REXP (JRI 0.9-9 API)

java.lang.Object
- org.rosuda.JRI.REXP

```
public class REXP
extends Object
```
This class encapsulates and caches R objects as returned from R. Currently it only converts certain SEXPs references from R into Java obejcts, but eventually bi-directional support should be added. The currently supported objects are string, integer and numeric vectors. All other types can be accessed only using xp reference and RNI methods.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`ANYSXP`
`static int`	`BCODESXP`
`static int`	`BUILTINSXP`
`static int`	`CHARSXP`
`static int`	`CLOSXP`
`static int`	`CPLXSXP`
`static int`	`DOTSXP`
`static int`	`ENVSXP`
`static int`	`EXPRSXP`
`static int`	`EXTPTRSXP`
`static int`	`FUNSXP`
`static int`	`INTSXP`
`static int`	`LANGSXP`
`static int`	`LGLSXP`
`static int`	`LISTSXP`
`static int`	`NILSXP`
`static int`	`PROMSXP`
`static int`	`RAWSXP`
`static int`	`REALSXP`
`int`	`rtype` native type of the represented expression (see ...SXP constants in R).
`static int`	`S4SXP`
`static int`	`SPECIALSXP`
`static int`	`STRSXP`
`static int`	`SYMSXP`
`static int`	`VECSXP`
`static int`	`WEAKREFSXP`
`long`	`xp` native reference to the SEXP represented in R.
`static int`	`XT_ARRAY_BOOL` xpression type: RBool[]
`static int`	`XT_ARRAY_BOOL_INT` xpression type: int[] to be interpreted as boolean
`static int`	`XT_ARRAY_BOOL_UA` internal use only!
`static int`	`XT_ARRAY_DOUBLE` xpression type: double[]
`static int`	`XT_ARRAY_INT` xpression type: int[]
`static int`	`XT_ARRAY_STR` xpression type: String[] (currently not used, Vector is used instead)
`static int`	`XT_BOOL` xpression type: RBool
`static int`	`XT_CLOS` xpression type: closure (there is no java class for that type (yet?).
`static int`	`XT_DOUBLE` xpression type: double
`static int`	`XT_FACTOR` xpression type: RFactor; this XT is internally generated (ergo is does not come from Rsrv.h) to support RFactor class which is built from XT_ARRAY_INT
`static int`	`XT_INT` xpression type: integer
`static int`	`XT_LANG` xpression type: language construct (currently content is same as list)
`static int`	`XT_LIST` xpression type: RList
`static int`	`XT_NONE` xpression type: pure reference, no internal type conversion performed
`static int`	`XT_NULL` xpression type: NULL
`static int`	`XT_STR` xpression type: String
`static int`	`XT_SYM` xpression type: symbol (content is symbol name: String)
`static int`	`XT_UNKNOWN` xpression type: unknown; no assumptions can be made about the content
`static int`	`XT_VECTOR` xpression type: Vector

Constructor Summary

Constructors
Constructor and Description
`REXP()` construct a new, empty (NULL) expression w/o attribute
`REXP(boolean[] val)` construct new expression with the contents of a boolean vector
`REXP(double[] val)` construct a new xpression of type XT_ARRAY_DOUBLE and content val
`REXP(int[] val)` construct a new xpression of type XT_ARRAY_INT and content val
`REXP(int t, Object o)` construct a new xpression of type t and content o, but no attribute
`REXP(int t, Object o, REXP at)` construct a new xpression of type t, content o and attribute at
`REXP(Rengine re, long exp)` create a REXP directly from a R SEXP reference.
`REXP(Rengine re, long exp, boolean convert)`
`REXP(String[] val)` construct a new xpression of type XT_ARRAY_INT and content val

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`RBool`	`asBool()` get content of the REXP as `RBool` (if it is one)
`double`	`asDouble()` get content of the REXP as double (if it is one)
`double[]`	`asDoubleArray()` get content of the REXP as an array of doubles.
`double[][]`	`asDoubleMatrix()` returns the content of the REXP as a matrix of doubles (2D-array: m[rows][cols]).
`RFactor`	`asFactor()` get content of the REXP as `RFactor` (if it is one)
`int`	`asInt()` get content of the REXP as int (if it is one)
`int[]`	`asIntArray()` get content of the REXP as an array of integers.
`RList`	`asList()` get content of the REXP as `RList` if the contents is a list or a generic vector
`double[][]`	`asMatrix()` this is just an alias for `asDoubleMatrix()`.
`String`	`asString()` return the first element of a character vector if this REXP is a character vector of length 1 or more, return `null` otherwise
`String[]`	`asStringArray()` return the contents of this REXP as an array of strings if this REXP is a character vector, return `null` otherwise
`String`	`asSymbolName()` return the name of the symbol represented by this REXP if is it a symbol or `null` otherwise
`RVector`	`asVector()` get content of the REXP as `Vector` (if it is one)
`protected void`	`finalize()`
`REXP`	`getAttribute(String name)` retrieve a specific attribute.
`REXP`	`getAttributes()` get attributes of the REXP.
`Object`	`getContent()` get raw content.
`int`	`getType()` get xpression type (see XT_.. constants) of the content.
`static String`	`quoteString(String s)`
`String`	`toString()` displayable contents of the expression.
`static String`	`xtName(int xt)` returns human-readable name of the xpression type as string.

