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com.firefly.template.support.RPNUtils Maven / Gradle / Ivy
package com.firefly.template.support;
import java.util.Arrays;
import java.util.Deque;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import com.firefly.template.exception.ExpressionError;
import com.firefly.utils.VerifyUtils;
public class RPNUtils {
private static final Set CONDITIONAL_OPERATOR = new HashSet(Arrays.asList("==", "!=", ">", "<", ">=", "<="));
private static final Set ARITHMETIC_OR_LOGICAL_OPERATOR = new HashSet(Arrays.asList("&", "|"));
private static final Set LOGICAL_OPERATOR = new HashSet(Arrays.asList("&&", "||"));
private static final Set ASSIGNMENT_OPERATOR = new HashSet(Arrays.asList("=", "+=", "-=", "*=", "/=", "%=", "^=", "&=", "|=", "<<=", ">>=", ">>>="));
/**
* This method parses the expression and creates Reverse Polish notation
* symbol priority：
* 10: "*", "/", "%"
* 9: "+", "-"
* 8: ">>", ">>>", "<<"
* 7: ">", "<", ">=", "<="
* 6: "==", "!="
* 5: "&"
* 4: "|"
* 3: "^"
* 2: "&&"
* 1: "||"
* 0: "=", "+=", "-=", "*=", "/=", "%=", "^=", "&=", "|=", "<<=", ">>=", ">>>=" //0
* @param text the infix notation
* @return A list has many tokens and the sequence of postfix notation
*/
public static List getReversePolishNotation(String text) {
String content = preprocessing(text);
StringBuilder pre = new StringBuilder();
Deque symbolDeque = new LinkedList();
List list = new LinkedList();
char c, n, n1, n2;
for (int i = 0; i < content.length(); i++) {
switch (content.charAt(i)) {
case '\'':
case '"':
int next = content.indexOf(content.charAt(i), i + 1);
while(content.charAt(next - 1) == '\\')
next = content.indexOf(content.charAt(i), next + 1);
pre.append(content.substring(i, next + 1));
i += next - i;
break;
case '(':
pre.delete(0, pre.length());
Fragment f0 = new Fragment();
f0.priority = -1000;
f0.value = "(";
symbolDeque.push(f0);
break;
case '*':
case '/':
case '%':
n = content.charAt(i + 1);
if(n == '=') { // *= /= %=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 0, symbolDeque, list);
i++;
break;
}
// * / %
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)), 10, symbolDeque, list);
break;
case '+':
case '-':
n = content.charAt(i + 1);
if(n == '=') { // += -=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 0, symbolDeque, list);
i++;
break;
}
if(n == content.charAt(i)) {
pre.append(content.charAt(i)).append(content.charAt(i + 1));
i++;
break;
}
// 正负号判断
boolean s = false;
String left0 = "*/%+-><=&|(^";
if(i == 0) {
s = true;
} else {
for(int j = i - 1; j >= 0; j--) {
char ch = content.charAt(j);
if(!Character.isWhitespace(ch) ) {
if(left0.indexOf(ch) >= 0) {
int _n = j - 1;
s = _n < 0 || !(ch == '+' && content.charAt(_n) == '+' || ch == '-' && content.charAt(_n) == '-');
}
break;
}
}
}
// + -
if(s) {
pre.append(content.charAt(i));
} else {
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)), 9, symbolDeque, list);
}
break;
case '>':
case '<':
c = content.charAt(i);
n = content.charAt(i + 1);
if(c == n) {
if(i + 2 < content.length()) {
n1 = content.charAt(i + 2);
if(n1 == '=') { // <<= >>=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + content.charAt(i + 1) + "=", 0, symbolDeque, list);
i += 2;
break;
}
}
// << >>
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + content.charAt(i + 1), 8, symbolDeque, list);
