converters: Convert between R objects and their Java representation.

Description

These functions are not intended for the end user. They are used to match objects being translated between R and Java to functions that perform the conversion. They are useful for understanding the overall conversion process, and as examples for writing custom conversions.

Usage

# 'robject' converters
cvtCharacterFromJava(x, thisClassName)
cvtCharacterToJava(x, ...)
matchCharacterToJava(x, ...)
cvtIntegerFromJava(x, thisClassName)
cvtIntegerToJava(x, ...)
matchIntegerToJava(x, ...)
cvtLogicalFromJava(x, thisClassName)
cvtLogicalToJava(x, ...)
matchLogicalToJava(x, ...)
cvtNumericFromJava(x, thisClassName)
cvtNumericToJava(x, ...)
matchNumericToJava(x, ...)
cvtRawFromJava(x, thisClassName)
cvtRawToJava(x, ...)
matchRawToJava(x, ...)
cvtComplexFromJava(x, thisClassName)
cvtComplexToJava(x, ...)
matchComplexToJava(x, ...)
cvtVectorFromJava(x, thisClassName)
cvtVectorToJava(x, ...)
matchVectorToJava(x, ...)
cvtListFromJava(x, thisClassName)
cvtListToJava(x, ...)
matchListToJava(x, ...)
cvtArrayFromJava(x, thisClassName)
cvtArrayToJava(x, ...)
matchArrayToJava(x, ...)
cvtMatrixFromJava(x, thisClassName)
cvtMatrixToJava(x, ...)
matchMatrixToJava(x, ...)
cvtFactorFromJava(x, thisClassName)
cvtFactorToJava(x, ...)
matchFactorToJava(x, ...)
cvtDataFrameFromJava(x, thisClassName)
cvtDataFrameToJava(x, ...)
matchDataFrameToJava(x, ...)
cvtEnvFromJava(x, thisClassName)
cvtEnvToJava(x, ...)
matchEnvToJava(x, ...)
cvtUnknownFromJava(x, thisClassName)
cvtUnknownToJava(x, ...)
matchUnknownToJava(x, ...)
cvtFileReferencesFromJava(x, thisClassName)
cvtFileReferencesToJava(x, ...)
matchFileReferencesToJava(x, ...)
## 'javalib' converters
cvtCharacterToJava2(x, ...)
matchCharacterToJava2(x, ...)
cvtIntegerToJava2(x, ...)
matchIntegerToJava2(x, ...)
cvtLogicalToJava2(x, ...)
matchLogicalToJava2(x, ...)
cvtNumericToJava2(x, ...)
matchNumericToJava2(x, ...)
cvtRawToJava2(x, ...)
matchRawToJava2(x, ...)
cvtComplexFromJava2(x, thisClassName)
cvtComplexToJava2(x, ...)
matchComplexToJava2(x, ...)
cvtListToJava2(x, ...)
matchListToJava2(x, ...)
cvtFactorFromJava2(x, thisClassName)
cvtFactorToJava2(x, ...)
matchFactorToJava2(x, ...)
cvtDataFrameFromJava2(x, thisClassName)
cvtDataFrameToJava2(x, ...)
matchDataFrameToJava2(x, ...)
cvtCharArrayFromJava2(x, thisClassName)
cvtCharArrayToJava2(x, ...)
matchCharArrayToJava2(x, ...)
cvtIntegerArrayFromJava2(x, thisClassName)
cvtIntegerArrayToJava2(x, ...)
matchIntegerArrayToJava2(x, ...)
cvtNumericArrayFromJava2(x, thisClassName)
cvtNumericArrayToJava2(x, ...)
matchNumericArrayToJava2(x, ...)
cvtLogicalArrayFromJava2(x, thisClassName)
cvtLogicalArrayToJava2(x, ...)
matchLogicalArrayToJava2(x, ...)
cvtRawArrayFromJava2(x, thisClassName)
cvtRawArrayToJava2(x, ...)
matchRawArrayToJava2(x, ...)
cvtComplexArrayFromJava2(x, thisClassName)
cvtComplexArrayToJava2(x, ...)
matchComplexArrayToJava2(x, ...)
cvtCharMatrixFromJava2(x, thisClassName)
cvtCharMatrixToJava2(x, ...)
matchCharMatrixToJava2(x, ...)
cvtIntegerMatrixFromJava2(x, thisClassName)
cvtIntegerMatrixToJava2(x, ...)
matchIntegerMatrixToJava2(x, ...)
cvtNumericMatrixFromJava2(x, thisClassName)
cvtNumericMatrixToJava2(x, ...)
matchNumericMatrixToJava2(x, ...)
cvtLogicalMatrixFromJava2(x, thisClassName)
cvtLogicalMatrixToJava2(x, ...)
matchLogicalMatrixToJava2(x, ...)
cvtRawMatrixFromJava2(x, thisClassName)
cvtRawMatrixToJava2(x, ...)
matchRawMatrixToJava2(x, ...)
cvtComplexMatrixFromJava2(x, thisClassName)
cvtComplexMatrixToJava2(x, ...)
matchComplexMatrixToJava2(x, ...)
cvtEnvFromJava2(x, thisClassName)
cvtEnvToJava2(x, ...)
matchEnvToJava2(x, ...)
cvtFileReferencesFromJava2(x, thisClassName)
cvtFileReferencesToJava2(x, ...)
matchFileReferencesToJava2(x, ...)

Arguments

Either a reference to the Java object to be converted (e.g. cvtArrayFromJava), or a R object.

...

Additional arguments passed to SJava

thisClassName

Character representation of the class of the Java object that x refers to.

Value

The cvt*ToJava functions return references to Java objects. The cvt*FromJava functions return instances of R objects. match* return TRUE when the match criterion is satisfied, FALSE otherwise.

Details

The cvt* functions take an instance of an object of one language (R or Java) and convert it to an instance of the other language.

The match* functions take an instance of an object, and return a logical indicating whether the match criterion is satisified.

The convention used in RWebServices is to name the functions as ToJava or FromJava.

RWebServices installs one of two types of converters. The the function regAddonCvt installs converters for the ‘robject’ model, where R objects are represented in a hierarchy of Java objects that attempt to capture important attributes of the R instances. The mapping is as follows:

Java

raw

RRaw

logical

RLogical

character

RChar

integer

RInteger

numeric

RNumeric

complex

RComplex

list RList factor RFactor data.frame RDataFrame environment REnvironment

array RArray matrix RMatrix

The ‘other’ converter is invoked when no other converter matches. cvtUnknownToJava creates an instance of the Java class rservices.RUnknown to hold the class, length, and string representation (i.e., the result of print) of the contents of the R object. cvtUnknownFromJava converts rservices.RUnknown instance to a R S4 instance if the original R object is a S4 instance, otherwise the function returns a list with the same class and length as the original R object. This is likely to be very unsatisfactory.

The function regAddonCvt2 installs converters for the ‘javalib’ model, where R objects are represented by Java primitive types where possible; NA values are not permitted. The mapping is as follows:

Java

raw

byte[]

logical

boolean[]

character

String[]

integer

int[]

numeric

double[]

complex

RJComplex

list Object[] factor RJFactor data.frame RJDataFrame environment java.util.HashMap

‘*’Array, RJ‘*’Array ‘*’Matrix, RJ‘*’Matrix

FileReferences RJFileReferences

The ‘*’Array and ‘*’Matrix and array entries represent instances of the ArrayAndMatrix-class, which provide strong type information about the typeof elements (raw, logical, character, integer, numeric, complex) in arrays and matricies.

References

http://www.omegahat.org/RSJava/index.html

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