De-duplicate identical classes and avoid __1

jsonschema2pojo-ant/src/main/java/org/jsonschema2pojo/ant/Jsonschema2PojoTask.java

@@ -196,6 +196,9 @@ public class Jsonschema2PojoTask extends Task implements GenerationConfig {
     private boolean includeGeneratedAnnotation = true;
 
     private boolean useJakartaValidation = false;
+
+    private boolean useDeduplication = false;
+
     /**
      * Execute this task (it's expected that all relevant setters will have been
      * called by Ant to provide task configuration <em>before</em> this method
@@ -977,6 +980,15 @@ public void setUseJakartaValidation(boolean useJakartaValidation) {
         this.useJakartaValidation = useJakartaValidation;
     }
 
+    /**
+     * Sets the 'useDeduplication' property of this class
+     *
+     * @param useDeduplication Whether to deduplicate generated types for identical schemas.
+     */
+    public void setUseDeduplication(boolean useDeduplication) {
+        this.useDeduplication = useDeduplication;
+    }
+
     public void setFormatTypeMapping(Map<String, String> formatTypeMapping) {
         this.formatTypeMapping = formatTypeMapping;
     }
@@ -1338,4 +1350,9 @@ public boolean isIncludeGeneratedAnnotation() {
     public boolean isUseJakartaValidation() {
         return useJakartaValidation;
     }
+
+    @Override
+    public boolean isUseDeduplication() {
+        return useDeduplication;
+    }
 }

jsonschema2pojo-ant/src/site/Jsonschema2PojoTask.html

@@ -632,6 +632,11 @@ <h3>Parameters</h3>
       </td>
       <td align="center" valign="top">No (default <code>false</code>)</td>
   </tr>
+  <tr>
+    <td valign="top">useDeduplication</td>
+    <td valign="top">Deduplicates Java classes and enums if they have identical schemas.</td>
+    <td align="center" valign="top">No (default <code>false</code>)</td>
+  </tr>
 </table>
 <h3>Examples</h3>
 <pre>

jsonschema2pojo-cli/src/main/java/org/jsonschema2pojo/cli/Arguments.java

@@ -251,6 +251,9 @@ public class Arguments implements GenerationConfig {
     @Parameter(names = { "--useJakartaValidation" }, description = "Whether to use annotations from jakarta.validation package instead of javax.validation package when adding JSR-303/349 annotations to generated Java types")
     private boolean useJakartaValidation = false;
 
+    @Parameter(names = { "--useDeduplication" }, description = "Whether to deduplicate generated types for identical schemas")
+    private boolean useDeduplication = false;
+
     @Parameter(names = { "-v", "--version"}, description = "Print version information", help = true)
     private boolean printVersion = false;
 
@@ -624,4 +627,9 @@ public boolean isIncludeGeneratedAnnotation() {
     public boolean isUseJakartaValidation() {
         return useJakartaValidation;
     }
+
+    @Override
+    public boolean isUseDeduplication() {
+        return useDeduplication;
+    }
 }

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/DefaultGenerationConfig.java

@@ -495,4 +495,12 @@ public boolean isIncludeGeneratedAnnotation() {
     public boolean isUseJakartaValidation() {
         return false;
     }
+
+    /**
+     * @return {@code false}
+     */
+    @Override
+    public boolean isUseDeduplication() {
+        return false;
+    }
 }

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/GenerationConfig.java

@@ -635,4 +635,11 @@ default boolean isUseInnerClassBuilders() {
    */
   boolean isUseJakartaValidation();
 
+  /**
+   * Deduplicates Java classes and enums if they have identical schemas.
+   *
+   * @return Whether to perform deduplication.
+   */
+  boolean isUseDeduplication();
+
 }

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/Schema.java

@@ -17,6 +17,11 @@
 package org.jsonschema2pojo;
 
 import java.net.URI;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Base64;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.sun.codemodel.JType;
@@ -75,4 +80,13 @@ public boolean isGenerated() {
         return javaType != null;
     }
 
+    public String calculateHash() {
+        try {
+            return Base64.getEncoder()
+                    .encodeToString(MessageDigest.getInstance("SHA-256")
+                            .digest(content.toString().getBytes(StandardCharsets.UTF_8)));
+        } catch (NoSuchAlgorithmException ex) {
+            throw new RuntimeException("SHA-256 not available, disable de-duplication to avoid", ex);
+        }
+    }
 }

