Improved back-and-forth type-casting between Python and Java.

* Added test that rewrites every node property in the demo model.
* Except for 'Selection' types, which can be read, but not written.
* They would have to be modified via the sub-group `selection()`.
* The test is deactivated in client-server mode where it is very slow.
* Added support for 'DoubleRowMatrix' Java types.
* They are mapped to 2d NumPy arrays of `dtype=object`.
* Lists are now explicitly cast to Java string arrays/matrices.
* Fixed handling of empty lists. (#25)
* Return `None` for empty Java strings.
* Return empty dictionary if node has no properties.

mph/node.py

@@ -253,6 +253,8 @@ def property(self, name, value=None):
     def properties(self):
         """Returns names and values of all node properties as a dictionary."""
         java = self.java
+        if not hasattr(java, 'properties'):
+            return {}
         names = sorted(str(name) for name in java.properties())
         return {name: get(java, name) for name in names}
 
@@ -386,14 +388,23 @@ def cast(value):
     elif isinstance(value, Path):
         return JString(str(value))
     elif isinstance(value, (list, tuple)):
-        return value
+        dimension = array(value).ndim
+        if value == [[]]:
+            value = []
+        return JArray(JString, dimension)(value)
     elif isinstance(value, ndarray):
-        if value.dtype.kind == 'i':
-            return JArray(JInt, value.ndim)(value)
+        if value.dtype.kind == 'b':
+            return JArray(JBoolean, value.ndim)(value)
         elif value.dtype.kind == 'f':
             return JArray(JDouble, value.ndim)(value)
-        elif value.dtype.kind == 'b':
-            return JArray(JBoolean, value.ndim)(value)
+        elif value.dtype.kind == 'i':
+            return JArray(JInt, value.ndim)(value)
+        elif value.dtype.kind == 'O':
+            if value.ndim > 2:
+                error = 'Cannot cast object arrays with more than two rows.'
+                logger.error(error)
+                raise TypeError(error)
+            return JArray(JDouble, 2)([row.astype(float) for row in value])
         else:
             error = f'Cannot cast arrays of data type "{value.dtype}".'
             logger.error(error)
@@ -419,6 +430,19 @@ def get(java, name):
         return array(java.getDoubleArray(name))
     elif datatype == 'DoubleMatrix':
         return array([line for line in java.getDoubleMatrix(name)])
+    elif datatype == 'DoubleRowMatrix':
+        value = java.getDoubleMatrix(name)
+        if len(value) == 0:
+            rows = []
+        elif len(value) == 1:
+            rows = [array(value[0])]
+        elif len(value) == 2:
+            rows = [array(value[0]), array(value[1])]
+        else:
+            error = 'Cannot convert double-row matrix with more than two rows.'
+            logger.error(error)
+            raise TypeError(error)
+        return array(rows, dtype=object)
     elif datatype == 'File':
         return Path(str(java.getString(name)))
     elif datatype == 'Int':
@@ -429,15 +453,23 @@ def get(java, name):
         return array([line for line in java.getIntMatrix(name)])
     elif datatype == 'None':
         return None
+    elif datatype == 'Selection':
+        return [str(string) for string in java.getEntryKeys(name)]
     elif datatype == 'String':
-        return str(java.getString(name))
+        value = java.getString(name)
+        return str(value) if value else None
     elif datatype == 'StringArray':
         return [str(string) for string in java.getStringArray(name)]
     elif datatype == 'StringMatrix':
-        return [[str(string) for string in line]
-                for line in java.getStringMatrix(name)]
+        value = java.getStringMatrix(name)
+        if value:
+            return [[str(string) for string in line] for line in value]
+        else:
+            return [[]]
     else:
-        raise TypeError(f'Cannot convert Java data type "{datatype}".')
+        error = f'Cannot convert Java data type "{datatype}".'
+        logger.error(error)
+        raise TypeError(error)
 
 
 ########################################
@@ -489,10 +521,7 @@ def inspect(java):
         print('properties:')
         names = [str(name) for name in java.properties()]
         for name in names:
-            try:
-                value = get(java, name)
-            except TypeError:
-                value = '[?]'
+            value = get(java, name)
             print(f'  {name}: {value}')
 
