graphdb/src/main/java/com/tinkerpop/blueprints/impls/orient/OrientElement.java
public final void validateProperty(final Element element, final String key, final Object value) throws IllegalArgumentException {
    if (settings.isStandardElementConstraints() && null == value)
      throw ExceptionFactory.propertyValueCanNotBeNull();
    if (null == key)
      throw ExceptionFactory.propertyKeyCanNotBeNull();
    if (settings.isStandardElementConstraints() && key.equals(StringFactory.ID))
      throw ExceptionFactory.propertyKeyIdIsReserved();
    if (element instanceof Edge && key.equals(StringFactory.LABEL))
      throw ExceptionFactory.propertyKeyLabelIsReservedForEdges();
    if (key.isEmpty())
      throw ExceptionFactory.propertyKeyCanNotBeEmpty();
  }
public final void validateProperty(final Element element, final String key, final Object value) throws IllegalArgumentException {
    if (settings.isStandardElementConstraints() && null == value)
      throw ExceptionFactory.propertyValueCanNotBeNull();
    if (null == key)
      throw ExceptionFactory.propertyKeyCanNotBeNull();
    if (settings.isStandardElementConstraints() && key.equals(StringFactory.ID))
      throw ExceptionFactory.propertyKeyIdIsReserved();
    if (element instanceof Edge && key.equals(StringFactory.LABEL))
      throw ExceptionFactory.propertyKeyLabelIsReservedForEdges();
    if (key.isEmpty())
      throw ExceptionFactory.propertyKeyCanNotBeEmpty();
  }
(Blueprints Extension) Validates an Element property.

@param element Element instance
@param key     Property name
@param value   property value
@throws IllegalArgumentException