deephaven.jcompat#

This module provides Java compatibility support including convenience functions to create some widely used Java data structures from corresponding Python ones in order to be able to call Java methods.

is_java_type(obj)[source]#

Returns True if the object is originated in Java.

Return type:

bool

j_array_list(values=None)[source]#

Creates a Java ArrayList instance from an iterable.

Return type:

JType

j_binary_operator(func, dtype)[source]#

Constructs a Java ‘Function<PyObject, PyObject, Object>’ implementation from a Python callable or an object with an ‘apply’ method that accepts a single argument.

Parameters:

  • func (Callable) – a Python callable or an object with an ‘apply’ method that accepts two arguments

  • dtype (DType) – the return type of ‘func’

Return type:

JType

Returns:

io.deephaven.integrations.python.PythonFunction instance

j_function(func, dtype)[source]#

Constructs a Java ‘Function<PyObject, Object>’ implementation from a Python callable or an object with an ‘apply’ method that accepts a single argument.

Parameters:

  • func (Callable) – a Python callable or an object with an ‘apply’ method that accepts a single argument

  • dtype (DType) – the return type of ‘func’

Return type:

JType

Returns:

io.deephaven.integrations.python.PythonFunction instance

j_hashmap(d=None)[source]#

Creates a Java HashMap from a dict.

Return type:

JType

j_hashset(s=None)[source]#

Creates a Java HashSet from a set.

Return type:

JType

j_lambda(func, lambda_jtype, return_dtype=None)[source]#

Wraps a Python Callable as a Java “lambda” type.

Java lambda types must contain a single abstract method.

Parameters:

  • func (Callable) – Any Python Callable or object with an ‘apply’ method that accepts the same arguments (number and type) the target Java lambda type

  • lambda_jtype (jpy.JType) – The Java lambda interface to wrap the provided callable in

  • return_dtype (DType) – The expected return type if conversion should be applied. None (the default) does not attempt to convert the return value and returns a Java Object.

j_list_to_list(jlist)[source]#

Converts a java list to a python list.

Return type:

List[Any]

j_map_to_dict(m)[source]#

Converts a java map to a python dictionary.

Return type:

Dict[Any, Any]

j_properties(d=None)[source]#

Creates a Java Properties from a dict.

Return type:

JType

j_runnable(callable)[source]#

Constructs a Java ‘Runnable’ implementation from a Python callable that doesn’t take any arguments and returns None.

Parameters:

callable (Callable[[], None]) – a Python callable that doesn’t take any arguments and returns None

Return type:

JType

Returns:

io.deephaven.integrations.python.PythonRunnable instance

j_unary_operator(func, dtype)[source]#

Constructs a Java ‘Function<PyObject, Object>’ implementation from a Python callable or an object with an ‘apply’ method that accepts a single argument.

Parameters:

  • func (Callable) – a Python callable or an object with an ‘apply’ method that accepts a single argument

  • dtype (DType) – the return type of ‘func’

Return type:

JType

Returns:

io.deephaven.integrations.python.PythonFunction instance

to_sequence(v=None, wrapped=False)[source]#

A convenience function to create a sequence of wrapped or unwrapped object from either one or a sequence of input values to help JPY find the matching Java overloaded method to call.

This also enables a function to provide parameters that can accept both singular and plural values of the same type for the convenience of the users, e.g. both x= “abc” and x = [“abc”] are valid arguments.

Parameters:

  • v (Union[T, Sequence[T]], optional) – the input value(s) to be converted to a sequence

  • wrapped (bool, optional) – if True, the input value(s) will remain wrapped in a JPy object; otherwise, the input value(s) will be unwrapped. Defaults to False.

Returns:

a sequence of wrapped or unwrapped objects

Return type:

Sequence[Union[T, jpy.JType]]