private void buildCollationMapping()

in src/main/core-impl/java/com/mysql/cj/NativeCharsetSettings.java [511:645]
123 lines of code
22 McCabe index (conditional complexity)

    private void buildCollationMapping() {
        Map<Integer, String> customCollationIndexToCollationName = null;
        Map<String, Integer> customCollationNameToCollationIndex = null;
        Map<Integer, String> customCollationIndexToCharsetName = null;
        Map<String, Integer> customCharsetNameToMblen = null;
        Map<String, String> customCharsetNameToJavaEncoding = new HashMap<>();
        Map<String, String> customJavaEncodingUcToCharsetName = new HashMap<>();
        Map<String, Integer> customCharsetNameToCollationIndex = new HashMap<>();
        Set<String> customMultibyteEncodings = new HashSet<>();

        String databaseURL = this.session.getHostInfo().getDatabaseUrl();

        if (this.cacheServerConfiguration.getValue()) {
            synchronized (customCollationIndexToCharsetNameByUrl) {
                customCollationIndexToCollationName = customCollationIndexToCollationNameByUrl.get(databaseURL);
                customCollationNameToCollationIndex = customCollationNameToCollationIndexByUrl.get(databaseURL);
                customCollationIndexToCharsetName = customCollationIndexToCharsetNameByUrl.get(databaseURL);
                customCharsetNameToMblen = customCharsetNameToMblenByUrl.get(databaseURL);
                customCharsetNameToJavaEncoding = customCharsetNameToJavaEncodingByUrl.get(databaseURL);
                customJavaEncodingUcToCharsetName = customJavaEncodingUcToCharsetNameByUrl.get(databaseURL);
                customCharsetNameToCollationIndex = customCharsetNameToCollationIndexByUrl.get(databaseURL);
                customMultibyteEncodings = customMultibyteEncodingsByUrl.get(databaseURL);
            }
        }

        if (customCollationIndexToCharsetName == null && this.session.getPropertySet().getBooleanProperty(PropertyKey.detectCustomCollations).getValue()) {
            TelemetrySpan span = this.session.getTelemetryHandler().startSpan(TelemetrySpanName.LOAD_COLLATIONS);
            try (TelemetryScope scope = span.makeCurrent()) {
                span.setAttribute(TelemetryAttribute.DB_NAME, () -> this.session.getHostInfo().getDatabase());
                span.setAttribute(TelemetryAttribute.DB_OPERATION, TelemetryAttribute.OPERATION_SELECT);
                span.setAttribute(TelemetryAttribute.DB_STATEMENT, TelemetryAttribute.OPERATION_SELECT + TelemetryAttribute.STATEMENT_SUFFIX);
                span.setAttribute(TelemetryAttribute.DB_SYSTEM, TelemetryAttribute.DB_SYSTEM_DEFAULT);
                span.setAttribute(TelemetryAttribute.DB_USER, () -> this.session.getHostInfo().getUser());
                span.setAttribute(TelemetryAttribute.THREAD_ID, () -> Thread.currentThread().getId());
                span.setAttribute(TelemetryAttribute.THREAD_NAME, () -> Thread.currentThread().getName());

                customCollationIndexToCollationName = new HashMap<>();
                customCollationNameToCollationIndex = new HashMap<>();
                customCollationIndexToCharsetName = new HashMap<>();
                customCharsetNameToMblen = new HashMap<>();
                customCharsetNameToJavaEncoding = new HashMap<>();
                customJavaEncodingUcToCharsetName = new HashMap<>();
                customCharsetNameToCollationIndex = new HashMap<>();
                customMultibyteEncodings = new HashSet<>();

                String customCharsetMapping = this.session.getPropertySet().getStringProperty(PropertyKey.customCharsetMapping).getValue();
                if (customCharsetMapping != null) {
                    String[] pairs = customCharsetMapping.split(",");
                    for (String pair : pairs) {
                        int keyEnd = pair.indexOf(":");
                        if (keyEnd > 0 && keyEnd + 1 < pair.length()) {
                            String charset = pair.substring(0, keyEnd);
                            String encoding = pair.substring(keyEnd + 1);
                            customCharsetNameToJavaEncoding.put(charset, encoding);
                            customJavaEncodingUcToCharsetName.put(encoding.toUpperCase(Locale.ENGLISH), charset);
                        }
                    }
                }