i++;
break;
}
if(i + 2 < content.length()) {
n1 = content.charAt(i + 2);
if(c == '>' && n == '>' && n1 == '>') {
n2 = content.charAt(i + 3);
if(i + 3 < content.length()) {
if(n2 == '=') { // >>>=
outValue(pre, list);
outSymbol(">>>=", 0, symbolDeque, list);
i += 3;
break;
}
}
// >>>
outValue(pre, list);
outSymbol(">>>", 8, symbolDeque, list);
i += 2;
break;
}
}
if(n == '=') { // <= >=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 7, symbolDeque, list);
i++;
break;
}
// < >
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)), 7, symbolDeque, list);
break;
case '=':
n = content.charAt(i + 1);
if(n == '=') { // ==
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 6, symbolDeque, list);
i++;
break;
}
// =
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)), 0, symbolDeque, list);
break;
case '!':
n = content.charAt(i + 1);
if(n == '=') { // !=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 6, symbolDeque, list);
i++;
break;
}
pre.append('!');
break;
case '&':
n = content.charAt(i + 1);
if(n == '&') { // &&
outValue(pre, list);
outSymbol("&&", 2, symbolDeque, list);
i++;
break;
}
if(n == '=') { // &=
outValue(pre, list);
outSymbol("&=", 0, symbolDeque, list);
i++;
break;
}
// &
outValue(pre, list);
outSymbol("&", 5, symbolDeque, list);
break;
case '|':
n = content.charAt(i + 1);
if(n == '|') { // ||
outValue(pre, list);
outSymbol("||", 1, symbolDeque, list);
i++;
break;
}
if(n == '=') { // |=
outValue(pre, list);
outSymbol("|=", 0, symbolDeque, list);
i++;
break;
}
// |
outValue(pre, list);
outSymbol("|", 4, symbolDeque, list);
break;
case '^':
n = content.charAt(i + 1);
if(n == '=') {// ^=
outValue(pre, list);
outSymbol(String.valueOf(content.charAt(i)) + "=", 0, symbolDeque, list);
i++;
break;
}
// ^
outValue(pre, list);
outSymbol("^", 3, symbolDeque, list);
break;
case ')':
outValue(pre, list);
outSymbol(")", -1000, symbolDeque, list);
break;
default:
pre.append(content.charAt(i));
break;
}
}
outValue(pre, list);
while(!symbolDeque.isEmpty())
list.add(symbolDeque.pop());
return list;
}
private static String preprocessing(String content) {
StringBuilder ret = new StringBuilder();
if(preprocessing0(content, ret))
return ret.toString();
else
return preprocessing(ret.toString());
}
private static boolean preprocessing0(String content, StringBuilder ret) {
boolean t = true;
StringBuilder pre = new StringBuilder();
int c = 0;
int start = 0;
for (int i = 0; i < content.length(); i++) {
char ch = content.charAt(i);
switch (ch) {
case '!':
case '+':
case '-':
boolean l = false;
boolean r = false;
String left0 = "*/%+-><=&|(^";
if(i == 0 || ch == '!') {
l = true;
} else {
for(int j = i - 1; j >= 0; j--) {
char c0 = content.charAt(j);
if(!Character.isWhitespace(c0) ) {
if(left0.indexOf(c0) >= 0) {
int _n = j - 1;
l = _n < 0 || !(c0 == '+' && content.charAt(_n) == '+' || c0 == '-' && content.charAt(_n) == '-');
}
break;
}
}
}
if(l) {
for (int j = i + 1; j < content.length(); j++) {
char c0 = content.charAt(j);
if(!Character.isWhitespace(c0)) {
if(c0 == '(') {
start = j + 1;
r = true;
pre.append(c0);
}
break;
}
}
}
if(l && r) {
t = false;
c += 1;
while(c != 0) {
char c0 = content.charAt(start++);
if(c0 == '(')
c++;
else if(c0 == ')')
c--;
pre.append(c0);
}
if(ch == '!')
