de.zib.scalaris
Class ErlangValue

java.lang.Object
  de.zib.scalaris.ErlangValue

All Implemented Interfaces:

Comparable<ErlangValue>

Direct Known Subclasses:

ErlangValueBitString, ErlangValueFastString

public class ErlangValue
extends Object
implements Comparable<ErlangValue>

Encapsulates a result from a read operation on scalaris. See ErlangValue(Object) for a list of compatible types.

Since:

3.0

Version:

3.19

Author:

Nico Kruber, kruber@zib.de

Nested Class Summary

static interface	ErlangValue.ListElementConverter<T> Converts list elements to a desired type.
static class	ErlangValue.StringListElementConverter Converts list elements to Strings.

Constructor Summary

ErlangValue(OtpErlangObject value)
Creates a new object wrapping the given erlang value.

ErlangValue(T value)
Creates a new object from a given set of Java types.

Method Summary

BigInteger	bigIntValue() Returns the Java BigInteger value of the wrapped erlang value.
List<byte[]>	binaryListValue() Returns a list of byte[] values of the wrapped erlang value.
byte[]	binaryValue() Returns the Java byte[] value of the wrapped erlang value.
boolean	boolValue() Returns the Java int value of the wrapped erlang value.
int	compareTo(ErlangValue o) Compares two erlang values by their string representation (expensive!).
static <T> OtpErlangObject	convertToErlang(T value) Converts a (supported) Java type to an OtpErlangObject.
List<Double>	doubleListValue() Returns a list of Double values of the wrapped erlang value.
double	doubleValue() Returns the Java double value of the wrapped erlang value.
boolean	equals(Object obj)
int	hashCode()
int	intValue() Returns the Java int value of the wrapped erlang value.
<T> List<T>	jsonListValue(Class<T> c) Returns a list of JSON objects (as an instance of the given class) of the wrapped erlang value.
Map<String,Object>	jsonValue() Returns a JSON object (as Map<String, Object>) of the wrapped erlang value.
<T> T	jsonValue(Class<T> c) Returns a JSON object (as an instance of the given class) of the wrapped erlang value.
Collection<ErlangValue>	listCollectionValue(Class<? extends Collection<ErlangValue>> clazz) Returns a Collection of mixed Java values (wrapped in ErlangValue objects) of the wrapped erlang value (internally represented as a list in Erlang).
<T> Collection<T>	listCollectionValue(Class<? extends Collection<T>> clazz, ErlangValue.ListElementConverter<T> converter) Returns a Collection of mixed Java values of the wrapped erlang value (internally represented as a list in Erlang).
List<ErlangValue>	listValue() Returns a list of mixed Java values (wrapped in ErlangValue objects) of the wrapped erlang value.
<T> List<T>	listValue(ErlangValue.ListElementConverter<T> converter) Returns a list of mixed Java values of the wrapped erlang value.
List<Long>	longListValue() Returns a list of Long values of the wrapped erlang value.
long	longValue() Returns the Java long value of the wrapped erlang value.
static OtpErlangList	otpObjectToOtpList(OtpErlangObject value) Converts an OtpErlangObject to a OtpErlangList taking special care if the OTP library converted a list to an OtpErlangString.
List<String>	stringListValue() Returns a list of String values of the wrapped erlang value.
String	stringValue() Returns the Java String value of the wrapped erlang value.
String	toString()
OtpErlangObject	value() Gets the original erlang value.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ErlangValue

public ErlangValue(OtpErlangObject value)

Creates a new object wrapping the given erlang value.

Parameters:

value - a value from erlang

ErlangValue

public ErlangValue(T value)
            throws ClassCastException

Creates a new object from a given set of Java types. The following types are supported:

native types

• Boolean - OtpErlangBoolean
• Long - OtpErlangLong
• Integer - OtpErlangLong
• BigInteger - OtpErlangLong
• Double - OtpErlangDouble
• String - OtpErlangString
• byte[] - OtpErlangBinary

composite types

• List<Object> with one of the native types except byte[] or another (supported) list/map - OtpErlangList
• Collection<Object> same as List<Object> (internally represented as a list)
• Map<String, Object> representing a JSON object - OtpErlangTuple

custom types

• OtpErlangObject - an arbitrary erlang value
• ErlangValue

Type Parameters:

T - the type of the value

Parameters:

value - the value to convert to an erlang type

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

Method Detail

convertToErlang

public static <T> OtpErlangObject convertToErlang(T value)
                                       throws ClassCastException

Converts a (supported) Java type to an OtpErlangObject.

