[#436] utils to diff components

src/main/java/de/bonndan/nivio/model/ComponentDiff.java

@@ -0,0 +1,61 @@
+package de.bonndan.nivio.model;
+
+import org.apache.commons.collections.CollectionUtils;
+import org.springframework.util.StringUtils;
+
+import java.util.*;
+
+public class ComponentDiff {
+
+    /**
+     * Compares changes in two strings.
+     *
+     * @param a       first
+     * @param b       second
+     * @param key     label
+     * @param changes array of changes
+     */
+    public static void compareStrings(String a, String b, String key, List<String> changes) {
+        if (!org.apache.commons.lang3.StringUtils.equals(a, b)) {
+            changes.add(key + " changed to: " + b);
+        }
+    }
+
+    /**
+     * Compares changes in string representation of two objects
+     *
+     * @param a       first
+     * @param b       second
+     * @param key     label
+     * @param changes array of changes
+     */
+    @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+    public static void compareOptionals(Optional<Object> a, Optional<Object> b, String key, List<String> changes) {
+        if (a.isEmpty() && b.isEmpty()) {
+            return;
+        }
+        if (a.isPresent() && b.isEmpty() || a.isEmpty() && b.isPresent()) {
+            changes.add(key + " changed to: " + b.orElse(""));
+            return;
+        }
+        if (!org.apache.commons.lang3.StringUtils.equals(a.map(Object::toString).orElse(""), b.map(Object::toString).orElse(""))) {
+            changes.add(key + " changed to: " + b);
+        }
+    }
+
+    /**
+     * Compares to string collections.
+     *
+     * @param one     first
+     * @param two     second
+     * @param key     label
+     * @param changes list of changes
+     */
+    public static void compareCollections(Collection<String> one, Collection<String> two, String key, List<String> changes) {
+        Collection<String> disjunction = CollectionUtils.disjunction(one, two);
+        String changedKeys = String.join(",", disjunction);
+        if (!StringUtils.isEmpty(changedKeys)) {
+            changes.add(String.format("%s have differences : '%s'", key, changedKeys));
+        }
+    }
+}

src/test/java/de/bonndan/nivio/model/ComponentDiffTest.java

@@ -0,0 +1,104 @@
+package de.bonndan.nivio.model;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ComponentDiffTest {
+
+    private List<String> changes;
+
+    @BeforeEach
+    void setup() {
+        changes = new ArrayList<>();
+    }
+
+    @Test
+    void twoNulls() {
+        ComponentDiff.compareStrings(null, null, "foo", changes);
+        assertThat(changes).hasSize(0);
+    }
+
+    @Test
+    void twoNull() {
+        ComponentDiff.compareStrings("a", null, "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void oneNull() {
+        ComponentDiff.compareStrings(null, "b", "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void similarString() {
+        ComponentDiff.compareStrings("b", "b", "foo", changes);
+        assertThat(changes).hasSize(0);
+    }
+
+    @Test
+    void differentString() {
+        ComponentDiff.compareStrings("a", "b", "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void bothEmpty() {
+        ComponentDiff.compareOptionals(Optional.empty(), Optional.empty(), "foo", changes);
+        assertThat(changes).hasSize(0);
+    }
+
+    @Test
+    void oneEmpty() {
+        ComponentDiff.compareOptionals(Optional.empty(), Optional.of("a"), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void twoEmpty() {
+        ComponentDiff.compareOptionals(Optional.of("a"), Optional.empty(), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void similarOptionals() {
+        ComponentDiff.compareOptionals(Optional.of("a"), Optional.of("a"), "foo", changes);
+        assertThat(changes).hasSize(0);
+    }
+
+    @Test
+    void differentOptionals() {
+        ComponentDiff.compareOptionals(Optional.of("a"), Optional.of("b"), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void similarCollections() {
+        ComponentDiff.compareCollections(List.of("a", "b"), List.of("b", "a"), "foo", changes);
+        assertThat(changes).hasSize(0);
+    }
+
+    @Test
+    void differentCollectionEntries() {
+        ComponentDiff.compareCollections(List.of("a", "b"), List.of("c", "a"), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void differentCollectionSize() {
+        ComponentDiff.compareCollections(List.of("a", "b"), List.of("a", "b", "c"), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+
+    @Test
+    void differentCollectionSize2() {
+        ComponentDiff.compareCollections(List.of("a", "b", "c"), List.of("a", "b"), "foo", changes);
+        assertThat(changes).hasSize(1);
+    }
+}