@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("{");
        if (getCollectionId() != null)
            sb.append("CollectionId: ").append(getCollectionId()).append(",");
        if (getUserId() != null)
            sb.append("UserId: ").append(getUserId()).append(",");
        if (getFaceIds() != null)
            sb.append("FaceIds: ").append(getFaceIds()).append(",");
        if (getUserMatchThreshold() != null)
            sb.append("UserMatchThreshold: ").append(getUserMatchThreshold()).append(",");
        if (getClientRequestToken() != null)
            sb.append("ClientRequestToken: ").append(getClientRequestToken());
        sb.append("}");
        return sb.toString();
    }
Returns a string representation of this object. This is useful for testing and debugging. Sensitive data will be
redacted from this string using a placeholder value.

@return A string representation of this object.

@see java.lang.Object#toString()
aws-java-sdk-rekognition/src/main/java/com/amazonaws/services/rekognition/model/AssociateFacesRequest.java