     # Define a list of common methods to be suppressed in the output.

tests/test_model.py

@@ -8,7 +8,6 @@
 import parent # noqa F401
 import mph
 from pathlib import Path
-from numpy import array, isclose
 from sys import argv
 import logging
 import warnings
@@ -284,68 +283,16 @@ def test_descriptions():
 
 
 def test_property():
-    # Test conversion to and from 'Boolean'.
-    old = model.property('functions/image', 'flipx')
-    model.property('functions/image', 'flipx', False)
-    assert model.property('functions/image', 'flipx') is False
-    model.property('functions/image', 'flipx', old)
-    assert model.property('functions/image', 'flipx') == old
-    # Test conversion to and from 'Double'.
-    old = model.property('functions/image', 'xmin')
-    model.property('functions/image', 'xmin', -10.0)
-    assert isclose(model.property('functions/image', 'xmin'), -10)
-    model.property('functions/image', 'xmin', old)
-    assert isclose(model.property('functions/image', 'xmin'), old)
-    # Test conversion to and from 'DoubleArray'.
-    old = model.property('exports/field', 'outersolnumindices')
-    new = array([1.0, 2.0, 3.0])
-    model.property('exports/field', 'outersolnumindices', new)
-    assert isclose(model.property('exports/field', 'outersolnumindices'),
-                   new).all()
-    model.property('exports/field', 'outersolnumindices', old)
-    assert isclose(model.property('exports/field', 'outersolnumindices'),
-                   old).all()
-    # Test conversion to and from 'File'.
-    old = model.property('functions/image', 'filename')
-    model.property('functions/image', 'filename', Path('new.tif'))
-    assert model.property('functions/image', 'filename') == Path('new.tif')
-    model.property('functions/image', 'filename', old)
-    assert model.property('functions/image', 'filename') == old
-    # Test conversion to and from 'Int'.
-    old = model.property('functions/image', 'refreshcount')
-    model.property('functions/image', 'refreshcount', 1)
-    assert model.property('functions/image', 'refreshcount') == 1
-    model.property('functions/image', 'refreshcount', old)
-    assert model.property('functions/image', 'refreshcount') == old
-    # Test conversion to and from 'IntArray'.
-    old = model.property('plots/evolution', 'solnum')
-    new = array([1, 2, 3])
-    model.property('plots/evolution', 'solnum', new)
-    assert (model.property('plots/evolution', 'solnum') == new).all()
-    model.property('plots/evolution', 'solnum', old)
-    assert (model.property('plots/evolution', 'solnum') == old).all()
-    # Test conversion from 'None'.
-    none = model.property('functions/image', 'exportfilename')
-    assert none is None
-    # Test conversion to and from 'String'.
-    old = model.property('functions/image', 'funcname')
-    model.property('functions/image', 'funcname', 'new')
-    assert model.property('functions/image', 'funcname') == 'new'
-    model.property('functions/image', 'funcname', old)
-    assert model.property('functions/image', 'funcname') == old
-    # Test conversion to and from 'StringArray'.
-    old = model.property('exports/vector', 'descr')
-    model.property('exports/vector', 'descr', ['x', 'y', 'z'])
-    assert model.property('exports/vector', 'descr') == ['x', 'y', 'z']
-    model.property('exports/vector', 'descr', old)
-    assert model.property('exports/vector', 'descr') == old
-    # Test conversion to and from 'StringMatrix'.
-    old = model.property('plots/evolution', 'plotonsecyaxis')
-    new = [['medium 1', 'on', 'ptgr1'], ['medium 2', 'on', 'ptgr2']]
-    model.property('plots/evolution', 'plotonsecyaxis', new)
-    assert model.property('plots/evolution', 'plotonsecyaxis') == new
-    model.property('plots/evolution', 'plotonsecyaxis', old)
-    assert model.property('plots/evolution', 'plotonsecyaxis') == old
+    assert model.property('functions/step', 'funcname') == 'step'
+    model.property('functions/step', 'funcname', 'renamed')
+    assert model.property('functions/step', 'funcname') == 'renamed'
+    model.property('functions/step', 'funcname', 'step')
+    assert model.property('functions/step', 'funcname') == 'step'
+    assert model.property('functions/step', 'from') == 0.0
+    model.property('functions/step', 'from', 0.1)
+    assert model.property('functions/step', 'from') == 0.1
+    model.property('functions/step', 'from', 0.0)
+    assert model.property('functions/step', 'from') == 0.0
 
 
 def test_properties():

tests/test_node.py

@@ -9,6 +9,7 @@
 import mph
 from mph import node
 from mph.node import Node
+from numpy import array, isclose
 from sys import argv
 from pathlib import Path
 import logging
@@ -166,18 +167,95 @@ def test_rename():
     assert not renamed.exists()
 
