public static StringBuffer stringSubstitution()

in src/main/java/org/apache/commons/exec/util/StringUtils.java [140:220]
59 lines of code
19 McCabe index (conditional complexity)

    public static StringBuffer stringSubstitution(final String argStr, final Map<? super String, ?> vars, final boolean isLenient) {

        final StringBuffer argBuf = new StringBuffer();

        if (argStr == null || argStr.isEmpty()) {
            return argBuf;
        }

        if (vars == null || vars.isEmpty()) {
            return argBuf.append(argStr);
        }

        final int argStrLength = argStr.length();

        for (int cIdx = 0; cIdx < argStrLength;) {

            char ch = argStr.charAt(cIdx);
            char del = ' ';

            switch (ch) {

            case '$':
                final StringBuilder nameBuf = new StringBuilder();
                del = argStr.charAt(cIdx + 1);
                if (del == '{') {
                    cIdx++;

                    for (++cIdx; cIdx < argStr.length(); ++cIdx) {
                        ch = argStr.charAt(cIdx);
                        if (ch != '_' && ch != '.' && ch != '-' && ch != '+' && !Character.isLetterOrDigit(ch)) {
                            break;
                        }
                        nameBuf.append(ch);
                    }

                    if (nameBuf.length() >= 0) {

                        String value;
                        final Object temp = vars.get(nameBuf.toString());

                        if (temp instanceof File) {
                            // for a file we have to fix the separator chars to allow
                            // cross-platform compatibility
                            value = fixFileSeparatorChar(((File) temp).getAbsolutePath());
                        } else {
                            value = Objects.toString(temp, null);
                        }

                        if (value != null) {
                            argBuf.append(value);
                        } else {
                            if (!isLenient) {
                                // complain that no variable was found
                                throw new IllegalArgumentException("No value found for : " + nameBuf);
                            }
                            // just append the unresolved variable declaration
                            argBuf.append("${").append(nameBuf.toString()).append("}");
                        }

                        del = argStr.charAt(cIdx);

                        if (del != '}') {
                            throw new IllegalArgumentException("Delimiter not found for : " + nameBuf);
                        }
                    }
                } else {
                    argBuf.append(ch);
                }
                cIdx++;

                break;

            default:
                argBuf.append(ch);
                ++cIdx;
                break;
            }
        }

        return argBuf;
    }