ret.append("(").append(pre).append(" == false) ");
else
ret.append("(0 ").append(ch).append(' ').append(pre).append(") ");
pre.delete(0, pre.length());
i = start;
} else
ret.append(ch);
break;
default:
ret.append(ch);
break;
}
}
return t;
}
/**
* remove redundant symbols, such as +, -
* @param v
* @return
*/
private static String getSimpleValue(String v) {
int left = 0;
boolean n = false;
for (int i = 0; i < v.length(); i++) {
char ch = v.charAt(i);
if(ch == '-')
n = true;
if(ch != '+' && ch != '-' && !Character.isWhitespace(ch)) {
left = i;
break;
}
}
String s = v.substring(left);
return n ? "-" + s : s;
}
private static boolean isString(String v) {
int start = v.charAt(0);
int end = v.charAt(v.length() - 1);
return (start == '"' && end == '"') || (start == '\'' && end == '\'');
}
private static boolean isBoolean(String v) {
int start = v.charAt(0) == '!' ? 1 : 0;
return v.substring(start).trim().equals("true") || v.substring(start).trim().equals("false");
}
private static boolean isVariable(String v) {
int start = v.indexOf("${");
int end = v.indexOf('}');
return start >= 0 && start < end;
}
private static void outValue(StringBuilder pre, List list) {
String v = pre.toString().trim();
if(v.length() > 0) {
Fragment f= new Fragment();
f.priority = -200;
f.value = getSimpleValue(v);
if(isVariable(f.value)) {
f.type = Type.VARIABLE;
} else if(isBoolean(f.value)) {
f.type = Type.BOOLEAN;
} else if(isString(f.value)) {
f.type = Type.STRING;
f.value = "\"" + f.value.substring(1, f.value.length() - 1) + "\"";
} else if(VerifyUtils.isFloat(f.value)) {
f.type = Type.FLOAT;
char end = f.value.charAt(f.value.length() - 1);
if(end == 'f' || end == 'F')
f.value = f.value.substring(0, f.value.length() - 1);
} else if(VerifyUtils.isDouble(f.value)) {
f.type = Type.DOUBLE;
} else if(VerifyUtils.isInteger(f.value)) {
f.type = Type.INTEGER;
} else if(VerifyUtils.isLong(f.value)) {
f.type = Type.LONG;
char end = f.value.charAt(f.value.length() - 1);
if(end == 'l' || end == 'L')
f.value = f.value.substring(0, f.value.length() - 1);
} else if(f.value.equals("null")) {
f.type = Type.NULL;
} else
throw new ExpressionError("Can not determine the type: " + f.value);
list.add(f);
}
pre.delete(0, pre.length());
}
private static void outSymbol(String value, int priority, Deque symbolDeque, List list) {
Fragment f = new Fragment();
f.value = value;
f.priority = priority;
if(ARITHMETIC_OR_LOGICAL_OPERATOR.contains(value)) {
f.type = Type.ARITHMETIC_OR_LOGICAL_OPERATOR;
} else if(LOGICAL_OPERATOR.contains(value)) {
f.type = Type.LOGICAL_OPERATOR;
} else if(ASSIGNMENT_OPERATOR.contains(value)) {
f.type = Type.ASSIGNMENT_OPERATOR;
} else if(CONDITIONAL_OPERATOR.contains(value)) {
f.type = Type.CONDITIONAL_OPERATOR;
} else
f.type = Type.ARITHMETIC_OPERATOR;
if(f.value.equals(")")) {
for(Fragment top = null; !symbolDeque.isEmpty()
&& !(top = symbolDeque.pop()).value.equals("("); )
list.add(top);
} else {
for(Fragment top = null; !symbolDeque.isEmpty()
&& (top = symbolDeque.peek()).priority >= f.priority; ) {
list.add(top);
symbolDeque.pop();
}
symbolDeque.push(f);
}
}
public static class Fragment {
public int priority;
public String value;
public Type type;
@Override
public String toString() {
return value;
}
}
public static enum Type {
VARIABLE,
INTEGER,
LONG,
FLOAT,
DOUBLE,
BOOLEAN,
STRING,
NULL,
ARITHMETIC_OPERATOR,
LOGICAL_OPERATOR,
ASSIGNMENT_OPERATOR,
ARITHMETIC_OR_LOGICAL_OPERATOR,
CONDITIONAL_OPERATOR
}
}
