Performance improvement

jettison-json · Jun 9, 2022 · cfc7382 · cfc7382
1 parent d371468
commit cfc7382
Showing 1 changed file with 186 additions and 27 deletions.
diff --git a/src/main/java/org/codehaus/jettison/mapped/DefaultConverter.java b/src/main/java/org/codehaus/jettison/mapped/DefaultConverter.java
@@ -33,35 +33,194 @@ public void setEnforce32BitInt(boolean enforce32BitInt) {
 
 	public Object convertToJSONPrimitive(String text) {
         if(text == null) return text;
-		Object primitive = null;
-		// Attempt to convert to Integer
-		try {
-			primitive = enforce32BitInt ? Integer.valueOf(text) : Long.valueOf(text);
-		} catch (Exception e) {/**/}
-		// Attempt to convert to double
-		if (primitive == null) {
-			try {
-				Double v = Double.valueOf(text);
-                if( !v.isInfinite() && !v.isNaN() ) {
-                    primitive = v;
+
+        // If there's at least one character
+        if (text.length() >= 1) {
+            // find the first character
+            char first = text.charAt(0);
+
+            // Is it incompatible with a number?
+            if ((first < '0' || first > '9') && first != '-') {
+                // Yes it is, so special case check for Boolean values
+                if (first == 't') {
+                    if (text.equals("true")) {
+                       return Boolean.TRUE;
+                    }
+                } else if (first == 'f') {
+                    if (text.equals("false")) {
+                        return Boolean.FALSE;
+                    }
                 }
-                else {
+
+                // Definitely not a Boolean or a number, so return the original value
+                return text;
+            }
+        }
+
+        Object primitive = null;
+
+        if (enforce32BitInt) {
+            primitive = getInteger(text);
+        } else {
+            primitive = getLong(text);
+        }
+
+        if (primitive == null) {
+            Double dbl = getDouble(text);
+
+            if (dbl != null) {
+                if (dbl.isInfinite() || dbl.isNaN()) {
                     primitive = text;
                 }
-			} catch (Exception e) {/**/}
-		}
-		// Attempt to convert to boolean
-		if (primitive == null) {
-			if(text.trim().equalsIgnoreCase("true") || text.trim().equalsIgnoreCase("false")) {
-				primitive = Boolean.valueOf(text);
-			}
-		}
-
-		if (primitive == null || !primitive.toString().equals(text)) {
-			// Default String
-			primitive = text;
-		}
-
-		return primitive;
+                else {
+                    primitive = dbl;
+                }
+            }
+        }
+
+        if (primitive == null || !primitive.toString().equals(text)) {
+            // Default String
+            primitive = text;
+        }
+
+        return primitive;
+    }
+
+	private static final int MAX_LENGTH_LONG = String.valueOf(Long.MAX_VALUE).length();
+	private static final int MAX_LENGTH_LONG_NEGATIVE = String.valueOf(Long.MAX_VALUE).length() + 1;
+
+	/**
+     *  Try to get a Long value efficiently, avoiding Exceptions
+     */
+    private static Long getLong(String text)
+    {
+        // handle an empty string
+        if (text.isEmpty()) return null;
+
+        // if the text is too long it can't be a Long
+        if (text.charAt(0) == '-') {
+            if (text.length() > MAX_LENGTH_LONG_NEGATIVE) {
+                return null;
+	        }
+        } else if (text.length() > MAX_LENGTH_LONG) {
+            return null;
+        }
+
+        // Handle a leading minus sign
+        int i = 0;
+        if (text.charAt(0) == '-') {
+            if (text.length() > 1) {
+                i++;
+            } else {
+                return null;
+            }
+        }
+
+        // Check each character is a digit
+        for (; i < text.length(); i++) {
+            if (!Character.isDigit(text.charAt(i))) {
+                return null;
+            }
+        }
+
+        // It looks like it might be a Long, so give it a go
+        try {
+            return Long.parseLong(text);
+        } catch (Exception e) {
+            // It isn't a Long
+            return null;
+        }
+    }
+
+    private static final int MAX_LENGTH_INTEGER = String.valueOf(Integer.MAX_VALUE).length();
+    private static final int MAX_LENGTH_INTEGER_NEGATIVE = String.valueOf(Integer.MAX_VALUE).length() + 1;
+
+    /**
+     *  Try to get an Integer value efficiently, avoiding Exceptions
+     */
+    private static Integer getInteger(String text) {
+        // handle an empty string
+        if (text.isEmpty()) return null;
+
+        // if the text is too long it can't be an Integer
+        if (text.charAt(0) == '-') {
+            if (text.length() > MAX_LENGTH_INTEGER_NEGATIVE) {
+                return null;
+	        }
+        }
+        else if (text.length() > MAX_LENGTH_INTEGER) {
+            return null;
+        }
+
+        // Handle a leading minus sign
+        int i = 0;
+        if (text.charAt(0) == '-') {
+            if (text.length() > 1) {
+                i++;
+            } else {
+                return null;
+            }
+        }
+
+        // Check each character is a digit
+        for (; i < text.length(); i++) {
+            if (!Character.isDigit(text.charAt(i))) {
+                return null;
+            }
+        }
+
+        // It looks like it might be an Integer, so give it a go
+        try {
+            return Integer.parseInt(text);
+        } catch (Exception e) {
+            // It isn't an Integer
+            return null;
+        }
+    }
+
+    /**
+     * Try to get a Double value efficiently, avoiding Exceptions
+     */
+    private static Double getDouble(String text) {
+        boolean foundDP = false;
+        boolean foundExp = false;
+
+        // handle an empty string
+        if (text.isEmpty())
+            return null;
+
+        // Handle a leading minus sign
+        int i = 0;
+        if (text.charAt(0) == '-') {
+            if (text.length() > 1)
+                i++;
+            else
+                return null;
+        }
+
+        // Check each character is a digit
+        for (; i < text.length(); i++) {
+            char next = text.charAt(i);
+            if (!Character.isDigit(next)) {
+                if (next == '.') {
+                    if (foundDP)
+                        return null;
+                    foundDP = true;
+                } else if (next == 'E' || next == 'e') {
+                    if (foundExp)
+                        return null;
+                    foundExp = true;
+                } else
+                    return null;
+            }
+        }
+
+        // It looks like it might be a Double, so give it a go
+        try {
+            return Double.parseDouble(text);
+        } catch (Exception e) {
+            // It isn't a Double
+            return null;
+        }
     }
 }