/src/main/java/com/ai/astar/domain/searchstrategy/DiagonalMapChecker.java b/app/src/main/java/com/ai/astar/domain/searchstrategy/DiagonalMapChecker.java new file mode 100644 index 0000000..4533a30 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/searchstrategy/DiagonalMapChecker.java @@ -0,0 +1,22 @@ +package com.ai.astar.domain.searchstrategy; + +import com.ai.astar.domain.Node; + +import java.util.PriorityQueue; +import java.util.Set; + +public class DiagonalMapChecker extends MapChecker { + + private final int diagonalCost; + + public DiagonalMapChecker(Node[][] searchArea, PriorityQueue openList, Set closedSet, int diagonalCost) { + super(searchArea, openList, closedSet); + this.diagonalCost = diagonalCost; + } + + @Override + public void checkNode(Node currentNode, int col, int row) { + check(currentNode, col - 1, row, diagonalCost); + check(currentNode, col + 1, row, diagonalCost); + } +} diff --git a/app/src/main/java/com/ai/astar/domain/searchstrategy/ManhattanMapChecker.java b/app/src/main/java/com/ai/astar/domain/searchstrategy/ManhattanMapChecker.java new file mode 100644 index 0000000..0d55ce8 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/searchstrategy/ManhattanMapChecker.java @@ -0,0 +1,21 @@ +package com.ai.astar.domain.searchstrategy; + +import com.ai.astar.domain.Node; + +import java.util.PriorityQueue; +import java.util.Set; + +public class ManhattanMapChecker extends MapChecker { + + private final int manhattanCost; + + public ManhattanMapChecker(Node[][] searchArea, PriorityQueue openList, Set closedSet, int manhattanCost) { + super(searchArea, openList, closedSet); + this.manhattanCost = manhattanCost; + } + + @Override + public void checkNode(Node currentNode, int col, int row) { + check(currentNode, col, row, manhattanCost); + } +} diff --git a/app/src/main/java/com/ai/astar/domain/searchstrategy/MapCheck.java b/app/src/main/java/com/ai/astar/domain/searchstrategy/MapCheck.java new file mode 100644 index 0000000..0219c9d --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/searchstrategy/MapCheck.java @@ -0,0 +1,9 @@ +package com.ai.astar.domain.searchstrategy; + +import com.ai.astar.domain.Node; + +public interface MapCheck { + + void checkNode(Node currentNode, int col, int row); + +} diff --git a/app/src/main/java/com/ai/astar/domain/searchstrategy/MapChecker.java b/app/src/main/java/com/ai/astar/domain/searchstrategy/MapChecker.java new file mode 100644 index 0000000..c8b0d35 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/searchstrategy/MapChecker.java @@ -0,0 +1,46 @@ +package com.ai.astar.domain.searchstrategy; + +import com.ai.astar.domain.Node; + +import java.util.PriorityQueue; +import java.util.Set; + +public abstract class MapChecker implements MapCheck { + protected final Node[][] searchArea; + protected final PriorityQueue openList; + protected final Set closedSet; + protected final int columns; + + protected MapChecker(Node[][] searchArea, PriorityQueue openList, Set closedSet) { + this.searchArea = searchArea; + this.openList = openList; + this.closedSet = closedSet; + this.columns = searchArea == null ? 0 : searchArea[0].length; + } + + protected void check(Node currentNode, int col, int row, int cost) { + if (row < 0 || row >= searchArea.length) { + return; + } + if (col < 0 || col >= columns) { + return; + } + Node adjacentNode = searchArea[row][col]; + if (adjacentNode.isBlocked() || closedSet.contains(adjacentNode)) { + return; + } + if (!openList.contains(adjacentNode)) { + adjacentNode.updateNode(currentNode, cost); + openList.add(adjacentNode); + } else { + boolean changed = adjacentNode.checkBetterPath(currentNode, cost); + if (changed) { + // Remove and Add the changed node, so that the PriorityQueue can sort again its + // contents with the modified "finalCost" value of the modified node + openList.remove(adjacentNode); + openList.add(adjacentNode); + } + } + } + +} diff --git a/app/src/main/java/com/ai/astar/domain/searchstrategy/NoOpChecker.java b/app/src/main/java/com/ai/astar/domain/searchstrategy/NoOpChecker.java new file mode 100644 index 0000000..7c0eb32 --- /dev/null +++ b/app/src/main/java/com/ai/astar/domain/searchstrategy/NoOpChecker.java @@ -0,0 +1,18 @@ +package com.ai.astar.domain.searchstrategy; + +import com.ai.astar.domain.Node; + +import java.util.PriorityQueue; +import java.util.Set; + +public class NoOpChecker extends MapChecker { + + public NoOpChecker(Node[][] searchArea, PriorityQueue openList, Set closedSet) { + super(searchArea, openList, closedSet); + } + + @Override + public void checkNode(Node currentNode, int col, int row) { + // nothing to do + } +} diff --git a/app/src/test/java/com/ai/astar/AStarTest.java b/app/src/test/java/com/ai/astar/AStarTest.java new file mode 100644 index 0000000..d311f8b --- /dev/null +++ b/app/src/test/java/com/ai/astar/AStarTest.java @@ -0,0 +1,49 @@ +package com.ai.astar; + +import com.ai.astar.domain.AStar; +import com.ai.astar.domain.Node; +import org.junit.jupiter.api.Test; + +import java.util.ArrayList; +import java.util.List; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +class AStarTest { + + private final Node initialNode = Node.of(2, 1); + private final Node finalNode = Node.of(2, 5); + private final int rows = 6; + private final int cols = 7; + private final int[][] blocksArray = new int[][]{{1, 3}, {2, 3}, {3, 3}}; + + @Test + void shouldFindShortestPath_whenSearchingDiagonals() { + AStar aStar = new AStar(rows, cols, initialNode, finalNode, blocksArray, true); + List expected = new ArrayList<>(); + expected.add(Node.of(2, 1)); + expected.add(Node.of(1, 2)); + expected.add(Node.of(0, 3)); + expected.add(Node.of(1, 4)); + expected.add(Node.of(2, 5)); + List path = aStar.findPath(); + assertEquals(expected, path); + } + + @Test + void shouldFindShortestPath_whenSearchingHorizontalVertical() { + AStar aStar = new AStar(rows, cols, initialNode, finalNode, blocksArray, false); + List expected = new ArrayList<>(); + expected.add(Node.of(2, 1)); + expected.add(Node.of(2, 2)); + expected.add(Node.of(1, 2)); + expected.add(Node.of(0, 2)); + expected.add(Node.of(0, 3)); + expected.add(Node.of(0, 4)); + expected.add(Node.of(1, 4)); + expected.add(Node.of(2, 4)); + expected.add(Node.of(2, 5)); + List path = aStar.findPath(); + assertEquals(expected, path); + } +} diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar new file mode 100644 index 0000000..943f0cb Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties new file mode 100644 index 0000000..f398c33 --- /dev/null +++ b/gradle/wrapper/gradle-wrapper.properties @@ -0,0 +1,6 @@ +distributionBase=GRADLE_USER_HOME +distributionPath=wrapper/dists +distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip +networkTimeout=10000 +zipStoreBase=GRADLE_USER_HOME +zipStorePath=wrapper/dists diff --git a/gradlew b/gradlew new file mode 100755 index 0000000..65dcd68 --- /dev/null +++ b/gradlew @@ -0,0 +1,244 @@ +#!/bin/sh + +# +# Copyright © 2015-2021 the original 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 +# +# https://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. +# + +############################################################################## +# +# Gradle start up script for POSIX generated by Gradle. +# +# Important for running: +# +# (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is +# noncompliant, but you have some other compliant shell such as ksh or +# bash, then to run this script, type that shell name before the whole +# command line, like: +# +# ksh Gradle +# +# Busybox and similar reduced shells will NOT work, because this script +# requires all of these POSIX shell features: +# * functions; +# * expansions «$var», «${var}», «${var:-default}», «${var+SET}», +# «${var#prefix}», «${var%suffix}», and «$( cmd )»; +# * compound commands having a testable exit status, especially «case»; +# * various built-in commands including «command», «set», and «ulimit». +# +# Important for patching: +# +# (2) This script targets any POSIX shell, so it avoids extensions provided +# by Bash, Ksh, etc; in particular arrays are avoided. +# +# The "traditional" practice of packing multiple parameters into a +# space-separated string is a well documented source of bugs and security +# problems, so this is (mostly) avoided, by progressively accumulating +# options in "$@", and eventually passing that to Java. +# +# Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS, +# and GRADLE_OPTS) rely on word-splitting, this is performed explicitly; +# see the in-line comments for details. +# +# There are tweaks for specific operating systems such as AIX, CygWin, +# Darwin, MinGW, and NonStop. +# +# (3) This script is generated from the Groovy template +# https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt +# within the Gradle project. +# +# You can find Gradle at https://github.com/gradle/gradle/. +# +############################################################################## + +# Attempt to set APP_HOME + +# Resolve links: $0 may be a link +app_path=$0 + +# Need this for daisy-chained symlinks. +while + APP_HOME=${app_path%"${app_path##*/}"} # leaves a trailing /; empty if no leading path + [ -h "$app_path" ] +do + ls=$( ls -ld "$app_path" ) + link=${ls#*' -> '} + case $link in #( + /*) app_path=$link ;; #( + *) app_path=$APP_HOME$link ;; + esac +done + +# This is normally unused +# shellcheck disable=SC2034 +APP_BASE_NAME=${0##*/} +APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit + +# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. +DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"' + +# Use the maximum available, or set MAX_FD != -1 to use that value. +MAX_FD=maximum + +warn () { + echo "$*" +} >&2 + +die () { + echo + echo "$*" + echo + exit 1 +} >&2 + +# OS specific support (must be 'true' or 'false'). +cygwin=false +msys=false +darwin=false +nonstop=false +case "$( uname )" in #( + CYGWIN* ) cygwin=true ;; #( + Darwin* ) darwin=true ;; #( + MSYS* | MINGW* ) msys=true ;; #( + NONSTOP* ) nonstop=true ;; +esac + +CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar + + +# Determine the Java command to use to start the JVM. +if [ -n "$JAVA_HOME" ] ; then + if [ -x "$JAVA_HOME/jre/sh/java" ] ; then + # IBM's JDK on AIX uses strange locations for the executables + JAVACMD=$JAVA_HOME/jre/sh/java + else + JAVACMD=$JAVA_HOME/bin/java + fi + if [ ! -x "$JAVACMD" ] ; then + die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME + +Please set the JAVA_HOME variable in your environment to match the +location of your Java installation." + fi +else + JAVACMD=java + which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. + +Please set the JAVA_HOME variable in your environment to match the +location of your Java installation." +fi + +# Increase the maximum file descriptors if we can. +if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then + case $MAX_FD in #( + max*) + # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked. + # shellcheck disable=SC3045 + MAX_FD=$( ulimit -H -n ) || + warn "Could not query maximum file descriptor limit" + esac + case $MAX_FD in #( + '' | soft) :;; #( + *) + # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked. + # shellcheck disable=SC3045 + ulimit -n "$MAX_FD" || + warn "Could not set maximum file descriptor limit to $MAX_FD" + esac +fi + +# Collect all arguments for the java command, stacking in reverse order: +# * args from the command line +# * the main class name +# * -classpath +# * -D...appname settings +# * --module-path (only if needed) +# * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables. + +# For Cygwin or MSYS, switch paths to Windows format before running java +if "$cygwin" || "$msys" ; then + APP_HOME=$( cygpath --path --mixed "$APP_HOME" ) + CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" ) + + JAVACMD=$( cygpath --unix "$JAVACMD" ) + + # Now convert the arguments - kludge to limit ourselves to /bin/sh + for arg do + if + case $arg in #( + -*) false ;; # don't mess with options #( + /?