* "ghi" => "foo"* * @param props * The table of variables to use when substituting. * * @param expr * The property name, prossibly containing substitutions. * * @param defaultValue * The value to use if the top-level substitution does not * exist. May be
* "deffoojkl" => "baz"
* "abcbazmno" => "garply"
* * getProperty("ghi") => "foo"
* getProperty("def${ghi}jkl") => "baz"
* getProperty("abc${def${ghi}jkl}mno") => "garply"
*
null.
*/
public static String
getProperty(Properties props, String expr, String defaultValue) {
return props.getProperty(subst(props, expr), defaultValue);
}
/**
* Allow a tag attribute value to contain the value of another
* property, permitting nested variable substitution in attribute
* values. To escape ${XXX}, use \${XXX}.
* * The sequence "\X" is identical to "X", except when "X" is one of: *
*
* "ghi" = "foo"* * @param props The table of variables to substitute. * If this is a Properties object, then the * getProperty() method is used instead of the * Dictionary class get() method. * @param str The expression containing the substitutions. * Embedded property names, bracketted by "${" and "}" * are looked up in the props table and replaced with * their value. Nested substitutions are allowed. * * @return The substituted string. If a variable is not * found in the table, the empty string is used. */ public static String subst(Dictionary props, String str) { return subst(props, str, false); } /** * Allow a tag attribute value to contain the value of another * property, permitting nested variable substitution in attribute * values. To escape ${XXX}, use \${XXX}. * See {@link #subst(Dictionary props, String str) above}. *
* "deffoojkl" = "baz"
* "abcbazmno" = "garply"
* * subst("ghi") = "ghi"
* subst("def${ghi}jkl") = "deffoojkl"
* subst("def\${ghi}jkl") = "def${ghi}jkl"
* subst("abc${def${ghi}jkl}mno") = "abcbazmno"
* subst("${abc${def${ghi}jkl}mno}") = "garply"
*
* if noEsc is true, then
* The sequence "\X" is identical to "\X" for all X except X=$.
*/
public static String
subst(Dictionary props, String str, boolean noEsc) {
if (str == null) {
return null;
}
return subst(props, new Chars(str), noEsc);
}
private static String subst(Dictionary dict, Chars chars, boolean esc) {
StringBuffer sb = new StringBuffer();
char c;
char save;
String result;
String value;
loop: while (true) {
c = chars.get();
switch (c) {
case Chars.NUL:
break loop;
case '$':
c = chars.get();
switch (c) {
case Chars.NUL:
sb.append('$');
break loop;
case '{':
save = chars.setend('}');
result = subst(dict, chars, esc);
chars.setend(save);
value = getProperty(dict, result);
sb.append(value);
break;
default:
chars.pushback();
sb.append('$');
break;
}
break;
case '\\':
c = chars.getraw();
if (c == Chars.NUL) {
sb.append('\\');
break loop;
}
if (esc) { // only \$ is special
switch (c) {
case '$':
break;
default:
chars.pushback();
c = '\\';
break;
}
} else { // other stuff is special too
switch (c) {
case 'a':
c = '&';
break;
case 'g':
c = '>';
break;
case 'l':
c = '<';
break;
case 'q':
c = '"';
break;
case 's':
c = ' ';
break;
case 'v':
c = '\'';
break;
case 'n':
c = '\n';
break;
case 'r':
c = '\r';
break;
case 't':
c = '\t';
break;
default:
break;
}
}
sb.append(c);
break;
default:
sb.append(c);
break;
}
}
return sb.toString();
}
private static String getProperty(Dictionary dict, String name) {
int hash = name.indexOf('#');
String def = "";
if (hash >= 0) {
def = name.substring(hash + 1);
name = name.substring(0, hash);
}
Object obj;
if (dict instanceof Properties) {
obj = ((Properties) dict).getProperty(name);
} else {
obj = dict.get(name);
}
String value = (obj == null) ? null : obj.toString();
if (value == null || value.length() == 0)
value = def;
return value;
}
/**
* See if a String represents a "true" boolean value, which consists of:
* "yes", "true", "on", or "1", in any case.
*/
public static boolean isTrue(String s) {
if (s != null) {
String v = s.trim().toLowerCase();
return v.equals("true") || v.equals("yes") ||
v.equals("on") || v.equals("1");
}
return false;
}
/**
* See if a String represents a "false" boolean value, which consists of:
* "no", "false", "off", or "0", in any case.
*/
public static boolean isFalse(String s) {
if (s != null) {
String v = s.trim().toLowerCase();
return v.equals("false") || v.equals("no") ||
v.equals("off") || v.equals("0");
}
return false;
}
/**
* Convert a string to an integer; use a default value if the
* conversion fails.
* @param value the value to attemp conversion of
* @param dftl The result if the value is not a valid number
* @return The integer value of "value", or "dflt" if value is NAN.
*/
public static int stringToInt(String value, int dflt) {
try {
return Integer.parseInt(value);
} catch (NumberFormatException e) {
return dflt;
}
}
/**
* Remove surrounding quotes (" or ') from a string.
*/
public static String deQuote(String str) {
int len;
if (str==null || (len=str.length()) < 2) {
return str;
}
char ch = str.charAt(0);
if (((ch == '"') || (ch == '\'')) && (str.charAt(len-1) == ch)) {
return str.substring(1, len-1);
}
return str;
}
/**
* Make an html string suitable for including as an attribute value.
* Convert '<', '>', '&', '"', and ''' to \l, \g, \a, \q and \a.
*/
public static String unsubst(String data) {
String TOKENS = "<>&\"\'\n\t";
StringTokenizer st = new StringTokenizer(data, TOKENS, true);
StringBuffer sb = new StringBuffer();
while (st.hasMoreTokens()) {
String token = st.nextToken();
if (token.length() > 0) {
sb.append(token);
} else {
switch(token.charAt(0)) {
case '<': sb.append("\\l"); break;
case '>': sb.append("\\g"); break;
case '&': sb.append("\\a"); break;
case '\"': sb.append("\\q"); break;
case '\'': sb.append("\\v"); break;
case '\n': sb.append("\\n"); break;
case '\t': sb.append("\\t"); break;
default: sb.append(token); break;
}
}
}
return sb.toString();
}
}
class Chars {
public static final char NUL = '\0';
private int i;
private char end;
private char[] chars;
Chars(String s) {
i = 0;
end = NUL;
chars = s.toCharArray();
}
char getraw() {
if (i >= chars.length)
return NUL;
return chars[i++];
}
char get() {
char c = getraw();
if (c == end)
return NUL;
return c;
}
void pushback() {
if (--i < 0)
i = 0;
}
char setend(char end) {
char save = this.end;
this.end = end;
return save;
}
}