/// <summary>
        /// Encode interest using NDN-TLV and return the encoding.
        /// </summary>
        ///
        /// <param name="interest">The Interest object to encode.</param>
        /// <param name="signedPortionBeginOffset">name component and ends just before the final name component (which is assumed to be a signature for a signed interest).</param>
        /// <param name="signedPortionEndOffset">name component and ends just before the final name component (which is assumed to be a signature for a signed interest).</param>
        /// <returns>A Blob containing the encoding.</returns>
        public override Blob encodeInterest(Interest interest,
				int[] signedPortionBeginOffset, int[] signedPortionEndOffset)
        {
            TlvEncoder encoder = new TlvEncoder();
            int saveLength = encoder.getLength();

            // Encode backwards.
            encoder.writeOptionalNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SelectedDelegation,
                    interest.getSelectedDelegationIndex());
            try {
                Blob linkWireEncoding = interest.getLinkWireEncoding(this);
                if (!linkWireEncoding.isNull())
                    // Encode the entire link as is.
                    encoder.writeBuffer(linkWireEncoding.buf());
            } catch (EncodingException ex) {
                throw new Exception(ex.Message);
            }

            encoder.writeOptionalNonNegativeIntegerTlvFromDouble(
                    net.named_data.jndn.encoding.tlv.Tlv.InterestLifetime,
                    interest.getInterestLifetimeMilliseconds());

            // Encode the Nonce as 4 bytes.
            if (interest.getNonce().size() == 0) {
                // This is the most common case. Generate a nonce.
                ByteBuffer nonce = ILOG.J2CsMapping.NIO.ByteBuffer.allocate(4);
                random_.nextBytes(nonce.array());
                encoder.writeBlobTlv(net.named_data.jndn.encoding.tlv.Tlv.Nonce, nonce);
            } else if (interest.getNonce().size() < 4) {
                ByteBuffer nonce_0 = ILOG.J2CsMapping.NIO.ByteBuffer.allocate(4);
                // Copy existing nonce bytes.
                nonce_0.put(interest.getNonce().buf());

                // Generate random bytes for remaining bytes in the nonce.
                for (int i = 0; i < 4 - interest.getNonce().size(); ++i)
                    nonce_0.put((byte) random_.Next());

                nonce_0.flip();
                encoder.writeBlobTlv(net.named_data.jndn.encoding.tlv.Tlv.Nonce, nonce_0);
            } else if (interest.getNonce().size() == 4)
                // Use the nonce as-is.
                encoder.writeBlobTlv(net.named_data.jndn.encoding.tlv.Tlv.Nonce, interest.getNonce().buf());
            else {
                // Truncate.
                ByteBuffer nonce_1 = interest.getNonce().buf();
                // buf() returns a new ByteBuffer, so we can change its limit.
                nonce_1.limit(nonce_1.position() + 4);
                encoder.writeBlobTlv(net.named_data.jndn.encoding.tlv.Tlv.Nonce, nonce_1);
            }

            encodeSelectors(interest, encoder);
            int[] tempSignedPortionBeginOffset = new int[1];
            int[] tempSignedPortionEndOffset = new int[1];
            encodeName(interest.getName(), tempSignedPortionBeginOffset,
                    tempSignedPortionEndOffset, encoder);
            int signedPortionBeginOffsetFromBack = encoder.getLength()
                    - tempSignedPortionBeginOffset[0];
            int signedPortionEndOffsetFromBack = encoder.getLength()
                    - tempSignedPortionEndOffset[0];

            encoder.writeTypeAndLength(net.named_data.jndn.encoding.tlv.Tlv.Interest, encoder.getLength()
                    - saveLength);
            signedPortionBeginOffset[0] = encoder.getLength()
                    - signedPortionBeginOffsetFromBack;
            signedPortionEndOffset[0] = encoder.getLength()
                    - signedPortionEndOffsetFromBack;

            return new Blob(encoder.getOutput(), false);
        }
        /// <summary>
        /// An internal method to encode signature as the appropriate form of
        /// SignatureInfo in NDN-TLV.
        /// </summary>
        ///
        /// <param name="signature">An object of a subclass of Signature to encode.</param>
        /// <param name="encoder">The TlvEncoder to receive the encoding.</param>
        private void encodeSignatureInfo(Signature signature, TlvEncoder encoder)
        {
            if (signature  is  GenericSignature) {
                // Handle GenericSignature separately since it has the entire encoding.
                Blob encoding = ((GenericSignature) signature)
                        .getSignatureInfoEncoding();

                // Do a test decoding to sanity check that it is valid TLV.
                try {
                    TlvDecoder decoder = new TlvDecoder(encoding.buf());
                    int endOffset = decoder.readNestedTlvsStart(net.named_data.jndn.encoding.tlv.Tlv.SignatureInfo);
                    decoder.readNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SignatureType);
                    decoder.finishNestedTlvs(endOffset);
                } catch (EncodingException ex) {
                    throw new Exception(
                            "The GenericSignature encoding is not a valid NDN-TLV SignatureInfo: "
                                    + ex.Message);
                }

                encoder.writeBuffer(encoding.buf());
                return;
            }

            int saveLength = encoder.getLength();

            // Encode backwards.
            if (signature  is  Sha256WithRsaSignature) {
                if (((Sha256WithRsaSignature) signature).getValidityPeriod()
                        .hasPeriod())
                    encodeValidityPeriod(
                            ((Sha256WithRsaSignature) signature)
                                    .getValidityPeriod(),
                            encoder);
                encodeKeyLocator(net.named_data.jndn.encoding.tlv.Tlv.KeyLocator,
                        ((Sha256WithRsaSignature) signature).getKeyLocator(),
                        encoder);
                encoder.writeNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SignatureType,
                        net.named_data.jndn.encoding.tlv.Tlv.SignatureType_SignatureSha256WithRsa);
            } else if (signature  is  Sha256WithEcdsaSignature) {
                if (((Sha256WithEcdsaSignature) signature).getValidityPeriod()
                        .hasPeriod())
                    encodeValidityPeriod(
                            ((Sha256WithEcdsaSignature) signature)
                                    .getValidityPeriod(),
                            encoder);
                encodeKeyLocator(net.named_data.jndn.encoding.tlv.Tlv.KeyLocator,
                        ((Sha256WithEcdsaSignature) signature).getKeyLocator(),
                        encoder);
                encoder.writeNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SignatureType,
                        net.named_data.jndn.encoding.tlv.Tlv.SignatureType_SignatureSha256WithEcdsa);
            } else if (signature  is  HmacWithSha256Signature) {
                encodeKeyLocator(net.named_data.jndn.encoding.tlv.Tlv.KeyLocator,
                        ((HmacWithSha256Signature) signature).getKeyLocator(),
                        encoder);
                encoder.writeNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SignatureType,
                        net.named_data.jndn.encoding.tlv.Tlv.SignatureType_SignatureHmacWithSha256);
            } else if (signature  is  DigestSha256Signature)
                encoder.writeNonNegativeIntegerTlv(net.named_data.jndn.encoding.tlv.Tlv.SignatureType,
                        net.named_data.jndn.encoding.tlv.Tlv.SignatureType_DigestSha256);
            else
                throw new Exception(
                        "encodeSignatureInfo: Unrecognized Signature object type");

            encoder.writeTypeAndLength(net.named_data.jndn.encoding.tlv.Tlv.SignatureInfo, encoder.getLength()
                    - saveLength);
        }