public void validate()

in main/src/main/java/org/apache/james/jdkim/tagvalue/SignatureRecordImpl.java [57:98]
30 lines of code
9 McCabe index (conditional complexity)

    public void validate() throws IllegalStateException {
        super.validate();
        // TODO: what about v=0.5 and no v= at all?
        // do specs allow parsing? what should we check?
        if (!"1".equals(getValue("v")))
            throw new IllegalStateException(
                    "Invalid DKIM-Signature version (expected '1'): "
                            + getValue("v"));
        if (getValue("h").length() == 0)
            throw new IllegalStateException("Tag h= cannot be empty.");

        CharSequence identity;
        try {
            identity = getIdentity();
        } catch (IllegalArgumentException e) {
            throw new IllegalStateException("Identity (i=) declaration cannot be parsed. Probably due to missing quoted printable encoding", e);
        }

        if (!identity.toString().toLowerCase().endsWith(
                ("@" + getValue("d")).toLowerCase())
                && !getIdentity().toString().toLowerCase().endsWith(
                ("." + getValue("d")).toLowerCase()))
            throw new IllegalStateException("Identity (i=) domain mismatch: expected [optional]@[optional.]domain-from-d-attribute");

        // when "x=" exists and signature expired then return PERMFAIL
        // (signature expired)
        if (getValue("x") != null) {
            long expiration = Long.parseLong(getValue("x").toString());
            long lifetime = (expiration - System.currentTimeMillis() / 1000);
            if (lifetime < 0) {
                throw new IllegalStateException("Signature is expired since "
                        + getTimeMeasure(lifetime) + ".");
            }
        }

        // when "h=" does not contain "from" return PERMFAIL (From field not
        // signed).
        if (!isInListCaseInsensitive("from", getHeaders()))
            throw new IllegalStateException("From field not signed");
        // TODO support ignoring signature for certain d values (externally to
        // this class).
    }