Added Numeric check to StringUtil

src/zutil/StringUtil.java

@@ -55,6 +55,9 @@ public class StringUtil {
         return value+" "+sizes[total];
     }
 
+    /**
+     * @return a human readable String with year/month/day/hour/min/sec/milisec delimitation.
+     */
     public static String formatTimeToString(long milisec){
         StringBuilder str = new StringBuilder();
         long tmp;
@@ -165,6 +168,7 @@ public class StringUtil {
         if( str == null || str.isEmpty() )
             return str;
         int start=0, stop=str.length();
+
         // The beginning
         for(int i=0; i<str.length() ;i++){
             char c = str.charAt(i);
@@ -173,6 +177,7 @@ public class StringUtil {
             else
                 break;
         }
+
         // The end
         for(int i=str.length()-1; i>start ;i--){
             char c = str.charAt(i);
@@ -181,9 +186,10 @@ public class StringUtil {
             else
                 break;
         }
+
         if(start >= str.length())
             return "";
-        //System.out.println("str: \""+str+"\" start: "+start+" stop: "+stop);
+
         return str.substring(start, stop);
     }
 
@@ -195,15 +201,18 @@ public class StringUtil {
     public static String trimQuotes(String str){
         if( str == null )
             return null;
+
         str = str.trim();
         if( str.length() >= 2 && str.charAt(0)=='\"' && str.charAt(str.length()-1)=='\"'){
             str = str.substring(1, str.length()-1);
         }
+
         return str;
     }
 
 
     private static ArrayList<String> SPACES = new ArrayList<>();
+
     /**
      * @return A string containing a specific amount of spaces
      */
@@ -236,6 +245,7 @@ public class StringUtil {
     public static List<String> split(String str, char delimiter){
         ArrayList<String> splitList = new ArrayList<>();
         int from = 0, to = 0;
+
         while (to >= 0) {
             to = str.indexOf(delimiter, from + 1);
             if (to < 0)
@@ -244,6 +254,51 @@ public class StringUtil {
                 splitList.add(str.substring(from, to));
             from = to;
         }
+
         return splitList;
     }
+
+    /**
+     * @return true only if the String contains correct numerical characters.
+     */
+    public static boolean isNumber(String str) {
+        if (str == null || str.length() < 1)
+            return false;
+
+        for (int i=0; i<str.length(); i++) {
+            char c = str.charAt(i);
+
+            if (i == 0 && c == '-')
+                continue;
+            else if (!Character.isDigit(c))
+                return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @return true only if the String contains correct numerical characters and decimal notation.
+     */
+    public static boolean isDecimalNumber(String str) {
+        if (str == null || str.length() < 1)
+            return false;
+
+        boolean parsedPunctuation = false;
+
+        for (int i=0; i<str.length(); i++) {
+            char c = str.charAt(i);
+
+            if (i == 0 && c == '-')
+                continue;
+            else if (!parsedPunctuation && c == '.') {
+                parsedPunctuation = true;
+                continue;
+            }
+            else if (!Character.isDigit(c))
+                return false;
+        }
+
+        return true;
+    }
 }

src/zutil/parser/MathParser.java

@@ -53,7 +53,7 @@ public class MathParser {
         MathOperation current = null;
 
         if (!Character.isWhitespace(c)) {
-            if (isNumber(c)) {
+            if (Character.isDigit(c)) {
                 temp.append(c);
             } else {
                 Math container = new MathNumber();
@@ -95,10 +95,6 @@ public class MathParser {
             parse(functionString, temp, previous, rootNode);
     }
 
-    private static boolean isNumber(char c) {
-        return Character.isDigit(c);
-    }
-
     private static MathOperation getOperation(char c) {
         switch (c) {
             case '+':

test/zutil/StringUtilTest.java

@@ -29,7 +29,7 @@ import org.junit.Test;
 import java.util.Arrays;
 import java.util.Collections;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 
 public class StringUtilTest {
@@ -80,4 +80,37 @@ public class StringUtilTest {
         assertEquals("animal,monkey,dog", StringUtil.join(",", Arrays.asList("animal", "monkey", "dog")));
         assertEquals("12345", StringUtil.join("", 1,2,3,4,5));
     }
+
+    @Test
+    public void isNumber() {
+        assertFalse(StringUtil.isNumber(null));
+        assertFalse(StringUtil.isNumber(""));
+        assertFalse(StringUtil.isNumber("a"));
+        assertFalse(StringUtil.isNumber("-monkey"));
+        assertFalse(StringUtil.isNumber("-123monkey"));
+        assertTrue(StringUtil.isNumber("0"));
+        assertTrue(StringUtil.isNumber("-1"));
+        assertTrue(StringUtil.isNumber("-500"));
+        assertTrue(StringUtil.isNumber("1"));
+        assertTrue(StringUtil.isNumber("500"));
+    }
+
+    @Test
+    public void isDecimalNumber() {
+        assertFalse(StringUtil.isDecimalNumber(null));
+        assertFalse(StringUtil.isDecimalNumber(""));
+        assertFalse(StringUtil.isDecimalNumber("a"));
+        assertFalse(StringUtil.isDecimalNumber("-monkey"));
+        assertFalse(StringUtil.isDecimalNumber("-123monkey"));
+        assertTrue(StringUtil.isDecimalNumber("0"));
+        assertTrue(StringUtil.isDecimalNumber("-1"));
+        assertTrue(StringUtil.isDecimalNumber("-500"));
+        assertTrue(StringUtil.isDecimalNumber("1"));
+        assertTrue(StringUtil.isDecimalNumber("500"));
+        assertTrue(StringUtil.isDecimalNumber("0.0"));
+        assertTrue(StringUtil.isDecimalNumber("-1.1"));
+        assertTrue(StringUtil.isDecimalNumber("-500.2"));
+        assertTrue(StringUtil.isDecimalNumber("1.3"));
+        assertTrue(StringUtil.isDecimalNumber("500.500"));
+    }
 }