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - XT_NULL
```
public static final int XT_NULL
```
    xpression type: NULL
    
    See Also:
    
    Constant Field Values
  - XT_INT
```
public static final int XT_INT
```
    xpression type: integer
    
    See Also:
    
    Constant Field Values
  - XT_DOUBLE
```
public static final int XT_DOUBLE
```
    xpression type: double
    
    See Also:
    
    Constant Field Values
  - XT_STR
```
public static final int XT_STR
```
    xpression type: String
    
    See Also:
    
    Constant Field Values
  - XT_LANG
```
public static final int XT_LANG
```
    xpression type: language construct (currently content is same as list)
    
    See Also:
    
    Constant Field Values
  - XT_SYM
```
public static final int XT_SYM
```
    xpression type: symbol (content is symbol name: String)
    
    See Also:
    
    Constant Field Values
  - XT_BOOL
```
public static final int XT_BOOL
```
    xpression type: RBool
    
    See Also:
    
    Constant Field Values
  - XT_VECTOR
```
public static final int XT_VECTOR
```
    xpression type: Vector
    
    See Also:
    
    Constant Field Values
  - XT_LIST
```
public static final int XT_LIST
```
    xpression type: RList
    
    See Also:
    
    Constant Field Values
  - XT_CLOS
```
public static final int XT_CLOS
```
    xpression type: closure (there is no java class for that type (yet?). currently the body of the closure is stored in the content part of the REXP. Please note that this may change in the future!)
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_INT
```
public static final int XT_ARRAY_INT
```
    xpression type: int[]
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_DOUBLE
```
public static final int XT_ARRAY_DOUBLE
```
    xpression type: double[]
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_STR
```
public static final int XT_ARRAY_STR
```
    xpression type: String[] (currently not used, Vector is used instead)
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_BOOL_UA
```
public static final int XT_ARRAY_BOOL_UA
```
    internal use only! this constant should never appear in a REXP
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_BOOL
```
public static final int XT_ARRAY_BOOL
```
    xpression type: RBool[]
    
    See Also:
    
    Constant Field Values
  - XT_ARRAY_BOOL_INT
```
public static final int XT_ARRAY_BOOL_INT
```
    xpression type: int[] to be interpreted as boolean
    
    See Also:
    
    Constant Field Values
  - XT_UNKNOWN
```
public static final int XT_UNKNOWN
```
    xpression type: unknown; no assumptions can be made about the content
    
    See Also:
    
    Constant Field Values
  - XT_NONE
```
public static final int XT_NONE
```
    xpression type: pure reference, no internal type conversion performed
    
    See Also:
    
    Constant Field Values
  - XT_FACTOR
```
public static final int XT_FACTOR
```
    xpression type: RFactor; this XT is internally generated (ergo is does not come from Rsrv.h) to support RFactor class which is built from XT_ARRAY_INT
    
    See Also:
    
    Constant Field Values
  - NILSXP
```
public static final int NILSXP
```
    See Also:
    
    Constant Field Values
  - SYMSXP
```
public static final int SYMSXP
```
    See Also:
    
    Constant Field Values
  - LISTSXP
```
public static final int LISTSXP
```
    See Also:
    
    Constant Field Values
  - CLOSXP
```
public static final int CLOSXP
```
    See Also:
    
    Constant Field Values
  - ENVSXP
```
public static final int ENVSXP
```
    See Also:
    
    Constant Field Values
  - PROMSXP
```
public static final int PROMSXP
```
    See Also:
    
    Constant Field Values
  - LANGSXP
```
public static final int LANGSXP
```
    See Also:
    
    Constant Field Values
  - SPECIALSXP
```
public static final int SPECIALSXP
```
    See Also:
    
    Constant Field Values
  - BUILTINSXP
```
public static final int BUILTINSXP
```
    See Also:
    
    Constant Field Values
  - CHARSXP
```
public static final int CHARSXP
```
    See Also:
    
    Constant Field Values
  - LGLSXP
```
public static final int LGLSXP
```
    See Also:
    
