下列程序中用到的所有抽象数据类型的定义？拜托拜托
public String toPostFix(String infix) {
char[] ch = infix.trim().toCharArray();
LinkedList<OperatorsEnum> stack = new LinkedList<OperatorsEnum>();
StringBuilder sb = new StringBuilder();
OperatorsEnum op = null;
for (int i = 0; i < ch.length; i++) {
if ((op = isOperator(ch[i])) == null) {
sb.append(ch[i]);
} else
{ if (op.equals(OperatorsEnum.RIGHT_BRACKET)) {
while (!stack.peek().equals(OperatorsEnum.LEFT_BRACKET)) {
sb.append(stack.pop());
} stack.pop();
} else {while (stack.size() > 0 && stack.peek().prior >= op.prior
&& !stack.peek().equals(OperatorsEnum.LEFT_BRACKET)) {
sb.append(stack.pop());
}
stack.push(op);
} } }
while (stack.size() > 0) { sb.append(stack.pop()); } return sb.toString(); } }类似于图片那种