graphdb/src/main/java/com/tinkerpop/blueprints/impls/orient/OrientBaseGraph.java
public Iterable<Vertex> getVerticesOfClass(final String iClassName, final boolean iPolymorphic) {
    makeActive();

    final OClass cls = getRawGraph().getMetadata().getSchema().getClass(iClassName);
    if (cls == null)
      throw new IllegalArgumentException("Cannot find class '" + iClassName + "' in database schema");

    if (!cls.isSubClassOf(OrientVertexType.CLASS_NAME))
      throw new IllegalArgumentException("Class '" + iClassName + "' is not a vertex class");

    return new OrientElementScanIterable<Vertex>(this, iClassName, iPolymorphic);
  }
public Iterable<Vertex> getVerticesOfClass(final String iClassName, final boolean iPolymorphic) {
    makeActive();

    final OClass cls = getRawGraph().getMetadata().getSchema().getClass(iClassName);
    if (cls == null)
      throw new IllegalArgumentException("Cannot find class '" + iClassName + "' in database schema");

    if (!cls.isSubClassOf(OrientVertexType.CLASS_NAME))
      throw new IllegalArgumentException("Class '" + iClassName + "' is not a vertex class");

    return new OrientElementScanIterable<Vertex>(this, iClassName, iPolymorphic);
  }
Get all the Vertices in Graph of a specific vertex class and all sub-classes only if iPolymorphic is true.

@param iClassName   Vertex class name to filter
@param iPolymorphic If true consider also Vertex iClassName sub-classes

@return Vertices as Iterable