public static String evaluate()

in gshell-bootstrap/src/main/java/org/apache/geronimo/gshell/bootstrap/ExpressionEvaluator.java [54:105]
37 lines of code
8 McCabe index (conditional complexity)

    public static String evaluate(final String input, final Properties props) throws IllegalArgumentException {
        StringBuffer sbuf = new StringBuffer();

        int i = 0;
        int j, k;

        while (true) {
            j = input.indexOf(DELIM_START, i);
            if (j == -1) {
                // no more variables
                if (i == 0) { // this is a simple string
                    return input;
                }
                else { // add the tail string which contails no variables and return the result.
                    sbuf.append(input.substring(i, input.length()));
                    return sbuf.toString();
                }
            }
            else {
                sbuf.append(input.substring(i, j));
                k = input.indexOf(DELIM_STOP, j);

                if (k == -1) {
                    throw new IllegalArgumentException('"' + input + "\" has no closing brace. Opening brace at position " + j);
                }
                else {
                    j += DELIM_START_LEN;
                    String key = input.substring(j, k);

                    // first try in System properties
                    String replacement = getSystemProperty(key);

                    // then try props parameter
                    if (replacement == null && props != null) {
                        replacement = props.getProperty(key);
                    }

                    if (replacement != null) {
                        // Do variable substitution on the replacement string
                        // such that we can solve "Hello ${x2}" as "Hello p1"
                        // the where the properties are
                        // x1=p1
                        // x2=${x1}
                        String recursiveReplacement = evaluate(replacement, props);
                        sbuf.append(recursiveReplacement);
                    }

                    i = k + DELIM_STOP_LEN;
                }
            }
        }
    }