Type Parameters:

T - the type of the value

Parameters:

value - the value to convert to an erlang type

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

boolValue

public boolean boolValue()
                  throws ClassCastException

Returns the Java int value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported or the value is too big

Since:

3.3

intValue

public int intValue()
             throws ClassCastException

Returns the Java int value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported or the value is too big

longValue

public long longValue()
               throws ClassCastException

Returns the Java long value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported or the value is too big

bigIntValue

public BigInteger bigIntValue()
                       throws ClassCastException

Returns the Java BigInteger value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

doubleValue

public double doubleValue()
                   throws ClassCastException

Returns the Java double value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

stringValue

public String stringValue()
                   throws ClassCastException

Returns the Java String value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

binaryValue

public byte[] binaryValue()
                   throws ClassCastException

Returns the Java byte[] value of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

jsonValue

public Map<String,Object> jsonValue()
                             throws ClassCastException

Returns a JSON object (as Map<String, Object>) of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

jsonValue

public <T> T jsonValue(Class<T> c)
            throws ClassCastException

Returns a JSON object (as an instance of the given class) of the wrapped erlang value.

Type Parameters:

T - the type of the object to create

Parameters:

c - the class of the created object

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

otpObjectToOtpList

public static OtpErlangList otpObjectToOtpList(OtpErlangObject value)
                                        throws ClassCastException

Converts an OtpErlangObject to a OtpErlangList taking special care if the OTP library converted a list to an OtpErlangString.

Parameters:

value - the value to convert

Returns:

the value as a OtpErlangList

Throws:

ClassCastException - if the conversion fails

listValue

public <T> List<T> listValue(ErlangValue.ListElementConverter<T> converter)
                  throws ClassCastException

Returns a list of mixed Java values of the wrapped erlang value.

Type Parameters:

T - type of the elements in the list

Parameters:

converter - object that converts the list value to the desired type

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

listCollectionValue

public <T> Collection<T> listCollectionValue(Class<? extends Collection<T>> clazz,
                                             ErlangValue.ListElementConverter<T> converter)
                                  throws ClassCastException

Returns a Collection of mixed Java values of the wrapped erlang value (internally represented as a list in Erlang).

Type Parameters:

T - type of the elements in the list

Parameters:

clazz - class of the result type

converter - object that converts the list value to the desired type

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

Since:

3.19

listValue

public List<ErlangValue> listValue()
                            throws ClassCastException

Returns a list of mixed Java values (wrapped in ErlangValue objects) of the wrapped erlang value.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

listCollectionValue

public Collection<ErlangValue> listCollectionValue(Class<? extends Collection<ErlangValue>> clazz)
                                            throws ClassCastException

Returns a Collection of mixed Java values (wrapped in ErlangValue objects) of the wrapped erlang value (internally represented as a list in Erlang).

Parameters:

clazz - class of the result type

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

Since:

3.19

longListValue

public List<Long> longListValue()
                         throws ClassCastException

Returns a list of Long values of the wrapped erlang value. Provided for convenience.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

See Also:

listValue(ListElementConverter)

doubleListValue

public List<Double> doubleListValue()
                             throws ClassCastException

Returns a list of Double values of the wrapped erlang value. Provided for convenience.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

See Also:

listValue(ListElementConverter)

stringListValue

public List<String> stringListValue()
                             throws ClassCastException

Returns a list of String values of the wrapped erlang value. Provided for convenience.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

See Also:

listValue(ListElementConverter)

binaryListValue

public List<byte[]> binaryListValue()
                             throws ClassCastException

Returns a list of byte[] values of the wrapped erlang value. Provided for convenience.

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

See Also:

listValue(ListElementConverter)

jsonListValue

public <T> List<T> jsonListValue(Class<T> c)
                      throws ClassCastException

Returns a list of JSON objects (as an instance of the given class) of the wrapped erlang value. Provided for convenience.

Type Parameters:

T - the type of the object to create as a list element

Parameters:

c - the class of the created object

Returns:

the converted value

Throws:

ClassCastException - if thrown if a conversion is not possible, i.e. the type is not supported

Since:

3.5

See Also:

listValue(ListElementConverter)

value

public OtpErlangObject value()

Gets the original erlang value.

Returns:

the value as reported by erlang

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

compareTo

public int compareTo(ErlangValue o)

Compares two erlang values by their string representation (expensive!).

Specified by:

compareTo in interface Comparable<ErlangValue>

Parameters:

o - another erlang value