in src/main/java/org/apache/commons/text/StrSubstitutor.java [1128:1272]
private int substitute(final StrBuilder buf, final int offset, final int length, List<String> priorVariables) {
final StrMatcher pfxMatcher = getVariablePrefixMatcher();
final StrMatcher suffMatcher = getVariableSuffixMatcher();
final char escape = getEscapeChar();
final StrMatcher valueDelimMatcher = getValueDelimiterMatcher();
final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables();
final boolean substitutionInValuesDisabled = isDisableSubstitutionInValues();
final boolean top = priorVariables == null;
boolean altered = false;
int lengthChange = 0;
char[] chars = buf.buffer;
int bufEnd = offset + length;
int pos = offset;
while (pos < bufEnd) {
final int startMatchLen = pfxMatcher.isMatch(chars, pos, offset,
bufEnd);
if (startMatchLen == 0) {
pos++;
} else {
// found variable start marker
if (pos > offset && chars[pos - 1] == escape) {
// escaped
if (preserveEscapes) {
pos++;
continue;
}
buf.deleteCharAt(pos - 1);
chars = buf.buffer; // in case buffer was altered
lengthChange--;
altered = true;
bufEnd--;
} else {
// find suffix
final int startPos = pos;
pos += startMatchLen;
int endMatchLen = 0;
int nestedVarCount = 0;
while (pos < bufEnd) {
if (substitutionInVariablesEnabled
&& pfxMatcher.isMatch(chars,
pos, offset, bufEnd) != 0) {
// found a nested variable start
endMatchLen = pfxMatcher.isMatch(chars,
pos, offset, bufEnd);
nestedVarCount++;
pos += endMatchLen;
continue;
}
endMatchLen = suffMatcher.isMatch(chars, pos, offset,
bufEnd);
if (endMatchLen == 0) {
pos++;
} else {
// found variable end marker
if (nestedVarCount == 0) {
String varNameExpr = new String(chars, startPos
+ startMatchLen, pos - startPos
- startMatchLen);
if (substitutionInVariablesEnabled) {
final StrBuilder bufName = new StrBuilder(varNameExpr);
substitute(bufName, 0, bufName.length());
varNameExpr = bufName.toString();
}
pos += endMatchLen;
final int endPos = pos;
String varName = varNameExpr;
String varDefaultValue = null;
if (valueDelimMatcher != null) {
final char[] varNameExprChars = varNameExpr.toCharArray();
int valueDelimiterMatchLen = 0;
for (int i = 0; i < varNameExprChars.length; i++) {
// if there's any nested variable when nested variable substitution disabled,
// then stop resolving name and default value.
if (!substitutionInVariablesEnabled
&& pfxMatcher.isMatch(varNameExprChars,
i,
i,
varNameExprChars.length) != 0) {
break;
}
if (valueDelimMatcher.isMatch(varNameExprChars, i) != 0) {
valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i);
varName = varNameExpr.substring(0, i);
varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen);
break;
}
}
}
// on the first call initialize priorVariables
if (priorVariables == null) {
priorVariables = new ArrayList<>();
priorVariables.add(new String(chars,
offset, length));
}
// handle cyclic substitution
checkCyclicSubstitution(varName, priorVariables);
priorVariables.add(varName);
// resolve the variable
String varValue = resolveVariable(varName, buf,
startPos, endPos);
if (varValue == null) {
varValue = varDefaultValue;
}
if (varValue != null) {
final int varLen = varValue.length();
buf.replace(startPos, endPos, varValue);
altered = true;
int change = 0;
if (!substitutionInValuesDisabled) { // recursive replace
change = substitute(buf, startPos,
varLen, priorVariables);
}
change = change
+ varLen - (endPos - startPos);
pos += change;
bufEnd += change;
lengthChange += change;
chars = buf.buffer; // in case buffer was
// altered
}
// remove variable from the cyclic stack
priorVariables
.remove(priorVariables.size() - 1);
break;
}
nestedVarCount--;
pos += endMatchLen;
}
}
}
}
}
if (top) {
return altered ? 1 : 0;
}
return lengthChange;
}