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/*-
* ============LICENSE_START=======================================================
* openECOMP : SDN-C
* ================================================================================
* Copyright (C) 2017 AT&T Intellectual Property. All rights
* reserved.
* ================================================================================
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ============LICENSE_END=========================================================
*/
package org.openecomp.sdnc.util.expr;
import java.util.Map;
public class ExpressionEvaluator {
public static long evalLong(String expr, Map<String, Object> vars) {
return (long) evalFloat(expr, vars);
}
public static float evalFloat(String expr, Map<String, Object> vars) {
expr = expr.trim();
int sl = expr.length();
if (sl == 0)
throw new IllegalArgumentException("Cannot interpret empty string.");
// Remove parentheses if any
if (expr.charAt(0) == '(' && expr.charAt(sl - 1) == ')')
return evalFloat(expr.substring(1, sl - 1), vars);
// Look for operators in the order of least priority
String[] sss = findOperator(expr, "-", true);
if (sss != null)
return evalFloat(sss[0], vars) - evalFloat(sss[1], vars);
sss = findOperator(expr, "+", true);
if (sss != null)
return evalFloat(sss[0], vars) + evalFloat(sss[1], vars);
sss = findOperator(expr, "/", true);
if (sss != null)
return evalFloat(sss[0], vars) / evalFloat(sss[1], vars);
sss = findOperator(expr, "*", true);
if (sss != null)
return evalFloat(sss[0], vars) * evalFloat(sss[1], vars);
// Check if expr is a number
try {
return Float.valueOf(expr);
} catch (Exception e) {
}
// Must be a variable
Object v = vars.get(expr);
if (v != null) {
if (v instanceof Float)
return (Float) v;
if (v instanceof Long)
return (Long) v;
if (v instanceof Integer)
return (Integer) v;
}
return 0;
}
public static boolean evalBoolean(String expr, Map<String, Object> vars) {
expr = expr.trim();
int sl = expr.length();
if (sl == 0)
throw new IllegalArgumentException("Cannot interpret empty string.");
if (expr.equalsIgnoreCase("true"))
return true;
if (expr.equalsIgnoreCase("false"))
return false;
// Remove parentheses if any
if (expr.charAt(0) == '(' && expr.charAt(sl - 1) == ')')
return evalBoolean(expr.substring(1, sl - 1), vars);
// Look for operators in the order of least priority
String[] sss = findOperator(expr, "or", true);
if (sss != null)
return evalBoolean(sss[0], vars) || evalBoolean(sss[1], vars);
sss = findOperator(expr, "and", true);
if (sss != null)
return evalBoolean(sss[0], vars) && evalBoolean(sss[1], vars);
sss = findOperator(expr, "not", true);
if (sss != null)
return !evalBoolean(sss[1], vars);
sss = findOperator(expr, "!=", false);
if (sss == null)
sss = findOperator(expr, "<>", false);
if (sss != null)
return evalLong(sss[0], vars) != evalLong(sss[1], vars);
sss = findOperator(expr, "==", false);
if (sss == null)
sss = findOperator(expr, "=", false);
if (sss != null)
return evalLong(sss[0], vars) == evalLong(sss[1], vars);
sss = findOperator(expr, ">=", false);
if (sss != null)
return evalLong(sss[0], vars) >= evalLong(sss[1], vars);
sss = findOperator(expr, ">", false);
if (sss != null)
return evalLong(sss[0], vars) > evalLong(sss[1], vars);
sss = findOperator(expr, "<=", false);
if (sss != null)
return evalLong(sss[0], vars) <= evalLong(sss[1], vars);
sss = findOperator(expr, "<", false);
if (sss != null)
return evalLong(sss[0], vars) < evalLong(sss[1], vars);
throw new IllegalArgumentException("Cannot interpret '" + expr + "': Invalid expression.");
}
private static String[] findOperator(String s, String op, boolean delimiterRequired) {
int opl = op.length();
int sl = s.length();
String delimiters = " \0\t\r\n()";
int pcount = 0, qcount = 0;
for (int i = 0; i < sl; i++) {
char c = s.charAt(i);
if (c == '(' && qcount == 0)
pcount++;
else if (c == ')' && qcount == 0) {
pcount--;
if (pcount < 0)
throw new IllegalArgumentException("Cannot interpret '" + s + "': Parentheses do not match.");
} else if (c == '\'')
qcount = (qcount + 1) % 2;
else if (i <= sl - opl && pcount == 0 && qcount == 0) {
String ss = s.substring(i, i + opl);
if (ss.equalsIgnoreCase(op)) {
boolean found = true;
if (delimiterRequired) {
// Check for delimiter before and after to make sure it is not part of another word
char chbefore = '\0';
if (i > 0)
chbefore = s.charAt(i - 1);
char chafter = '\0';
if (i < sl - opl)
chafter = s.charAt(i + opl);
found = delimiters.indexOf(chbefore) >= 0 && delimiters.indexOf(chafter) >= 0;
}
if (found) {
// We've found the operator, split the string
String[] sss = new String[2];
sss[0] = s.substring(0, i);
sss[1] = s.substring(i + opl);
return sss;
}
}
}
}
if (pcount > 0)
throw new IllegalArgumentException("Cannot interpret '" + s + "': Parentheses do not match.");
if (qcount > 0)
throw new IllegalArgumentException("Cannot interpret '" + s + "': No closing '.");
return null;
}
private static Object parseObject(String s) {
s = s.trim();
int sl = s.length();
if (sl == 0)
throw new IllegalArgumentException("Cannot interpret empty string.");
if (s.equalsIgnoreCase("null"))
return null;
if (s.charAt(0) == '\'') {
if (sl < 2 || s.charAt(sl - 1) != '\'')
throw new IllegalArgumentException("Cannot interpret '" + s + "': No closing '.");
return s.substring(1, sl - 1);
}
// Not in quotes - must be a number
try {
return Long.valueOf(s);
} catch (Exception e) {
}
try {
return Double.valueOf(s);
} catch (Exception e) {
throw new IllegalArgumentException("Cannot interpret '" + s + "': Invalid number.");
}
}
}
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