feat: Add DuplicateFinder

Author: larshelge

src/main/java/org/hisp/dhis/util/CollectionUtils.java

@@ -34,11 +34,15 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for collections.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class CollectionUtils {
   /**
@@ -100,6 +104,21 @@ public static <T> List<T> mutableList(T... items) {
 
     return list;
   }
+  
+  /**
+   * Maps the given list of objects of type <U> to a list of objects of type <T>. Null objects are not allowed.
+   * 
+   * @param <T> type.
+   * @param <U> type.
+   * @param objects the objects of type <U>.
+   * @param mapper the mapping function.
+   * @return a list of objects of type <T>.
+   */
+  public static <T, U> List<T> mapToList(List<U> objects, Function<U, T> mapper) {
+    return objects.stream()
+        .map(mapper)
+        .toList();
+  }
 
   /**
    * Converts the given array to an {@link ArrayList}.

src/main/java/org/hisp/dhis/util/ConfigUtils.java

@@ -31,11 +31,14 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
 import org.apache.commons.lang3.ObjectUtils;
 import org.apache.commons.lang3.StringUtils;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for configuration.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class ConfigUtils {
   /**

src/main/java/org/hisp/dhis/util/DateTimeUtils.java

@@ -35,10 +35,13 @@
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
+import org.apache.commons.lang3.StringUtils;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
-import org.apache.commons.lang3.StringUtils;
 
+/**
+ * Utilities for date and time.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class DateTimeUtils {
   private static final String DATE_TIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSS";

src/main/java/org/hisp/dhis/util/DuplicateFinder.java

@@ -0,0 +1,64 @@
+package org.hisp.dhis.util;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Duplicate value finder.
+ */
+public class DuplicateFinder {
+
+  private Map<String, Integer> valueCounts;
+
+  /**
+   * Constructor.
+   */
+  public DuplicateFinder() {
+    this.valueCounts = new HashMap<>();
+  }
+
+  /**
+   * Constructor.
+   * 
+   * @param values the collection of values.
+   */
+  public DuplicateFinder(Collection<String> values) {
+    this();
+    addAll(values);
+  }
+
+  /**
+   * Adds a value.
+   *
+   * @param value the value.
+   */
+  public void add(String value) {
+    valueCounts.put(value, valueCounts.getOrDefault(value, 0) + 1);
+  }
+  
+  /**
+   * Adds a collection of values.
+   * 
+   * @param values the values.
+   */
+  public void addAll(Collection<String> values) {
+    values.forEach(value -> add(value));
+  }
+
+  /**
+   * Returns the duplicates as a map, where the key is the duplicate value and the value is the
+   * number of occurrences.
+   *
+   * @return the duplicates as a map.
+   */
+  public Map<String, Integer> getDuplicates() {
+    Map<String, Integer> duplicates = new HashMap<>();
+    for (Map.Entry<String, Integer> entry : valueCounts.entrySet()) {
+      if (entry.getValue() > 1) {
+        duplicates.put(entry.getKey(), entry.getValue());
+      }
+    }
+    return duplicates;
+  }
+}

src/main/java/org/hisp/dhis/util/GeoUtils.java

@@ -27,12 +27,15 @@
  */
 package org.hisp.dhis.util;
 
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.GeometryFactory;
 import org.locationtech.jts.geom.Point;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for geospatial objects.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class GeoUtils {
   private static final GeometryFactory GEO_FACTORY = new GeometryFactory();

src/main/java/org/hisp/dhis/util/HttpUtils.java

@@ -32,14 +32,17 @@
 import java.net.URISyntaxException;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
 import org.apache.hc.client5.http.classic.methods.HttpUriRequestBase;
 import org.apache.hc.core5.http.message.BasicHttpRequest;
 import org.apache.hc.core5.net.URIBuilder;
 import org.hisp.dhis.Dhis2Config;
 import org.hisp.dhis.auth.Authentication;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for HTTP communication.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class HttpUtils {
   /**

src/main/java/org/hisp/dhis/util/IdentifiableObjectUtils.java

@@ -31,10 +31,13 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.stream.Collectors;
+import org.hisp.dhis.model.IdentifiableObject;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
-import org.hisp.dhis.model.IdentifiableObject;
 
+/**
+ * Utilities for {@link IdentifiableObject}.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class IdentifiableObjectUtils {
   /**

src/main/java/org/hisp/dhis/util/JacksonUtils.java

@@ -27,18 +27,21 @@
  */
 package org.hisp.dhis.util;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UncheckedIOException;
+import java.text.SimpleDateFormat;
 import com.bedatadriven.jackson.datatype.jts.JtsModule;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.UncheckedIOException;
-import java.text.SimpleDateFormat;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for JSON parsing and serialization.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class JacksonUtils {
   /** Default date format. */

src/main/java/org/hisp/dhis/util/ListBuilder.java

@@ -32,6 +32,19 @@
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Builder of lists.
+ * 
+ * <p>Example usage:
+ *
+ * <pre>{@code
+ * List<T> = new ListBuilder<T>()
+ *   .add(valueA)
+ *   .add(valueB, valueC)
+ *   .addAll(List.of(valueD, valueE))
+ *   .build();
+ * }</pre>
+ */
 public class ListBuilder<T> {
   private final List<T> list;
 

src/main/java/org/hisp/dhis/util/UidUtils.java

@@ -32,6 +32,9 @@
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 
+/**
+ * Utilities for UID.
+ */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class UidUtils {
   private static final String ALPHABET = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";