 
+def test_rewrite(node):
+    java = node.java
+    if hasattr(java, 'properties'):
+        names = [str(name) for name in node.java.properties()]
+    else:
+        names = []
+    for name in names:
+        value = node.property(name)
+        # Changing selections is not (yet) implemented.
+        if node.java.getValueType(name) == 'Selection':
+            continue
+        # Writing "sol" changes certain node names.
+        if name == 'sol':
+            continue
+        node.property(name, value)
+    for child in node:
+        test_rewrite(child)
+
+
 def test_property():
-    node = Node(model, 'functions/step')
-    assert node.property('funcname') == 'step'
-    node.property('funcname', 'renamed')
-    assert node.property('funcname') == 'renamed'
-    node.property('funcname', 'step')
-    assert node.property('funcname') == 'step'
-    assert node.property('from') == 0.0
-    node.property('from', 0.1)
-    assert node.property('from') == 0.1
-    node.property('from', 0.0)
-    assert node.property('from') == 0.0
+    root   = Node(model, '')
+    image  = Node(model, 'functions/image')
+    plot   = Node(model, 'plots/evolution')
+    field  = Node(model, 'exports/field')
+    vector = Node(model, 'exports/vector')
+    # Test conversion to and from 'Boolean'.
+    old = image.property('flipx')
+    image.property('flipx', False)
+    assert image.property('flipx') is False
+    image.property('flipx', old)
+    assert image.property('flipx') == old
+    # Test conversion to and from 'Double'.
+    old = image.property('xmin')
+    image.property('xmin', -10.0)
+    assert isclose(image.property('xmin'), -10)
+    image.property('xmin', old)
+    assert isclose(image.property('xmin'), old)
+    # Test conversion to and from 'DoubleArray'.
+    old = field.property('outersolnumindices')
+    new = array([1.0, 2.0, 3.0])
+    field.property('outersolnumindices', new)
+    assert isclose(field.property('outersolnumindices'), new).all()
+    field.property('outersolnumindices', old)
+    assert isclose(field.property('outersolnumindices'), old).all()
+    # Test conversion to and from 'File'.
+    old = image.property('filename')
+    image.property('filename', Path('new.tif'))
+    assert image.property('filename') == Path('new.tif')
+    image.property('filename', old)
+    assert image.property('filename') == old
+    # Test conversion to and from 'Int'.
+    old = image.property('refreshcount')
+    image.property('refreshcount', 1)
+    assert image.property('refreshcount') == 1
+    image.property('refreshcount', old)
+    assert image.property('refreshcount') == old
+    # Test conversion to and from 'IntArray'.
+    old = plot.property('solnum')
+    new = array([1, 2, 3])
+    plot.property('solnum', new)
+    assert (plot.property('solnum') == new).all()
+    plot.property('solnum', old)
+    assert (plot.property('solnum') == old).all()
+    # Test conversion from 'None'.
+    none = image.property('exportfilename')
+    assert none is None
+    # Test conversion to and from 'String'.
+    old = image.property('funcname')
+    image.property('funcname', 'new')
+    assert image.property('funcname') == 'new'
+    image.property('funcname', old)
+    assert image.property('funcname') == old
+    # Test conversion to and from 'StringArray'.
+    old = vector.property('descr')
+    vector.property('descr', ['x', 'y', 'z'])
+    assert vector.property('descr') == ['x', 'y', 'z']
+    vector.property('descr', old)
+    assert vector.property('descr') == old
+    # Test conversion to and from 'StringMatrix'.
+    old = plot.property('plotonsecyaxis')
+    new = [['medium 1', 'on', 'ptgr1'], ['medium 2', 'on', 'ptgr2']]
+    plot.property('plotonsecyaxis', new)
+    assert plot.property('plotonsecyaxis') == new
+    plot.property('plotonsecyaxis', old)
+    assert plot.property('plotonsecyaxis') == old
+    # Read and write back every node property in the model.
+    if not client.port:
+        # Skip test in client-server mode where it's excruciatingly slow.
+        test_rewrite(root)
 
 
 def test_properties():

tests/test_session.py

@@ -103,9 +103,10 @@ def test_getitem():
 
 
 def test_remove():
-    assert model in client
+    name = model.name()
+    assert name in client.names()
     client.remove(model)
-    assert model not in client
+    assert name not in client.names()
     message = ''
     try:
         model.java.component()