/** do some pre-computation parsing to a formula */
public static String preParse(String f, FormulaManager fm) {
// remove spaces
StringTokenizer t = new StringTokenizer(f, " ", false);
String s = "";
while (t.hasMoreTokens()) s = s + t.nextToken();
if (s.equals("")) return s;
// multi-pass pre-parse sequence
String os;
do {
os = s;
s = preParseOnce(os, fm);
} while (!s.equals(os));
return s;
}
/**
* convert an array of strings of the form "package.Class.method(Class, Class, ...)" to
* an array of Method objects
*/
public static Method[] stringsToMethods(String[] strings) {
int len = strings.length;
Method[] methods = new Method[len];
for (int j = 0; j < len; j++) {
// remove spaces
StringTokenizer t = new StringTokenizer(strings[j], " ", false);
String s = "";
while (t.hasMoreTokens()) s = s + t.nextToken();
// separate into two strings
t = new StringTokenizer(s, "(", false);
String pre = t.nextToken();
String post = t.nextToken();
// separate first string into class and method strings
t = new StringTokenizer(pre, ".", false);
String c = t.nextToken();
int count = t.countTokens();
for (int i = 0; i < count - 1; i++) c = c + "." + t.nextToken();
String m = t.nextToken();
// get argument array of strings
t = new StringTokenizer(post, ",)", false);
count = t.countTokens();
String[] a;
if (count == 0) a = null;
else a = new String[count];
int x = 0;
while (t.hasMoreTokens()) a[x++] = t.nextToken();
// convert result to Method object
Class clas = null;
try {
clas = Class.forName(c);
} catch (ClassNotFoundException exc) {
if (FormulaVar.DEBUG) {
System.out.println("ERROR: Class " + c + " does not exist!");
}
methods[j] = null;
continue;
}
Class[] param;
if (a == null) param = null;
else param = new Class[a.length];
for (int i = 0; i < count; i++) {
// hack to convert array arguments to correct form
if (a[i].endsWith("[]")) {
a[i] = "[L" + a[i].substring(0, a[i].length() - 2);
while (a[i].endsWith("[]")) {
a[i] = "[" + a[i].substring(0, a[i].length() - 2);
}
a[i] = a[i] + ";";
}
try {
param[i] = Class.forName(a[i]);
} catch (ClassNotFoundException exc) {
if (FormulaVar.DEBUG) {
System.out.println("ERROR: Class " + a[i] + " (" + i + ") does not exist!");
}
methods[j] = null;
continue;
}
}
Method method = null;
try {
method = clas.getMethod(m, param);
} catch (NoSuchMethodException exc) {
if (FormulaVar.DEBUG) {
System.out.println("ERROR: Method " + m + " does not exist!");
}
methods[j] = null;
continue;
}
methods[j] = method;
}
return methods;
}
/** used by preParse */
private static String preParseOnce(String s, FormulaManager fm) {
// convert to lower case
String l = s.toLowerCase();
// scan entire string
int len = l.length();
boolean letter = false;
String ns = "";
for (int i = 0; i < len; i++) {
if (!letter && i < len - 1 && l.substring(i, i + 2).equals("d(")) {
// convert d(x)/d(y) notation to standard derive(x, y) notation
i += 2;
int s1 = i;
for (int paren = 1; paren > 0; i++) {
// check for correct syntax
if (i >= len) return s;
char c = l.charAt(i);
if (c == '(') paren++;
if (c == ')') paren--;
}
int e1 = i - 1;
// check for correct syntax
if (i > len - 3 || !l.substring(i, i + 3).equals("/d(")) return s;
i += 3;
int s2 = i;
for (int paren = 1; paren > 0; i++) {
// check for correct syntax
if (i >= len) return s;
char c = l.charAt(i);
if (c == '(') paren++;
if (c == ')') paren--;
}
int e2 = i - 1;
ns = ns + "derive(" + s.substring(s1, e1) + "," + s.substring(s2, e2) + ")";
i--;
} else if (!letter && i < len - 4 && l.substring(i, i + 5).equals("link(")) {
// evaluate link(code) notation and replace with link variable
i += 5;
int s1 = i;
try {
while (l.charAt(i) != '(') i++;
} catch (ArrayIndexOutOfBoundsException exc) {
// incorrect syntax
return s;
}
i++;
int e1 = i - 1;
int s2 = i;
for (int paren = 2; paren > 1; i++) {
// check for correct syntax
if (i >= len) return s;
char c = l.charAt(i);
if (c == '(') paren++;
if (c == ')') paren--;
}
int e2 = i - 1;
// check for correct syntax
if (i >= len || l.charAt(i) != ')') return s;
String prestr = s.substring(s1, e1) + "(";
String str = prestr;
// parse method's arguments; determine if they are Data or RealType
String sub = s.substring(s2, e2);
StringTokenizer st = new StringTokenizer(sub, ",", false);
boolean first = true;
Vector v = new Vector();
while (st.hasMoreTokens()) {
String token = st.nextToken();
if (first) first = false;
else str = str + ",";
RealType rt = RealType.getRealTypeByName(token);
String sv = (rt == null ? "visad.Data" : "visad.RealType");
v.add(sv);
str = str + sv;
}
str = str + ")";
// obtain Method object
Method[] meths = FormulaUtil.stringsToMethods(new String[] {str});
if (meths[0] == null) {
// attempt to identify any matching methods by compressing
// some or all of the arguments into array form
int vlen = v.size();
Vector vstrs = new Vector();
for (int iv = 0; iv < vlen; iv++) {
String si = (String) v.elementAt(iv);
int lv = iv;
String sl;
while (lv < vlen) {
sl = (String) v.elementAt(lv++);
if (!sl.equals(si)) {
break;
}
str = prestr;
first = true;
for (int j = 0; j < vlen; j++) {
if (first) first = false;
else str = str + ",";
String sj = (String) v.elementAt(j);
str = str + sj;
if (iv == j) {
str = str + "[]";
j = lv - 1;
}
}
str = str + ")";
vstrs.add(str);
}
}
String[] strlist = new String[vstrs.size()];
vstrs.toArray(strlist);
meths = FormulaUtil.stringsToMethods(strlist);
int found = -1;
for (int j = 0; j < meths.length && found < 0; j++) {
if (meths[j] != null) found = j;
}
if (found >= 0) meths[0] = meths[found];
else {
// could not find a matching method
return s;
}
}
// store method object in a link variable
String link = "link" + (++linkNum);
try {
fm.setThing(link, new VMethod(meths[0]));
}
// catch any errors setting the link variable
catch (FormulaException exc) {
return s;
} catch (VisADException exc) {
return s;
} catch (RemoteException exc) {
return s;
}
ns = ns + "linkx(" + link + "," + s.substring(s2, e2) + ")";
} else if (!letter) {
int j = i;
char c = l.charAt(j++);
while (j < len && ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9'))) {
c = l.charAt(j++);
}
// check for end-of-string
if (j == len) return ns + s.substring(i, len);
if (c == '[') {
// convert x[y] notation to standard getSample(x, y) notation
int k = j;
for (int paren = 1; paren > 0; k++) {
// check for correct syntax
if (k >= len) return s;
c = l.charAt(k);
if (c == '[') paren++;
if (c == ']') paren--;
}
ns = ns + "getSample(" + s.substring(i, j - 1) + "," + s.substring(j, k - 1) + ")";
i = k - 1;
} else ns = ns + s.charAt(i);
} else {
// append character to new string
ns = ns + s.charAt(i);
}
char c = (i < len) ? l.charAt(i) : '\0';
letter = (c >= 'a' && c <= 'z');
}
return ns;
}