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/DeduplicateRule.java

@@ -0,0 +1,61 @@
+/**
+ * Copyright © 2024 Nokia
+ *
+ * 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
+ *
+ *      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.jsonschema2pojo.rules;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import org.jsonschema2pojo.Schema;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Wraps an existing Rule and performs deduplication of identical schemas to the same output.
+ */
+class DeduplicateRule<T, R> implements Rule<T, R> {
+
+    private final Map<String, R> deduplicateCache;
+    private final Rule<T, R> rule;
+
+    public DeduplicateRule(Map<Class<?>, Map<String, ?>> dedupeCacheByRule, Rule<T, R> rule) {
+        // noinspection unchecked map is populated by us and guaranteed to be of the correct type
+        Map<String, R> dedupeCache = (Map<String, R>) dedupeCacheByRule.get(rule.getClass());
+        if(dedupeCache == null) {
+            dedupeCache = new HashMap<>();
+            dedupeCacheByRule.put(rule.getClass(), dedupeCache);
+        }
+        this.deduplicateCache = dedupeCache;
+        this.rule = rule;
+    }
+
+    /**
+     * Deduplicates based on {@link Schema#calculateHash()} and returns identical {@code R} instances.
+     *
+     * @param currentSchema
+     *            schema to be used for deduplication
+     * @return same {@code R} instance if a previous schema with the same hash code was already processed
+     */
+    @Override
+    public R apply(String nodeName, JsonNode node, JsonNode parent, T generatableType, Schema currentSchema) {
+        String hash = currentSchema.calculateHash();
+        R output = deduplicateCache.get(hash);
+        if (output == null) {
+            output = rule.apply(nodeName, node, parent, generatableType, currentSchema);
+            deduplicateCache.put(hash, output);
+        }
+        return output;
+    }
+}

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/RuleFactory.java

@@ -36,6 +36,9 @@
 import com.sun.codemodel.JPackage;
 import com.sun.codemodel.JType;
 
+import java.util.HashMap;
+import java.util.Map;
+
 /**
  * Provides factory/creation methods for the code generation rules.
  */
@@ -47,6 +50,7 @@ public class RuleFactory {
     private GenerationConfig generationConfig;
     private Annotator annotator;
     private SchemaStore schemaStore;
+    private Map<Class<?>, Map<String, ?>> dedupeCache;
 
     /**
      * Create a new rule factory with the given generation config options.
@@ -68,6 +72,7 @@ public RuleFactory(GenerationConfig generationConfig, Annotator annotator, Schem
         this.nameHelper = new NameHelper(generationConfig);
         this.reflectionHelper = new ReflectionHelper(this);
         this.logger = new NoopRuleLogger();
+        this.dedupeCache = new HashMap<>();
     }
 
     /**
@@ -116,7 +121,11 @@ public Rule<JDocCommentable, JDocComment> getCommentRule() {
      * @return a schema rule that can handle the "enum" declaration.
      */
     public Rule<JClassContainer, JType> getEnumRule() {
-        return new EnumRule(this);
+        Rule<JClassContainer, JType> rule = new EnumRule(this);
+        if (generationConfig.isUseDeduplication()) {
+            rule = new DeduplicateRule<>(dedupeCache, rule);
+        }
+        return rule;
     }
 
     /**
@@ -136,7 +145,11 @@ public Rule<JType, JType> getFormatRule() {
      * @return a schema rule that can handle the "object" declaration.
      */
     public Rule<JPackage, JType> getObjectRule() {
-        return new ObjectRule(this, new ParcelableHelper(), reflectionHelper);
+        Rule<JPackage, JType> rule = new ObjectRule(this, new ParcelableHelper(), reflectionHelper);
+        if (generationConfig.isUseDeduplication()) {
+            rule = new DeduplicateRule<>(dedupeCache, rule);
+        }
+        return rule;
     }
 
     /**

jsonschema2pojo-core/src/test/java/org/jsonschema2pojo/rules/DeduplicateRuleTest.java

@@ -0,0 +1,92 @@
+/**
+ * Copyright © 2024 Nokia
+ *
+ * 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
+ *
+ *      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.jsonschema2pojo.rules;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.collect.ImmutableMap;
+import com.sun.codemodel.JCodeModel;
+import com.sun.codemodel.JPackage;
+import com.sun.codemodel.JType;
+import org.jsonschema2pojo.Annotator;
+import org.jsonschema2pojo.RuleLogger;
+import org.jsonschema2pojo.Schema;
+import org.jsonschema2pojo.util.NameHelper;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.ArgumentMatchers;
+import org.mockito.stubbing.Answer;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.mockito.Mockito.*;
+
+public class DeduplicateRuleTest {
+
+    private Map<String, UUID> dedupeCache;
+    private Rule<Object, UUID> dedupeRule;
+
+    @Before
+    public void setupRule() {
+        dedupeCache = new HashMap<>();
+        DummyRule dummyRule = new DummyRule();
+        dedupeRule = new DeduplicateRule<>(ImmutableMap.of(dummyRule.getClass(), dedupeCache), dummyRule);
+    }
+
+    @Test
+    public void test() {
+
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        ArrayNode arrayNode1 = objectMapper.createArrayNode().add(7).add(8);
+        ArrayNode arrayNode2 = objectMapper.createArrayNode().add(7).add(8);
+        ArrayNode arrayNode3 = objectMapper.createArrayNode().add(7).add(9);
+        assertEquals(arrayNode1.toString(), arrayNode2.toString());
+        assertNotEquals(arrayNode1.toString(), arrayNode3.toString());
+
+        Schema schema1 = new Schema(null, arrayNode1, null);
+        Schema schema2 = new Schema(null, arrayNode2, null);
+        Schema schema3 = new Schema(null, arrayNode3, null);
+        assertEquals(schema1.calculateHash(), schema1.calculateHash());
+        assertEquals(schema1.calculateHash(), schema2.calculateHash());
+        assertNotEquals(schema1.calculateHash(), schema3.calculateHash());
+
+        UUID uuid1 = dedupeRule.apply(null, null, null, null, schema1);
+        UUID uuid2 = dedupeRule.apply(null, null, null, null, schema1);
+        UUID uuid3 = dedupeRule.apply(null, null, null, null, schema2);
+        UUID uuid4 = dedupeRule.apply(null, null, null, null, schema3);
+
+        assertEquals(uuid1, uuid2);
+        assertEquals(uuid1, uuid3);
+        assertNotEquals(uuid1, uuid4);
+    }
+
+    public static class DummyRule implements Rule<Object, UUID> {
+        @Override
+        public UUID apply(String nodeName, JsonNode node, JsonNode parent, Object generatableType, Schema currentSchema) {
+            return UUID.randomUUID();
+        }
+    }
+}

