code: public static RuleViolation isInputStandard(TransactionInput input) {
          for (ScriptChunk chunk : input.getScriptSig().getChunks()) {
              if (chunk.data != null && !chunk.isShortestPossiblePushData())
                  return RuleViolation.SHORTEST_POSSIBLE_PUSHDATA;
              if (chunk.isPushData()) {
                  ECDSASignature signature;
                  try {
                      signature = ECKey.ECDSASignature.decodeFromDER(chunk.data);
                  } catch (SignatureDecodeException x) {
                      // Doesn't look like a signature.
                      signature = null;
                  }
                  if (signature != null) {
                      if (!TransactionSignature.isEncodingCanonical(chunk.data))
                          return RuleViolation.SIGNATURE_CANONICAL_ENCODING;
                      if (!signature.isCanonical())
                          return RuleViolation.SIGNATURE_CANONICAL_ENCODING;
                  }
              }
          }
          return RuleViolation.NONE;
      }
docs: Checks if the given input passes some of the AreInputsStandard checks. Not complete.