                ValueFactory<Integer> ivf = new IntegerValueFactory(this.session.getPropertySet());

                try {
                    NativePacketPayload resultPacket = this.session.getProtocol().sendCommand(getCommandBuilder().buildComQuery(null, this.session,
                            "SELECT c.COLLATION_NAME, c.CHARACTER_SET_NAME, c.ID, cs.MAXLEN, c.IS_DEFAULT='Yes' from INFORMATION_SCHEMA.COLLATIONS AS c LEFT JOIN"
                                    + " INFORMATION_SCHEMA.CHARACTER_SETS AS cs ON cs.CHARACTER_SET_NAME=c.CHARACTER_SET_NAME"),
                            false, 0);
                    Resultset rs = this.session.getProtocol().readAllResults(-1, false, resultPacket, false, null,
                            new ResultsetFactory(Type.FORWARD_ONLY, null));
                    ValueFactory<String> svf = new StringValueFactory(this.session.getPropertySet());
                    Row r;
                    while ((r = rs.getRows().next()) != null) {
                        String collationName = r.getValue(0, svf);
                        String charsetName = r.getValue(1, svf);
                        int collationIndex = ((Number) r.getValue(2, ivf)).intValue();
                        int maxlen = ((Number) r.getValue(3, ivf)).intValue();
                        boolean isDefault = ((Number) r.getValue(4, ivf)).intValue() > 0;

                        if (collationIndex >= MAP_SIZE //
                                || collationIndex != getStaticCollationIndexForCollationName(collationName)
                                || !charsetName.equals(getStaticMysqlCharsetNameForCollationIndex(collationIndex))) {
                            customCollationIndexToCollationName.put(collationIndex, collationName);
                            customCollationNameToCollationIndex.put(collationName, collationIndex);
                            customCollationIndexToCharsetName.put(collationIndex, charsetName);
                            if (isDefault || !customCharsetNameToCollationIndex.containsKey(charsetName)
                                    && CharsetMapping.getStaticCollationIndexForMysqlCharsetName(charsetName) == 0) {
                                customCharsetNameToCollationIndex.put(charsetName, collationIndex);
                            }
                        }
                        // if no static map for charsetName adding to custom map
                        if (getStaticMysqlCharsetByName(charsetName) == null) {
                            customCharsetNameToMblen.put(charsetName, maxlen);
                            if (maxlen > 1) {
                                String enc = customCharsetNameToJavaEncoding.get(charsetName);
                                if (enc != null) {
                                    customMultibyteEncodings.add(enc.toUpperCase(Locale.ENGLISH));
                                }
                            }
                        }

                    }
                } catch (IOException e) {
                    throw ExceptionFactory.createException(e.getMessage(), e, this.session.getExceptionInterceptor());
                }

                if (this.cacheServerConfiguration.getValue()) {
                    synchronized (customCollationIndexToCharsetNameByUrl) {
                        customCollationIndexToCollationNameByUrl.put(databaseURL, Collections.unmodifiableMap(customCollationIndexToCollationName));
                        customCollationNameToCollationIndexByUrl.put(databaseURL, Collections.unmodifiableMap(customCollationNameToCollationIndex));
                        customCollationIndexToCharsetNameByUrl.put(databaseURL, Collections.unmodifiableMap(customCollationIndexToCharsetName));
                        customCharsetNameToMblenByUrl.put(databaseURL, Collections.unmodifiableMap(customCharsetNameToMblen));
                        customCharsetNameToJavaEncodingByUrl.put(databaseURL, Collections.unmodifiableMap(customCharsetNameToJavaEncoding));
                        customJavaEncodingUcToCharsetNameByUrl.put(databaseURL, Collections.unmodifiableMap(customJavaEncodingUcToCharsetName));
                        customCharsetNameToCollationIndexByUrl.put(databaseURL, Collections.unmodifiableMap(customCharsetNameToCollationIndex));
                        customMultibyteEncodingsByUrl.put(databaseURL, Collections.unmodifiableSet(customMultibyteEncodings));
                    }
                }
            } catch (Throwable t) {
                span.setError(t);
                throw t;
            } finally {
                span.end();
            }
        }

        if (customCollationIndexToCharsetName != null) {
            this.collationIndexToCollationName = customCollationIndexToCollationName;
            this.collationNameToCollationIndex = customCollationNameToCollationIndex;
            this.collationIndexToCharsetName = customCollationIndexToCharsetName;
            this.charsetNameToMblen = customCharsetNameToMblen;
            this.charsetNameToJavaEncoding = customCharsetNameToJavaEncoding;
            this.javaEncodingUcToCharsetName = customJavaEncodingUcToCharsetName;
            this.charsetNameToCollationIndex = customCharsetNameToCollationIndex;
            this.multibyteEncodings = customMultibyteEncodings;
        }
    }