jsonschema2pojo-gradle-plugin/README.md

@@ -315,6 +315,9 @@ jsonSchema2Pojo {
   // Whether to use annotations from jakarta.validation package instead of javax.validation package
   // when adding JSR-303 annotations to generated Java types
   useJakartaValidation = false
+
+  // Deduplicates Java classes and enums if they have identical schemas.
+  useDeduplication = false
 }
 ```
 

jsonschema2pojo-gradle-plugin/src/main/groovy/org/jsonschema2pojo/gradle/JsonSchemaExtension.groovy

@@ -98,6 +98,7 @@ public class JsonSchemaExtension implements GenerationConfig {
   Map<String, String> formatTypeMapping
   boolean includeGeneratedAnnotation
   boolean useJakartaValidation
+  boolean useDeduplication
 
   public JsonSchemaExtension() {
     // See DefaultGenerationConfig
@@ -158,6 +159,7 @@ public class JsonSchemaExtension implements GenerationConfig {
     formatTypeMapping = Collections.emptyMap()
     includeGeneratedAnnotation = true
     useJakartaValidation = false
+    useDeduplication = false
   }
 
   @Override
@@ -292,6 +294,7 @@ public class JsonSchemaExtension implements GenerationConfig {
        |includeConstructorPropertiesAnnotation = ${includeConstructorPropertiesAnnotation}
        |includeGeneratedAnnotation = ${includeGeneratedAnnotation}
        |useJakartaValidation = ${useJakartaValidation}
+       |useDeduplication = ${useDeduplication}
      """.stripMargin()
   }
 

jsonschema2pojo-integration-tests/src/test/java/org/jsonschema2pojo/integration/json/JsonTypesIT.java

@@ -261,4 +261,27 @@ public void propertiesWithSameNameOnDifferentObjects() throws Exception {
 
     }
 
+    @Test
+    public void propertiesWithSameNameOnDifferentObjectsWithDedupe() throws Exception {
+
+        final String filePath = "/" + format + "/commonSubClasses";
+        ClassLoader resultsClassLoader = schemaRule.generateAndCompile(filePath, "com.example", config("sourceType", format, "useDeduplication", true));
+
+        Class<?> aType = resultsClassLoader.loadClass("com.example.A");
+        Class<?> bType = resultsClassLoader.loadClass("com.example.B");
+
+        Object deserializedValueA = objectMapper.readValue(this.getClass().getResourceAsStream(filePath("commonSubClasses/a")), aType);
+        Object deserializedValueB = objectMapper.readValue(this.getClass().getResourceAsStream(filePath("commonSubClasses/b")), bType);
+
+        assertNotEquals(aType.getMethod("getAa").getReturnType().getName(),
+                bType.getMethod("getAa").getReturnType().getName());
+        assertEquals(aType.getMethod("get1").getReturnType().getName(),
+                bType.getMethod("get1").getReturnType().getName());
+
+        Object a1 = aType.getMethod("get1").invoke(deserializedValueA);
+        Object b1 = bType.getMethod("get1").invoke(deserializedValueB);
+
+        assertEquals(a1.getClass().getMethod("get3").getReturnType().getName(),
+                b1.getClass().getMethod("get3").getReturnType().getName());
+    }
 }

jsonschema2pojo-integration-tests/src/test/resources/json/commonSubClasses/a.json

@@ -0,0 +1,9 @@
+{
+  "aa" : {
+    "aaa" : "aaaa"
+  },
+  "1" : {
+    "2" : {},
+    "3" : [1, 2, 3]
+  }
+}