*) t=${arg#/} t=/${t%%/*} # looks like a POSIX filepath + [ -e "$t" ] ;; #( + *) false ;; + esac + then + arg=$( cygpath --path --ignore --mixed "$arg" ) + fi + # Roll the args list around exactly as many times as the number of + # args, so each arg winds up back in the position where it started, but + # possibly modified. + # + # NB: a `for` loop captures its iteration list before it begins, so + # changing the positional parameters here affects neither the number of + # iterations, nor the values presented in `arg`. + shift # remove old arg + set -- "$@" "$arg" # push replacement arg + done +fi + +# Collect all arguments for the java command; +# * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of +# shell script including quotes and variable substitutions, so put them in +# double quotes to make sure that they get re-expanded; and +# * put everything else in single quotes, so that it's not re-expanded. + +set -- \ + "-Dorg.gradle.appname=$APP_BASE_NAME" \ + -classpath "$CLASSPATH" \ + org.gradle.wrapper.GradleWrapperMain \ + "$@" + +# Stop when "xargs" is not available. +if ! command -v xargs >/dev/null 2>&1 +then + die "xargs is not available" +fi + +# Use "xargs" to parse quoted args. +# +# With -n1 it outputs one arg per line, with the quotes and backslashes removed. +# +# In Bash we could simply go: +# +# readarray ARGS < <( xargs -n1 <<<"$var" ) && +# set -- "${ARGS[@]}" "$@" +# +# but POSIX shell has neither arrays nor command substitution, so instead we +# post-process each arg (as a line of input to sed) to backslash-escape any +# character that might be a shell metacharacter, then use eval to reverse +# that process (while maintaining the separation between arguments), and wrap +# the whole thing up as a single "set" statement. +# +# This will of course break if any of these variables contains a newline or +# an unmatched quote. +# + +eval "set -- $( + printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" | + xargs -n1 | + sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' | + tr '\n' ' ' + )" '"$@"' + +exec "$JAVACMD" "$@" diff --git a/gradlew.bat b/gradlew.bat new file mode 100644 index 0000000..93e3f59 --- /dev/null +++ b/gradlew.bat @@ -0,0 +1,92 @@ +@rem +@rem Copyright 2015 the original author or authors. +@rem +@rem Licensed under the Apache License, Version 2.0 (the "License"); +@rem you may not use this file except in compliance with the License. +@rem You may obtain a copy of the License at +@rem +@rem https://www.apache.org/licenses/LICENSE-2.0 +@rem +@rem Unless required by applicable law or agreed to in writing, software +@rem distributed under the License is distributed on an "AS IS" BASIS, +@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +@rem See the License for the specific language governing permissions and +@rem limitations under the License. +@rem + +@if "%DEBUG%"=="" @echo off +@rem ########################################################################## +@rem +@rem Gradle startup script for Windows +@rem +@rem ########################################################################## + +@rem Set local scope for the variables with windows NT shell +if "%OS%"=="Windows_NT" setlocal + +set DIRNAME=%~dp0 +if "%DIRNAME%"=="" set DIRNAME=. +@rem This is normally unused +set APP_BASE_NAME=%~n0 +set APP_HOME=%DIRNAME% + +@rem Resolve any "." and ".." in APP_HOME to make it shorter. +for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi + +@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. +set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m" + +@rem Find java.exe +if defined JAVA_HOME goto findJavaFromJavaHome + +set JAVA_EXE=java.exe +%JAVA_EXE% -version >NUL 2>&1 +if %ERRORLEVEL% equ 0 goto execute + +echo. +echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. +echo. +echo Please set the JAVA_HOME variable in your environment to match the +echo location of your Java installation. + +goto fail + +:findJavaFromJavaHome +set JAVA_HOME=%JAVA_HOME:"=% +set JAVA_EXE=%JAVA_HOME%/bin/java.exe + +if exist "%JAVA_EXE%" goto execute + +echo. +echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% +echo. +echo Please set the JAVA_HOME variable in your environment to match the +echo location of your Java installation. + +goto fail + +:execute +@rem Setup the command line + +set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar + + +@rem Execute Gradle +"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %* + +:end +@rem End local scope for the variables with windows NT shell +if %ERRORLEVEL% equ 0 goto mainEnd + +:fail +rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of +rem the _cmd.exe /c_ return code! +set EXIT_CODE=%ERRORLEVEL% +if %EXIT_CODE% equ 0 set EXIT_CODE=1 +if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE% +exit /b %EXIT_CODE% + +:mainEnd +if "%OS%"=="Windows_NT" endlocal + +:omega diff --git a/settings.gradle.kts b/settings.gradle.kts new file mode 100644 index 0000000..566c9d9 --- /dev/null +++ b/settings.gradle.kts @@ -0,0 +1,11 @@ +/* + * This file was generated by the Gradle 'init' task. + * + * The settings file is used to specify which projects to include in your build. + * + * Detailed information about configuring a multi-project build in Gradle can be found + * in the user manual at https://docs.gradle.org/7.6/userguide/multi_project_builds.html + */ + +rootProject.name = "A-Star-Java-Implementation" +include("app") diff --git a/src/com/ai/astar/AStar.java b/src/com/ai/astar/AStar.java deleted file mode 100644 index ee17f27..0000000 --- a/src/com/ai/astar/AStar.java +++ /dev/null @@ -1,219 +0,0 @@ -package com.ai.astar; - -import java.util.*; - -/** - * A Star Algorithm - * - * @author Marcelo Surriabre - * @version 2.1, 2017-02-23 - */ -public class AStar { - private static int DEFAULT_HV_COST = 10; // Horizontal - Vertical Cost - private static int DEFAULT_DIAGONAL_COST = 14; - private int hvCost; - private int diagonalCost; - private Node[][] searchArea; - private PriorityQueue openList; - private Set closedSet; - private Node initialNode; - private Node finalNode; - - public AStar(int rows, int cols, Node initialNode, Node finalNode, int hvCost, int diagonalCost) { - this.hvCost = hvCost; - this.diagonalCost = diagonalCost; - setInitialNode(initialNode); - setFinalNode(finalNode); - this.searchArea = new Node[rows][cols]; - this.openList = new PriorityQueue(new Comparator() { - @Override - public int compare(Node node0, Node node1) { - return Integer.compare(node0.getF(), node1.getF()); - } - }); - setNodes(); - this.closedSet = new HashSet<>(); - } - - public AStar(int rows, int cols, Node initialNode, Node finalNode) { - this(rows, cols, initialNode, finalNode, DEFAULT_HV_COST, DEFAULT_DIAGONAL_COST); - } - - private void setNodes() { - for (int i = 0; i < searchArea.length; i++) { - for (int j = 0; j < searchArea[0].length; j++) { - Node node = new Node(i, j); - node.calculateHeuristic(getFinalNode()); - this.searchArea[i][j] = node; - } - } - } - - public void setBlocks(int[][] blocksArray) { - for (int i = 0; i < blocksArray.length; i++) { - int row = blocksArray[i][0]; - int col = blocksArray[i][1]; - setBlock(row, col); - } - } - - public List findPath() { - openList.add(initialNode); - while (!isEmpty(openList)) { - Node currentNode = openList.poll(); - closedSet.add(currentNode); - if (isFinalNode(currentNode)) { - return getPath(currentNode); - } else { - addAdjacentNodes(currentNode); - } - } - return new ArrayList(); - } - - private List getPath(Node currentNode) { - List path = new ArrayList(); - path.add(currentNode); - Node parent; - while ((parent = currentNode.getParent()) != null) { - path.add(0, parent); - currentNode = parent; - } - return path; - } - - private void addAdjacentNodes(Node currentNode) { - addAdjacentUpperRow(currentNode); - addAdjacentMiddleRow(currentNode); - addAdjacentLowerRow(currentNode); - } - - private void addAdjacentLowerRow(Node currentNode) { - int row = currentNode.getRow(); - int col = currentNode.getCol(); - int lowerRow = row + 1; - if (lowerRow < getSearchArea().length) { - if (col - 1 >= 0) { - checkNode(currentNode, col - 1, lowerRow, getDiagonalCost()); // Comment this line if diagonal movements are not allowed - } - if (col + 1 < getSearchArea()[0].length) { - checkNode(currentNode, col + 1, lowerRow, getDiagonalCost()); // Comment this line if diagonal movements are not allowed - } - checkNode(currentNode, col, lowerRow, getHvCost()); - } - } - - private void addAdjacentMiddleRow(Node currentNode) { - int row = currentNode.getRow(); - int col = currentNode.getCol(); - int middleRow = row; - if (col - 1 >= 0) { - checkNode(currentNode, col - 1, middleRow, getHvCost()); - } - if (col + 1 < getSearchArea()[0].length) { - checkNode(currentNode, col + 1, middleRow, getHvCost()); - } - } - - private void addAdjacentUpperRow(Node currentNode) { - int row = currentNode.getRow(); - int col = currentNode.getCol(); - int upperRow = row - 1; - if (upperRow >= 0) { - if (col - 1 >= 0) { - checkNode(currentNode, col - 1, upperRow, getDiagonalCost()); // Comment this if diagonal movements are not allowed - } - if (col + 1 < getSearchArea()[0].length) { - checkNode(currentNode, col + 1, upperRow, getDiagonalCost()); // Comment this if diagonal movements are not allowed - } - checkNode(currentNode, col, upperRow, getHvCost()); - } - } - - private void checkNode(Node currentNode, int col, int row, int cost) { - Node adjacentNode = getSearchArea()[row][col]; - if (!adjacentNode.isBlock() && !getClosedSet().contains(adjacentNode)) { - if (!getOpenList().contains(adjacentNode)) { - adjacentNode.setNodeData(currentNode, cost); - getOpenList().add(adjacentNode); - } else { - boolean changed = adjacentNode.checkBetterPath(currentNode, cost); - if (changed) { - // Remove and Add the changed node, so that the PriorityQueue can sort again its - // contents with the modified "finalCost" value of the modified node - getOpenList().remove(adjacentNode); - getOpenList().add(adjacentNode); - } - } - } - } - - private boolean isFinalNode(Node currentNode) { - return currentNode.equals(finalNode); - } - - private boolean isEmpty(PriorityQueue openList) { - return openList.size() == 0; - } - - private void setBlock(int row, int col) { - this.searchArea[row][col].setBlock(true); - } - - public Node getInitialNode() { - return initialNode; - } - - public void setInitialNode(Node initialNode) { - this.initialNode = initialNode; - } - - public Node getFinalNode() { - return finalNode; - } - - public void setFinalNode(Node finalNode) { - this.finalNode = finalNode; - } - - public Node[][] getSearchArea() { - return searchArea; - } - - public void setSearchArea(Node[][] searchArea) { - this.searchArea = searchArea; - } - - public PriorityQueue getOpenList() { - return openList; - } - - public void setOpenList(PriorityQueue openList) { - this.openList = openList; - } - - public Set getClosedSet() { - return closedSet; - } - - public void setClosedSet(Set closedSet) { - this.closedSet = closedSet; - } - - public int getHvCost() { - return hvCost; - } - - public void setHvCost(int hvCost) { - this.hvCost = hvCost; - } - - private int getDiagonalCost() { - return