Package de.zib.scalaris

Class ErlangValue

java.lang.Object

de.zib.scalaris.ErlangValue

All Implemented Interfaces:

java.lang.Comparable<ErlangValue>

Direct Known Subclasses:

ErlangValueBitString, ErlangValueFastString

public class ErlangValue
extends java.lang.Object
implements java.lang.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

Nested Classes

Modifier and Type	Class	Description
static interface	ErlangValue.ListElementConverter<T>	Converts list elements to a desired type.
static class	ErlangValue.StringListElementConverter	Converts list elements to Strings.

Constructor Summary

Constructors

Constructor	Description
ErlangValue(com.ericsson.otp.erlang.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

Modifier and Type	Method	Description
java.math.BigInteger	bigIntValue()	Returns the Java BigInteger value of the wrapped erlang value.
java.util.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> com.ericsson.otp.erlang.OtpErlangObject	convertToErlang(T value)	Converts a (supported) Java type to an OtpErlangObject.
java.util.List<java.lang.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(java.lang.Object obj)
int	hashCode()
int	intValue()	Returns the Java int value of the wrapped erlang value.
<T> java.util.List<T>	jsonListValue(java.lang.Class<T> c)	Returns a list of JSON objects (as an instance of the given class) of the wrapped erlang value.
java.util.Map<java.lang.String,java.lang.Object>	jsonValue()	Returns a JSON object (as Map<String, Object>) of the wrapped erlang value.
<T> T	jsonValue(java.lang.Class<T> c)	Returns a JSON object (as an instance of the given class) of the wrapped erlang value.
java.util.Collection<ErlangValue>	listCollectionValue(java.lang.Class<? extends java.util.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> java.util.Collection<T>	listCollectionValue(java.lang.Class<? extends java.util.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).
java.util.List<ErlangValue>	listValue()	Returns a list of mixed Java values (wrapped in ErlangValue objects) of the wrapped erlang value.
<T> java.util.List<T>	listValue(ErlangValue.ListElementConverter<T> converter)	Returns a list of mixed Java values of the wrapped erlang value.
java.util.List<java.lang.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 com.ericsson.otp.erlang.OtpErlangList	otpObjectToOtpList(com.ericsson.otp.erlang.OtpErlangObject value)	Converts an OtpErlangObject to a OtpErlangList taking special care if the OTP library converted a list to an OtpErlangString.
java.util.List<java.lang.String>	stringListValue()	Returns a list of String values of the wrapped erlang value.
java.lang.String	stringValue()	Returns the Java String value of the wrapped erlang value.
java.lang.String	toString()
com.ericsson.otp.erlang.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(com.ericsson.otp.erlang.OtpErlangObject value)

Creates a new object wrapping the given erlang value.

Parameters:

value - a value from erlang

ErlangValue

public ErlangValue(T value)
            throws java.lang.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:

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

Method Detail

convertToErlang

public static <T> com.ericsson.otp.erlang.OtpErlangObject convertToErlang(T value)
                                                                   throws java.lang.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:

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

boolValue

public boolean boolValue()
                  throws java.lang.ClassCastException

Returns the Java int value of the wrapped erlang value.

Returns:

the converted value

Throws:

java.lang.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 java.lang.ClassCastException

Returns the Java int value of the wrapped erlang value.

Returns:

the converted value

Throws:

java.lang.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 java.lang.ClassCastException

Returns the Java long value of the wrapped erlang value.

Returns:

the converted value

Throws:

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

bigIntValue

public java.math.BigInteger bigIntValue()
                                 throws java.lang.ClassCastException

Returns the Java BigInteger value of the wrapped erlang value.

Returns:

the converted value

Throws:

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

doubleValue

public double doubleValue()
                   throws java.lang.ClassCastException

Returns the Java double value of the wrapped erlang value.

Returns:

the converted value

Throws:

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

stringValue

public java.lang.String stringValue()
                             throws java.lang.ClassCastException

Returns the Java String value of the wrapped erlang value.

Returns:

the converted value

Throws:

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

binaryValue

public byte[] binaryValue()
                   throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

jsonValue

public java.util.Map<java.lang.String,java.lang.Object> jsonValue()
                                                           throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

jsonValue

public <T> T jsonValue(java.lang.Class<T> c)
                throws java.lang.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:

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

otpObjectToOtpList

public static com.ericsson.otp.erlang.OtpErlangList otpObjectToOtpList(com.ericsson.otp.erlang.OtpErlangObject value)
                                                                throws java.lang.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:

java.lang.ClassCastException - if the conversion fails

listValue

public <T> java.util.List<T> listValue(ErlangValue.ListElementConverter<T> converter)
                                throws java.lang.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:

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

listCollectionValue

public <T> java.util.Collection<T> listCollectionValue(java.lang.Class<? extends java.util.Collection<T>> clazz,
                                                       ErlangValue.ListElementConverter<T> converter)
                                                throws java.lang.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:

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

Since:

3.19

listValue

public java.util.List<ErlangValue> listValue()
                                      throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

listCollectionValue

public java.util.Collection<ErlangValue> listCollectionValue(java.lang.Class<? extends java.util.Collection<ErlangValue>> clazz)
                                                      throws java.lang.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:

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

Since:

3.19

longListValue

public java.util.List<java.lang.Long> longListValue()
                                             throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

See Also:

listValue(ListElementConverter)

doubleListValue

public java.util.List<java.lang.Double> doubleListValue()
                                                 throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

See Also:

listValue(ListElementConverter)

stringListValue

public java.util.List<java.lang.String> stringListValue()
                                                 throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

See Also:

listValue(ListElementConverter)

binaryListValue

public java.util.List<byte[]> binaryListValue()
                                       throws java.lang.ClassCastException

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

Returns:

the converted value

Throws:

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

See Also:

listValue(ListElementConverter)

jsonListValue

public <T> java.util.List<T> jsonListValue(java.lang.Class<T> c)
                                    throws java.lang.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:

java.lang.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 com.ericsson.otp.erlang.OtpErlangObject value()

Gets the original erlang value.

Returns:

the value as reported by erlang

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

compareTo

public int compareTo(ErlangValue o)

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

Specified by:

compareTo in interface java.lang.Comparable<ErlangValue>

Parameters:

o - another erlang value