Package org.apache.xmlgraphics.util
Class DoubleFormatUtil
java.lang.Object
org.apache.xmlgraphics.util.DoubleFormatUtil
This class implements fast, thread-safe format of a double value
with a given number of decimal digits.
The contract for the format methods is this one: if the source is greater than or equal to 1 (in absolute value), use the decimals parameter to define the number of decimal digits; else, use the precision parameter to define the number of decimal digits.
A few examples (consider decimals being 4 and precision being 8):
- 0.0 should be rendered as "0"
- 0.1 should be rendered as "0.1"
- 1234.1 should be rendered as "1234.1"
- 1234.1234567 should be rendered as "1234.1235" (note the trailing 5! Rounding!)
- 1234.00001 should be rendered as "1234"
- 0.00001 should be rendered as "0.00001" (here you see the effect of the "precision" parameter)
- 0.00000001 should be rendered as "0.00000001"
- 0.000000001 should be rendered as "0"
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Method Summary
Modifier and TypeMethodDescriptionstatic void
formatDouble
(double source, int decimals, int precision, StringBuffer target) Rounds the given source value at the given precision and writes the rounded value into the given targetstatic void
formatDoubleFast
(double source, int decimals, int precision, StringBuffer target) Rounds the given source value at the given precision and writes the rounded value into the given targetstatic void
formatDoublePrecise
(double source, int decimals, int precision, StringBuffer target) Rounds the given source value at the given precision and writes the rounded value into the given targetstatic int
getExponant
(double value) Returns the exponent of the given valuestatic long
tenPow
(int n) Returns ten to the power of n
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Method Details
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formatDouble
Rounds the given source value at the given precision and writes the rounded value into the given target- Parameters:
source
- the source value to rounddecimals
- the decimals to round at (use if abs(source) ≥ 1.0)precision
- the precision to round at (use if abs(source) < 1.0)target
- the buffer to write to
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formatDoublePrecise
public static void formatDoublePrecise(double source, int decimals, int precision, StringBuffer target) Rounds the given source value at the given precision and writes the rounded value into the given targetThis method internally uses the String representation of the source value, in order to avoid any double precision computation error.
- Parameters:
source
- the source value to rounddecimals
- the decimals to round at (use if abs(source) ≥ 1.0)precision
- the precision to round at (use if abs(source) < 1.0)target
- the buffer to write to
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tenPow
public static long tenPow(int n) Returns ten to the power of n- Parameters:
n
- the nth power of ten to get- Returns:
- ten to the power of n
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formatDoubleFast
public static void formatDoubleFast(double source, int decimals, int precision, StringBuffer target) Rounds the given source value at the given precision and writes the rounded value into the given targetThis method internally uses double precision computation and rounding, so the result may not be accurate (see formatDouble method for conditions).
- Parameters:
source
- the source value to rounddecimals
- the decimals to round at (use if abs(source) ≥ 1.0)precision
- the precision to round at (use if abs(source) < 1.0)target
- the buffer to write to
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getExponant
public static int getExponant(double value) Returns the exponent of the given value- Parameters:
value
- the value to get the exponent from- Returns:
- the value's exponent
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