/**
* Replaces all the occurrences of variables with their matching values from the resolver using
* the given source builder as a template. The builder is not altered by this method.
*
* @param source the builder to use as a template, not changed, null returns null
* @return the result of the replace operation
*/
public String replace(final StrBuilder source) {
if (source == null) {
return null;
}
final StrBuilder buf = new StrBuilder(source.length()).append(source);
substitute(buf, 0, buf.length());
return buf.toString();
}
/**
* Recursive handler for multiple levels of interpolation. This is the main interpolation method,
* which resolves the values of all variable references contained in the passed in text.
*
* @param buf the string builder to substitute into, not null
* @param offset the start offset within the builder, must be valid
* @param length the length within the builder to be processed, must be valid
* @param priorVariables the stack keeping track of the replaced variables, may be null
* @return the length change that occurs, unless priorVariables is null when the int represents a
* boolean flag as to whether any change occurred.
*/
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 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
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
&& (endMatchLen = pfxMatcher.isMatch(chars, pos, offset, bufEnd)) != 0) {
// found a nested variable start
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 ((valueDelimiterMatchLen = valueDelimMatcher.isMatch(varNameExprChars, i))
!= 0) {
varName = varNameExpr.substring(0, i);
varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen);
break;
}
}
}
// on the first call initialize priorVariables
if (priorVariables == null) {
priorVariables = new ArrayList<String>();
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) {
// recursive replace
final int varLen = varValue.length();
buf.replace(startPos, endPos, varValue);
altered = true;
int 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;
}
/**
* Replaces all the occurrences of variables within the given source builder with their matching
* values from the resolver.
*
* @param source the builder to replace in, updated, null returns zero
* @return true if altered
*/
public boolean replaceIn(final StrBuilder source) {
if (source == null) {
return false;
}
return substitute(source, 0, source.length());
}
