Merge pull request #20 from GingerYouth/mos-1022

First version of identical nodes finding implementation with some tests.

src/main/java/org/cqfn/astranaut/core/algorithms/Identical.java

@@ -0,0 +1,97 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 Ivan Kniazkov
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cqfn.astranaut.core.algorithms;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.cqfn.astranaut.core.Node;
+import org.cqfn.astranaut.core.algorithms.hash.SimpleHash;
+
+/**
+ * A class which finds and returns identical nodes in a tree.
+ * The nodes are identical if their data is not empty, and their {@link SimpleHash} equals.
+ *
+ * @since 1.1.5
+ */
+@SuppressWarnings("PMD.ConstructorShouldDoInitialization")
+public class Identical {
+ /**
+ * The root of the tree to search in.
+ */
+ private final Node root;
+
+ /**
+ * The {@link SimpleHash} storage for the tree nodes.
+ */
+ private final SimpleHash hashes;
+
+ /**
+ * The map of the calculated hashes and corresponding nodes.
+ */
+ private final Map<Integer, Set<Node>> results = new HashMap<>();
+
+ /**
+ * Constructor.
+ *
+ * @param root The root of the tree to search in
+ */
+ public Identical(final Node root) {
+ this.root = root;
+ this.hashes = new SimpleHash();
+ }
+
+ /**
+ * Get identical nodes.
+ *
+ * @return The set of sets with identical nodes.
+ */
+ public Set<Set<Node>> get() {
+ this.search(this.root);
+ return this.results.values()
+ .stream()
+ .filter(set -> set.size() >= 2)
+ .collect(Collectors.toSet());
+ }
+
+ /**
+ * Calculates {@link SimpleHash} recursively for all nodes with non-empty data and
+ * adds entries to the resulting map.
+ *
+ * @param node The current node to process
+ */
+ private void search(final Node node) {
+ if (!node.getData().isEmpty()) {
+ this.results.computeIfAbsent(
+ this.hashes.calculate(node),
+ s -> new HashSet<>()
+ ).add(node);
+ }
+ for (final Node child: node.getChildrenList()) {
+ this.search(child);
+ }
+ }
+}

src/main/java/org/cqfn/astranaut/core/algorithms/hash/SimpleHash.java

@@ -0,0 +1,61 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 Ivan Kniazkov
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cqfn.astranaut.core.algorithms.hash;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.cqfn.astranaut.core.Node;
+
+/**
+ * Computes the simple hash of a node, that is, a hash that is computed from the type
+ * and the data of the node itself, regardless of the children of the node.
+ *
+ * @since 1.1.5
+ */
+public final class SimpleHash implements Hash {
+ /**
+ * A table with the calculated hashes.
+ * Since nodes are immutable, a hash calculated once for a node will never change.
+ */
+ private final Map<Node, Integer> calculated;
+
+ /**
+ * Constructor.
+ */
+ public SimpleHash() {
+ this.calculated = new HashMap<>();
+ }
+
+ @Override
+ public int calculate(final Node node) {
+ final int hash;
+ if (this.calculated.containsKey(node)) {
+ hash = this.calculated.get(node);
+ } else {
+ hash = node.getTypeName().hashCode() * 31 + node.getData().hashCode();
+ this.calculated.put(node, hash);
+ }
+ return hash;
+ }
+}

src/test/java/org/cqfn/astranaut/core/algorithms/IdenticalTest.java

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+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 Ivan Kniazkov
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cqfn.astranaut.core.algorithms;
+
+import java.util.Set;
+import org.cqfn.astranaut.core.DraftNode;
+import org.cqfn.astranaut.core.Node;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link Identical} class.
+ *
+ * @since 1.1.5
+ */
+class IdenticalTest {
+ @Test
+ void testIdenticalSets() {
+ final Node original = DraftNode.createByDescription(
+ "T<\"a\">(T<\"b\">,T<\"c\">(F<\"a\">,T<\"b\">,T<\"a\">,F<\"a\">))"
+ );
+ final Identical identical = new Identical(original);
+ final Set<Set<Node>> identicals = identical.get();
+ Assertions.assertEquals(3, identicals.size());
+ }
+
+ @Test
+ void testNoIdenticals() {
+ final Node original = DraftNode.createByDescription(
+ "T<\"a\">(T<\"b\">,T<\"c\">(F<\"a\">,F<\"b\">,F<\"c\">,K<\"a\">))"
+ );
+ final Identical identical = new Identical(original);
+ final Set<Set<Node>> identicals = identical.get();
+ Assertions.assertEquals(0, identicals.size());
+ }
+
+ @Test
+ void testIdenticalsAndEmptyData() {
+ final Node original = DraftNode.createByDescription(
+ "T<\"a\">(T<\"b\">,T<\"c\">(F<\"a\">,T<\"b\">,T<\"a\">,F,F,T))"
+ );
+ final Identical identical = new Identical(original);
+ final Set<Set<Node>> identicals = identical.get();
+ Assertions.assertEquals(2, identicals.size());
+ }
+}