Allow trailing comma.

src/it/allowed-trailing-comma/invoker.properties

@@ -0,0 +1 @@
+invoker.buildResult = success

src/it/allowed-trailing-comma/pom.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.github.sylvainlaurent.maven.it</groupId>
+  <artifactId>validate-it</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>@project.groupId@</groupId>
+        <artifactId>@project.artifactId@</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <id>validate</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <allowTrailingComma>true</allowTrailingComma>
+              <validationSets>
+                <validationSet>
+                  <includes>
+                    <include>src/main/resources/*.yml</include>
+                    <include>src/main/resources/*.json</include>
+                  </includes>
+                </validationSet>
+              </validationSets>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/allowed-trailing-comma/src/main/resources/trailing-comma.json

@@ -0,0 +1,4 @@
+{
+  "list": [1, 2,],
+  "second": 1,
+}

src/it/allowed-trailing-comma/src/main/resources/trailing-comma.yml

@@ -0,0 +1,3 @@
+root:
+  list: [1, 2,]
+  dict: { value: key, value2: key2, }

src/it/duplicate-keys-json/invoker.properties

@@ -0,0 +1 @@
+invoker.buildResult = failure

src/it/duplicate-keys-json/pom.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.github.sylvainlaurent.maven.it</groupId>
+  <artifactId>validate-it</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>@project.groupId@</groupId>
+        <artifactId>@project.artifactId@</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <id>validate</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <detectDuplicateKeys>true</detectDuplicateKeys>
+              <validationSets>
+                <validationSet>
+                  <includes>
+                    <include>src/main/resources/*.json</include>
+                  </includes>
+                </validationSet>
+              </validationSets>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/duplicate-keys-json/src/main/resources/duplicate-keys.json

@@ -0,0 +1,5 @@
+{
+  "id": 1,
+  "value": "XYZ",
+  "id": 2
+}

src/it/duplicate-keys-yaml/invoker.properties

@@ -0,0 +1 @@
+invoker.buildResult = failure

src/it/duplicate-keys-yaml/pom.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.github.sylvainlaurent.maven.it</groupId>
+  <artifactId>validate-it</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>@project.groupId@</groupId>
+        <artifactId>@project.artifactId@</artifactId>
+        <version>@project.version@</version>
+        <executions>
+          <execution>
+            <id>validate</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>validate</goal>
+            </goals>
+            <configuration>
+              <detectDuplicateKeys>true</detectDuplicateKeys>
+              <validationSets>
+                <validationSet>
+                  <includes>
+                    <include>src/main/resources/*.yml</include>
+                  </includes>
+                </validationSet>
+              </validationSets>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

src/it/duplicate-keys-yaml/src/main/resources/duplicate-keys.yml

@@ -0,0 +1,5 @@
+item:
+  id: 1
+  value: XYZ
+  id: 2
+

src/it/validate-succeeds/src/main/resources/swagger-editor-example.yml

@@ -1,6 +1,9 @@
 # this is an example of the Uber API
 # as a demonstration of an API spec in YAML
 swagger: '2.0'
+# Intentional duplicate here to make sure it passes validation
+# if detection of duplicate keys is not enabled:
+swagger: '2.0'
 info:
   title: Uber API
   description: Move your app forward with the Uber API

src/main/java/com/github/sylvainlaurent/maven/yamljsonvalidator/ValidateMojo.java

@@ -52,6 +52,18 @@ public class ValidateMojo extends AbstractMojo {
     @Parameter(name = "allowEmptyFiles", defaultValue = "false")
     private boolean allowEmptyFiles;
 
+    /**
+     * Set to <code>true</code> to detect duplicate keys in JSON and YAML dictionaries.
+     */
+    @Parameter(defaultValue = "false")
+    private boolean detectDuplicateKeys;
+
+    /**
+     * Set to <code>true</code> to allow for single trailing comma following final value or member.
+     */
+    @Parameter(defaultValue = "false")
+    private boolean allowTrailingComma;
+
     @Override
     public void execute() throws MojoExecutionException {
         boolean encounteredError = false;
@@ -63,7 +75,7 @@ public void execute() throws MojoExecutionException {
 
         for (final ValidationSet set : validationSets) {
             final ValidationService validationService = new ValidationService(set.getJsonSchema(),
-                allowEmptyFiles);
+                allowEmptyFiles, detectDuplicateKeys, allowTrailingComma);
 
             final File[] files = set.getFiles(basedir);
 

src/main/java/com/github/sylvainlaurent/maven/yamljsonvalidator/ValidationService.java

@@ -3,6 +3,7 @@
 import java.io.File;
 import java.io.IOException;
 
+import com.fasterxml.jackson.core.JsonParser.Feature;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
@@ -22,13 +23,22 @@ public class ValidationService {
 
     private final boolean isEmptyFileAllowed;
 
-    public ValidationService(final File schemaFile, final boolean isEmptyFileAllowed) {
+    public ValidationService(final File schemaFile, final boolean isEmptyFileAllowed,
+        final boolean detectDuplicateKeys, final boolean allowTrailingComma) {
         schema = getJsonSchema(schemaFile);
         this.isEmptyFileAllowed = isEmptyFileAllowed;
+        if (detectDuplicateKeys) {
+            this.jsonMapper.enable(Feature.STRICT_DUPLICATE_DETECTION);
+            this.yamlMapper.enable(Feature.STRICT_DUPLICATE_DETECTION);
+        }
+        if (allowTrailingComma) {
+            this.jsonMapper.enable(Feature.ALLOW_TRAILING_COMMA);
+            this.yamlMapper.enable(Feature.ALLOW_TRAILING_COMMA);
+        }
     }
 
     public ValidationService(final File schemaFile) {
-        this(schemaFile, false);
+        this(schemaFile, false, false, false);
     }
 
     public ValidationResult validate(final File file) {

src/test/java/com/github/sylvainlaurent/maven/yamljsonvalidator/ValidationServiceAllowEmptyFilesTest.java

@@ -8,7 +8,7 @@
 import static org.junit.Assert.*;
 
 public class ValidationServiceAllowEmptyFilesTest {
-    private ValidationService service = new ValidationService(null, true);
+    private ValidationService service = new ValidationService(null, true, false, false);
 
     @Test
     public void test_empty_file_yml() {