diagonalCost; - } - - private void setDiagonalCost(int diagonalCost) { - this.diagonalCost = diagonalCost; - } -} - diff --git a/src/com/ai/astar/AStarTest.java b/src/com/ai/astar/AStarTest.java deleted file mode 100644 index 65264c4..0000000 --- a/src/com/ai/astar/AStarTest.java +++ /dev/null @@ -1,65 +0,0 @@ -package com.ai.astar; - -import java.util.List; - -public class AStarTest { - - public static void main(String[] args) { - Node initialNode = new Node(2, 1); - Node finalNode = new Node(2, 5); - int rows = 6; - int cols = 7; - AStar aStar = new AStar(rows, cols, initialNode, finalNode); - int[][] blocksArray = new int[][]{{1, 3}, {2, 3}, {3, 3}}; - aStar.setBlocks(blocksArray); - List path = aStar.findPath(); - for (Node node : path) { - System.out.println(node); - } - - //Search Area - // 0 1 2 3 4 5 6 - // 0 - - - - - - - - // 1 - - - B - - - - // 2 - I - B - F - - // 3 - - - B - - - - // 4 - - - - - - - - // 5 - - - - - - - - - //Expected output with diagonals - //Node [row=2, col=1] - //Node [row=1, col=2] - //Node [row=0, col=3] - //Node [row=1, col=4] - //Node [row=2, col=5] - - //Search Path with diagonals - // 0 1 2 3 4 5 6 - // 0 - - - * - - - - // 1 - - * B * - - - // 2 - I* - B - *F - - // 3 - - - B - - - - // 4 - - - - - - - - // 5 - - - - - - - - - //Expected output without diagonals - //Node [row=2, col=1] - //Node [row=2, col=2] - //Node [row=1, col=2] - //Node [row=0, col=2] - //Node [row=0, col=3] - //Node [row=0, col=4] - //Node [row=1, col=4] - //Node [row=2, col=4] - //Node [row=2, col=5] - - //Search Path without diagonals - // 0 1 2 3 4 5 6 - // 0 - - * * * - - - // 1 - - * B * - - - // 2 - I* * B * *F - - // 3 - - - B - - - - // 4 - - - - - - - - // 5 - - - - - - - - } -} diff --git a/src/com/ai/astar/Node.java b/src/com/ai/astar/Node.java deleted file mode 100644 index a57f0ca..0000000 --- a/src/com/ai/astar/Node.java +++ /dev/null @@ -1,116 +0,0 @@ -package com.ai.astar; - -/** - * Node Class - * - * @author Marcelo Surriabre - * @version 2.0, 2018-02-23 - */ -public class Node { - - private int g; - private int f; - private int h; - private int row; - private int col; - private boolean isBlock; - private Node parent; - - public Node(int row, int col) { - super(); - this.row = row; - this.col = col; - } - - public void calculateHeuristic(Node finalNode) { - this.h = Math.abs(finalNode.getRow() - getRow()) + Math.abs(finalNode.getCol() - getCol()); - } - - public void setNodeData(Node currentNode, int cost) { - int gCost = currentNode.getG() + cost; - setParent(currentNode); - setG(gCost); - calculateFinalCost(); - } - - public boolean checkBetterPath(Node currentNode, int cost) { - int gCost = currentNode.getG() + cost; - if (gCost < getG()) { - setNodeData(currentNode, cost); - return true; - } - return false; - } - - private void calculateFinalCost() { - int finalCost = getG() + getH(); - setF(finalCost); - } - - @Override - public boolean equals(Object arg0) { - Node other = (Node) arg0; - return this.getRow() == other.getRow() && this.getCol() == other.getCol(); - } - - @Override - public String toString() { - return "Node [row=" + row + ", col=" + col + "]"; - } - - public int getH() { - return h; - } - - public void setH(int h) { - this.h = h; - } - - public int getG() { - return g; - } - - public void setG(int g) { - this.g = g; - } - - public int getF() { - return f; - } - - public void setF(int f) { - this.f = f; - } - - public Node getParent() { - return parent; - } - - public void setParent(Node parent) { - this.parent = parent; - } - - public boolean isBlock() { - return isBlock; - } - - public void setBlock(boolean isBlock) { - this.isBlock = isBlock; - } - - public int getRow() { - return row; - } - - public void setRow(int row) { - this.row = row; - } - - public int getCol() { - return col; - } - - public void setCol(int col) { - this.col = col; - } -}