public RealMatrix parse()

in commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/linear/RealMatrixFormat.java [301:390]
74 lines of code
18 McCabe index (conditional complexity)

    public RealMatrix parse(String source, ParsePosition pos) {
        int initialIndex = pos.getIndex();

        final String trimmedPrefix = prefix.trim();
        final String trimmedSuffix = suffix.trim();
        final String trimmedRowPrefix = rowPrefix.trim();
        final String trimmedRowSuffix = rowSuffix.trim();
        final String trimmedColumnSeparator = columnSeparator.trim();
        final String trimmedRowSeparator = rowSeparator.trim();

        // parse prefix
        CompositeFormat.parseAndIgnoreWhitespace(source, pos);
        if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) {
            return null;
        }

        // parse components
        List<List<Number>> matrix = new ArrayList<>();
        List<Number> rowComponents = new ArrayList<>();
        for (boolean loop = true; loop;){

            if (!rowComponents.isEmpty()) {
                CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                if (!CompositeFormat.parseFixedstring(source, trimmedColumnSeparator, pos)) {
                    if (!trimmedRowSuffix.isEmpty() &&
                        !CompositeFormat.parseFixedstring(source, trimmedRowSuffix, pos)) {
                        return null;
                    }
                    CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                    if (CompositeFormat.parseFixedstring(source, trimmedRowSeparator, pos)) {
                        matrix.add(rowComponents);
                        rowComponents = new ArrayList<>();
                        continue;
                    }
                    loop = false;
                }
            } else {
                CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                if (!trimmedRowPrefix.isEmpty() &&
                    !CompositeFormat.parseFixedstring(source, trimmedRowPrefix, pos)) {
                    return null;
                }
            }

            if (loop) {
                CompositeFormat.parseAndIgnoreWhitespace(source, pos);
                Number component = CompositeFormat.parseNumber(source, format, pos);
                if (component != null) {
                    rowComponents.add(component);
                } else {
                    if (rowComponents.isEmpty()) {
                        loop = false;
                    } else {
                        // invalid component
                        // set index back to initial, error index should already be set
                        pos.setIndex(initialIndex);
                        return null;
                    }
                }
            }
        }

        if (!rowComponents.isEmpty()) {
            matrix.add(rowComponents);
        }

        // parse suffix
        CompositeFormat.parseAndIgnoreWhitespace(source, pos);
        if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) {
            return null;
        }

        // do not allow an empty matrix
        if (matrix.isEmpty()) {
            pos.setIndex(initialIndex);
            return null;
        }

        // build vector
        double[][] data = new double[matrix.size()][];
        int row = 0;
        for (List<Number> rowList : matrix) {
            data[row] = new double[rowList.size()];
            for (int i = 0; i < rowList.size(); i++) {
                data[row][i] = rowList.get(i).doubleValue();
            }
            row++;
        }
        return MatrixUtils.createRealMatrix(data);
    }