static SymbolTable newSharedSymbolTable()

in src/com/amazon/ion/impl/SharedSymbolTable.java [206:320]
88 lines of code
20 McCabe index (conditional complexity)

    static SymbolTable newSharedSymbolTable(IonReader reader,
                                            boolean isOnStruct)
    {
        if (! isOnStruct)
        {
            IonType t = reader.next();
            if (t != IonType.STRUCT)
            {
                throw new IonException("invalid symbol table image passed " +
                                "into reader, " + t + " encountered when a " +
                                "struct was expected");
            }
        }

        String name = null;
        int version = -1;
        List<String> symbolsList = new ArrayList<String>();

        reader.stepIn();

        IonType fieldType = null;
        while ((fieldType = reader.next()) != null)
        {
            if (reader.isNullValue()) continue;

            SymbolToken symTok = reader.getFieldNameSymbol();
            int sid = symTok.getSid();
            if (sid == SymbolTable.UNKNOWN_SYMBOL_ID)
            {
                // This is a user-defined IonReader or a pure DOM, fall
                // back to text
                final String fieldName = reader.getFieldName();
                sid = getSidForSymbolTableField(fieldName);
            }

            // TODO amzn/ion-java/issues/35 If there's more than one 'symbols' or 'imports'
            //      field, they will be merged together.
            // TODO amzn/ion-java/issues/36 Switching over SIDs doesn't cover the case
            //      where the relevant field names are defined by a prev LST;
            //      the prev LST could have 'symbols' defined locally with a
            //      different SID!
            switch (sid)
            {
                case VERSION_SID:
                    if (fieldType == IonType.INT)
                    {
                        version = reader.intValue();
                    }
                    break;
                case NAME_SID:
                    if (fieldType == IonType.STRING)
                    {
                        name = reader.stringValue();
                    }
                    break;
                case SYMBOLS_SID:
                    // As per the Spec, other field types are treated as
                    // empty lists
                    if (fieldType == IonType.LIST)
                    {
                        reader.stepIn();
                        {
                            IonType t;
                            while ((t = reader.next()) != null)
                            {
                                String text = null;
                                if (t == IonType.STRING
                                    && ! reader.isNullValue())
                                {
                                    // As per the Spec, if any element of
                                    // the list is the empty string or any
                                    // other type, treat it as null
                                    text = reader.stringValue();
                                    if (text.length() == 0) text = null;
                                }
                                symbolsList.add(text);
                            }
                        }
                        reader.stepOut();
                    }
                    break;
                default:
                    break;
            }
        }

        reader.stepOut();

        if (name == null || name.length() == 0)
        {
            String message =
                "shared symbol table is malformed: field 'name' " +
                "must be a non-empty string.";
            throw new IonException(message);
        }

        // As per the Spec, if 'version' field is missing or not at
        // least 1, treat it as 1.
        version = (version < 1) ? 1 : version;

        Map<String, Integer> symbolsMap = null;
        if (! symbolsList.isEmpty())
        {
            symbolsMap = new HashMap<String, Integer>();
            transferNonExistingSymbols(symbolsList, symbolsMap);
        }
        else
        {
            // Empty Map is more efficient than an empty HashMap
            symbolsMap = Collections.emptyMap();
        }

        // We have all necessary data, pass it over to the private constructor.
        return new SharedSymbolTable(name, version, symbolsList, symbolsMap);
    }