    Constant Field Values
  - INTSXP
```
public static final int INTSXP
```
    See Also:
    
    Constant Field Values
  - REALSXP
```
public static final int REALSXP
```
    See Also:
    
    Constant Field Values
  - CPLXSXP
```
public static final int CPLXSXP
```
    See Also:
    
    Constant Field Values
  - STRSXP
```
public static final int STRSXP
```
    See Also:
    
    Constant Field Values
  - DOTSXP
```
public static final int DOTSXP
```
    See Also:
    
    Constant Field Values
  - ANYSXP
```
public static final int ANYSXP
```
    See Also:
    
    Constant Field Values
  - VECSXP
```
public static final int VECSXP
```
    See Also:
    
    Constant Field Values
  - EXPRSXP
```
public static final int EXPRSXP
```
    See Also:
    
    Constant Field Values
  - BCODESXP
```
public static final int BCODESXP
```
    See Also:
    
    Constant Field Values
  - EXTPTRSXP
```
public static final int EXTPTRSXP
```
    See Also:
    
    Constant Field Values
  - WEAKREFSXP
```
public static final int WEAKREFSXP
```
    See Also:
    
    Constant Field Values
  - RAWSXP
```
public static final int RAWSXP
```
    See Also:
    
    Constant Field Values
  - S4SXP
```
public static final int S4SXP
```
    See Also:
    
    Constant Field Values
  - FUNSXP
```
public static final int FUNSXP
```
    See Also:
    
    Constant Field Values
  - xp
```
public long xp
```
    native reference to the SEXP represented in R. It's usually a pointer, but can be any handle obtained from the engine. This reference can be used when calling RNI commands directly.
  - rtype
```
public int rtype
```
    native type of the represented expression (see ...SXP constants in R). Please note that this type is cached and may have changed in the meantime. If the possibility of changing type exists (mainly list/lang) then use rniExpType to make sure
- Constructor Detail
  - REXP
```
public REXP(Rengine re,
            long exp)
```
    create a REXP directly from a R SEXP reference. SEXP types STRSXP, INTSXP and REALSXP are automatically converted. All others are represented as SEXP references only.
  - REXP
```
public REXP(Rengine re,
            long exp,
            boolean convert)
```
  - REXP
```
public REXP()
```
    construct a new, empty (NULL) expression w/o attribute
  - REXP
```
public REXP(int t,
            Object o)
```
    construct a new xpression of type t and content o, but no attribute
    
    Parameters:
    
    t - xpression type (XT_...)
    
    o - content
  - REXP
```
public REXP(int t,
            Object o,
            REXP at)
```
    construct a new xpression of type t, content o and attribute at
    
    Parameters:
    
    t - xpression type
    
    o - content
    
    at - attribute
  - REXP
```
public REXP(double[] val)
```
    construct a new xpression of type XT_ARRAY_DOUBLE and content val
    
    Parameters:
    
    val - array of doubles to store in the REXP
  - REXP
```
public REXP(int[] val)
```
    construct a new xpression of type XT_ARRAY_INT and content val
    
    Parameters:
    
    val - array of integers to store in the REXP
  - REXP
```
public REXP(String[] val)
```
    construct a new xpression of type XT_ARRAY_INT and content val
    
    Parameters:
    
    val - array of integers to store in the REXP
  - REXP
```
public REXP(boolean[] val)
```
    construct new expression with the contents of a boolean vector
    
    Parameters:
    
    val - contents
    
    Since:
    
    JRI 0.3-2
- Method Detail
  - finalize
```
protected void finalize()
                 throws Throwable
```
    Overrides:
    
    finalize in class Object
    
    Throws:
    
    Throwable
  - getAttributes
```
public REXP getAttributes()
```
    get attributes of the REXP. In R every object can have attached attribute xpression. Some more complex structures such as classes are built that way.
    
    Returns:
    
    attribute xpression or null if there is none associated
    
    Since:
    
    JRI 0.3, replaces getAttribute() but should be avoided if possible - use getAttribute(String) instead.
  - getAttribute
```
public REXP getAttribute(String name)
```
    retrieve a specific attribute.
    Note: the current representation fetches the attribute ad-hoc, so it breaks the assumption that the expression is no longer accessed after the constructor was called. This should change in the future.
    
    Parameters:
    
    name - name of the attribute
    
    Returns:
    
    REXP containing the attribute or null if the attribute doesn't exist. The conversion flag is inherited from this REXP.
    
    Since:
    
    JRI 0.3
  - getContent
```
public Object getContent()
```
    get raw content. Use as... methods to retrieve contents of known type.
    
