title: Swagger Codegen: Inheritance and Composition not working as expected
body: <p>I have the following short YAML:</p>
  
  <pre><code># Transaction Request object with minimal information that we need
    Parent:
      required:
    - a
    - b
    - c
  properties:
    a:
      type: number
      format: double
    b:
      type: string
    c:
      type: string
  
  # Full transaction
  Child:
  required:
    - a 
    - b
    - c
  allOf:
    - $ref: "#/definitions/Parent"
  properties:    
    date: 
      type: string 
      format: date-time
    state: 
      type: string 
      enum: 
        - 1
        - 2
        - 3
  </code></pre>
  
  <p>In Swagger UI and Editor these objects show up as I wish them to: <code>Child</code> inherits the <code>a</code>,<code>b</code> and <code>c</code> fields from <code>Parent</code> and has a few additional ones.</p>
  
  <p>I would have expected:</p>
  
  <pre><code>public class Parent {
  
    private Double a;
    private String b;
    private String c;
  
    ...}
  </code></pre>
  
  <p>and</p>
  
  <pre><code> public class Child extends Parent {
  
   // Superclass fields as well as:
   private Date date;
   private enum State {...};
  
    ...}
  </code></pre>
  
  <p>However, while the <code>Parent</code> class looked as expected, my <code>Child</code> class consisted of the following:</p>
  
  <pre><code>public class Child   {
  
  
  
  @Override
  public boolean equals(Object o) {
  if (this == o) {
    return true;
  }
  if (o == null || getClass() != o.getClass()) {
    return false;
  }
  Child child = (Child) o;
  return true;
  }
  
  ... }
  </code></pre>
  
  <p>Which lacks even <code>extends</code>. When using a <code>discriminator</code> it works, but I don't really want Polymorphism - just plain inheritance. How can I accomplish this with Swagger Codegen?</p>
  
  <hr>
  
  <p>Relevant <code>pom.xml</code> entry:</p>
  
  <pre><code>            &lt;plugin&gt;
                  &lt;groupId&gt;io.swagger&lt;/groupId&gt;
                  &lt;artifactId&gt;swagger-codegen-maven-plugin&lt;/artifactId&gt;
                  &lt;version&gt;2.2.2-SNAPSHOT&lt;/version&gt;
  
                  &lt;configuration&gt;
                      &lt;inputSpec&gt;${project.basedir}/src/main/resources/test.yaml&lt;/inputSpec&gt;
                      &lt;language&gt;jaxrs-resteasy&lt;/language&gt;
                      &lt;output&gt;${project.build.directory}/generated-sources/payment&lt;/output&gt;
  
                      &lt;configOptions&gt;
                          &lt;sourceFolder&gt;src/java/main&lt;/sourceFolder&gt;
                          &lt;dateLibrary&gt;java8&lt;/dateLibrary&gt;
                      &lt;/configOptions&gt;
  
                      &lt;groupId&gt;net.product&lt;/groupId&gt;
                      &lt;artifactId&gt;product_api&lt;/artifactId&gt;
                      &lt;modelPackage&gt;net.product.product_api.model&lt;/modelPackage&gt;
                      &lt;invokerPackage&gt;net.product.product_api&lt;/invokerPackage&gt;
                      &lt;apiPackage&gt;net.product.product_api&lt;/apiPackage&gt;
                  &lt;/configuration&gt;
  
                  &lt;executions&gt;
  
                      &lt;execution&gt;
                          &lt;id&gt;generate-server-stubs&lt;/id&gt;
                          &lt;goals&gt;
                              &lt;goal&gt;generate&lt;/goal&gt;
                          &lt;/goals&gt;
                          &lt;configuration&gt;
                          &lt;/configuration&gt;
                      &lt;/execution&gt;
  
                  &lt;/executions&gt;
  
              &lt;/plugin&gt;
  </code></pre>