dap4.core.util

Class Convert

java.lang.Object

dap4.core.util.Convert

public abstract class Convert
extends Object

This code manages the conversion between the DAP atomic type system and the CDM atomic type system. The Java type system is also involved because neither DAP nor CDM have perfect mappings to Java.

In any case, this means that we have to use switches that operate on DAP X CDM atomic types and this is really ugly.

* Special note about DAP4 char: this is treated * as equivalent to Byte, so it does not appear here. * Note also, this may turn out to be a really bad idea.

Constructor Summary

Constructors

Constructor and Description
Convert()

Method Summary

Methods

Modifier and Type	Method and Description
static Object	convert(DapType dsttype, DapType srctype, Object value) Convert Object to a value consistent with the given type.
static double	doubleValue(DapType srctype, Object value) Special case of convertValue restricted to numeric conversions Convert numeric value to a double value
static double	forceRange(AtomicType basetype, double value) Force a double value into either float or double range
static long	forceRange(AtomicType basetype, long value) Force a numeric value to be in a specified range Only defined for simple integers (ValueClass LONG) WARNING: unsigned values are forced into the signed size, but the proper bit pattern is maintained.
static Object	fromString(String value, DapType dsttype) Convert string to a value consistent with the base type.
static int	getJavaSize(AtomicType atomtype)
static int	getJavaSize(DapType daptype)
static long	longValue(DapType srctype, Object value) Special case of convertValue restricted to integer conversions Convert numeric value to a value consistent with the given type.
static BigInteger	toBigInteger(long l) UInt64 long values are kept as longs, but to properly process them, it is necessary to convert them to a correct form of BigInteger
static String	toString(Object value, DapType srctype) Convert a value to a string constant
static Object	upcast(Object o, DapType srctype) Given an value from a DapAttribute, convert it to avoid losing information.
static DapType	upcastType(DapType basetype) Given a DapAttribute basetype convert it to avoid losing information.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Convert

public Convert()

Method Detail

upcastType

public static DapType upcastType(DapType basetype)

Given a DapAttribute basetype convert it to avoid losing information. This primarily alters unsigned types

Parameters:

basetype - the basetype of the DapAttribute

Returns:

the upcast DapType

upcast

public static Object upcast(Object o,
            DapType srctype)

Given an value from a DapAttribute, convert it to avoid losing information. This primarily alters unsigned types

Parameters:

o - the object to upcast

srctype - the basetype of the DapAttribute

Returns:

the upcast value

getJavaSize

public static int getJavaSize(DapType daptype)

getJavaSize

public static int getJavaSize(AtomicType atomtype)

convert

public static Object convert(DapType dsttype,
             DapType srctype,
             Object value)

Convert Object to a value consistent with the given type. This is the primary conversion method.

Parameters:

dsttype - Type to which the object is to be converted.

srctype - Assumed type of the value; must be consistent in sense that if srctype == float32, then e.g value instanceof double must be true.

value - The object to convert

Returns:

converted value as an object

Throws:

ConversionException - if cannot convert

longValue

public static long longValue(DapType srctype,
             Object value)

Special case of convertValue restricted to integer conversions

Convert numeric value to a value consistent with the given type.

Parameters:

srctype - Assumed type of the value; must be a numeric type

value - The object to convert; it is an instance of Long or Double

Returns:

converted value as a long. but is guaranteed to be in the proper range for dsttype.

Throws:

ConversionException - if cannot convert (including out of range)

doubleValue

public static double doubleValue(DapType srctype,
                 Object value)

Special case of convertValue restricted to numeric conversions

Convert numeric value to a double value

Parameters:

srctype - Assumed type of the value; must be a numeric type

value - The object to convert

Returns:

converted value as a double but is guaranteed to be in the proper range for dsttype.

Throws:

ConversionException - if cannot convert (including out of range)

toBigInteger

public static BigInteger toBigInteger(long l)

UInt64 long values are kept as longs, but to properly process them, it is necessary to convert them to a correct form of BigInteger

Parameters:

l - The long value

Returns:

A proper non-negative BigInteger

forceRange

public static long forceRange(AtomicType basetype,
              long value)

Force a numeric value to be in a specified range Only defined for simple integers (ValueClass LONG) WARNING: unsigned values are forced into the signed size, but the proper bit pattern is maintained. The term "force" means that if the value is outside the typed min/max values, it is pegged to the min or max value depending on the sign. Note that truncation is not used.

Parameters:

basetype - the type to force value to in range

value - the value to force

Returns:

forced value

Throws:

ConversionException - if forcing is not possible

forceRange

public static double forceRange(AtomicType basetype,
                double value)
                         throws DapException

Force a double value into either float or double range

Parameters:

basetype - the type to force value to in range

value - the value to force

Returns:

forced value

Throws:

DapException - if forcing is not possible

fromString

public static Object fromString(String value,
                DapType dsttype)

Convert string to a value consistent with the base type. Primarily used for attribute value conversion.

Parameters:

value - the string to convert

dsttype - target type for the conversion

Returns:

converted value as an object

Throws:

ConversionException - if cannot convert

toString

public static String toString(Object value,
              DapType srctype)

Convert a value to a string constant

Parameters:

value - The object to convert

srctype - The assumed type of the value

Returns:

value in string form