    Returns:
    
    content of the REXP
  - getType
```
public int getType()
```
    get xpression type (see XT_.. constants) of the content. It defines the type of the content object.
    
    Returns:
    
    xpression type
  - asString
```
public String asString()
```
    return the first element of a character vector if this REXP is a character vector of length 1 or more, return null otherwise
  - asSymbolName
```
public String asSymbolName()
```
    return the name of the symbol represented by this REXP if is it a symbol or null otherwise
  - asStringArray
```
public String[] asStringArray()
```
    return the contents of this REXP as an array of strings if this REXP is a character vector, return null otherwise
  - asInt
```
public int asInt()
```
    get content of the REXP as int (if it is one)
    
    Returns:
    
    int content or 0 if the REXP is no integer
  - asDouble
```
public double asDouble()
```
    get content of the REXP as double (if it is one)
    
    Returns:
    
    double content or 0.0 if the REXP is no double
  - asVector
```
public RVector asVector()
```
    get content of the REXP as Vector (if it is one)
    
    Returns:
    
    Vector content or null if the REXP is no Vector
  - asFactor
```
public RFactor asFactor()
```
    get content of the REXP as RFactor (if it is one)
    
    Returns:
    
    RFactor content or null if the REXP is no factor
  - asList
```
public RList asList()
```
    get content of the REXP as RList if the contents is a list or a generic vector
    
    Returns:
    
    RList content or null if the REXP is neither a list nor a generic vector
  - asBool
```
public RBool asBool()
```
    get content of the REXP as RBool (if it is one)
    
    Returns:
    
    RBool content or null if the REXP is no logical value
  - asDoubleArray
```
public double[] asDoubleArray()
```
    get content of the REXP as an array of doubles. Array of integers, single double and single integer are automatically converted into such an array if necessary.
    
    Returns:
    
    double[] content or null if the REXP is not a array of doubles or integers
  - asIntArray
```
public int[] asIntArray()
```
    get content of the REXP as an array of integers. Unlike asDoubleArray() NO automatic conversion is done if the content is not an array of the correct type, because there is no canonical representation of doubles as integers. A single integer is returned as an array of the length 1. This method can be also used to access a logical array in its integer form (0=FALSE, 1=TRUE, 2=NA).
    
    Returns:
    
    int[] content or null if the REXP is not a array of integers
  - asDoubleMatrix
```
public double[][] asDoubleMatrix()
```
    returns the content of the REXP as a matrix of doubles (2D-array: m[rows][cols]). This is the same form as used by popular math packages for Java, such as JAMA. This means that following leads to desired results:
    Matrix m=new Matrix(c.eval("matrix(c(1,2,3,4,5,6),2,3)").asDoubleMatrix());
    
    Returns:
    
    2D array of doubles in the form double[rows][cols] or null if the contents is no 2-dimensional matrix of doubles
  - asMatrix
```
public double[][] asMatrix()
```
    this is just an alias for asDoubleMatrix().
  - toString
```
public String toString()
```
    displayable contents of the expression. The expression is traversed recursively if aggregation types are used (Vector, List, etc.)
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    String descriptive representation of the xpression
  - quoteString
```
public static String quoteString(String s)
```
  - xtName
```
public static String xtName(int xt)
```
    returns human-readable name of the xpression type as string. Arrays are denoted by a trailing asterisk (*).
    
    Parameters:
    
    xt - xpression type
    
    Returns:
    
    name of the xpression type

Class REXP

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

XT_NULL

XT_INT

XT_DOUBLE

XT_STR

XT_LANG

XT_SYM

XT_BOOL

XT_VECTOR

XT_LIST

XT_CLOS

XT_ARRAY_INT

XT_ARRAY_DOUBLE

XT_ARRAY_STR

XT_ARRAY_BOOL_UA

XT_ARRAY_BOOL

XT_ARRAY_BOOL_INT

XT_UNKNOWN

XT_NONE

XT_FACTOR

NILSXP

SYMSXP

LISTSXP

CLOSXP

ENVSXP

PROMSXP

LANGSXP

SPECIALSXP

BUILTINSXP

CHARSXP

LGLSXP

INTSXP

REALSXP

CPLXSXP

STRSXP

DOTSXP

ANYSXP

VECSXP

EXPRSXP

BCODESXP

EXTPTRSXP

WEAKREFSXP

RAWSXP

S4SXP

FUNSXP

xp

rtype

Constructor Detail

REXP

REXP

REXP

REXP

REXP

REXP

REXP

REXP

REXP

Method Detail

finalize

getAttributes

getAttribute

getContent

getType

asString

asSymbolName

asStringArray

asInt

asDouble

asVector

asFactor

asList

asBool

asDoubleArray

asIntArray

asDoubleMatrix