From 63b200e8d4a05d5b744d437fd10781c6b5429da9 Mon Sep 17 00:00:00 2001
From: "wm624@hotmail.com" <wm624@hotmail.com>
Date: Mon, 28 Mar 2016 22:33:25 -0700
Subject: [PATCH] [SPARK-14071][PYSPARK][ML] Change MLWritable.write to be a
 property

Add property to MLWritable.write method, so we can use .write instead of .write()

Add a new test to ml/test.py to check whether the write is a property.
./python/run-tests --python-executables=python2.7 --modules=pyspark-ml

Will test against the following Python executables: ['python2.7']
Will test the following Python modules: ['pyspark-ml']
Finished test(python2.7): pyspark.ml.evaluation (11s)
Finished test(python2.7): pyspark.ml.clustering (16s)
Finished test(python2.7): pyspark.ml.classification (24s)
Finished test(python2.7): pyspark.ml.recommendation (24s)
Finished test(python2.7): pyspark.ml.feature (39s)
Finished test(python2.7): pyspark.ml.regression (26s)
Finished test(python2.7): pyspark.ml.tuning (15s)
Finished test(python2.7): pyspark.ml.tests (30s)
Tests passed in 55 seconds

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #11945 from wangmiao1981/fix_property.
---
 python/pyspark/ml/tests.py | 5 +++++
 python/pyspark/ml/util.py  | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/python/pyspark/ml/tests.py b/python/pyspark/ml/tests.py
index 224232ed7f..f6159b2c95 100644
--- a/python/pyspark/ml/tests.py
+++ b/python/pyspark/ml/tests.py
@@ -51,6 +51,7 @@ from pyspark.ml.param.shared import HasMaxIter, HasInputCol, HasSeed
 from pyspark.ml.regression import LinearRegression, DecisionTreeRegressor
 from pyspark.ml.tuning import *
 from pyspark.ml.util import keyword_only
+from pyspark.ml.util import MLWritable, MLWriter
 from pyspark.ml.wrapper import JavaWrapper
 from pyspark.mllib.linalg import DenseVector, SparseVector
 from pyspark.sql import DataFrame, SQLContext, Row
@@ -655,6 +656,10 @@ class PersistenceTest(PySparkTestCase):
             except OSError:
                 pass
 
+    def test_write_property(self):
+        lr = LinearRegression(maxIter=1)
+        self.assertTrue(isinstance(lr.write, MLWriter))
+
     def test_decisiontree_classifier(self):
         dt = DecisionTreeClassifier(maxDepth=1)
         path = tempfile.mkdtemp()
diff --git a/python/pyspark/ml/util.py b/python/pyspark/ml/util.py
index 6703851262..d4411fdfb9 100644
--- a/python/pyspark/ml/util.py
+++ b/python/pyspark/ml/util.py
@@ -134,13 +134,14 @@ class MLWritable(object):
     .. versionadded:: 2.0.0
     """
 
+    @property
     def write(self):
         """Returns an JavaMLWriter instance for this ML instance."""
         raise NotImplementedError("MLWritable is not yet implemented for type: %r" % type(self))
 
     def save(self, path):
         """Save this ML instance to the given path, a shortcut of `write().save(path)`."""
-        self.write().save(path)
+        self.write.save(path)
 
 
 @inherit_doc
@@ -149,6 +150,7 @@ class JavaMLWritable(MLWritable):
     (Private) Mixin for ML instances that provide :py:class:`JavaMLWriter`.
     """
 
+    @property
     def write(self):
         """Returns an JavaMLWriter instance for this ML instance."""
         return JavaMLWriter(self)
-- 
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