Don't allocate unnecessary memory for empty array of Objects in

MethodProperty (#10446).

Change-Id: Ib8e2cfb42494a9dd3efb5ca62ddea9675a1dab1e

2 files changed, 162 insertions, 9 deletions

diff --git a/server/src/com/vaadin/data/util/MethodProperty.java b/server/src/com/vaadin/data/util/MethodProperty.java
index 0464d50b62..d7323d872f 100644
--- a/server/src/com/vaadin/data/util/MethodProperty.java
+++ b/server/src/com/vaadin/data/util/MethodProperty.java
@@ -19,6 +19,7 @@ package com.vaadin.data.util;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Arrays;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -85,6 +86,10 @@ public class MethodProperty<T> extends AbstractProperty<T> {
      */
     private transient Class<? extends T> type;
 
+    private static final Object[] DEFAULT_GET_ARGS = new Object[0];
+
+    private static final Object[] DEFAULT_SET_ARGS = new Object[1];
+
     /* Special serialization to handle method references */
     private void writeObject(java.io.ObjectOutputStream out) throws IOException {
         out.defaultWriteObject();
@@ -120,8 +125,9 @@ public class MethodProperty<T> extends AbstractProperty<T> {
             Class<T> class1 = (Class<T>) SerializerHelper.readClass(in);
             type = class1;
             instance = in.readObject();
-            setArgs = (Object[]) in.readObject();
-            getArgs = (Object[]) in.readObject();
+            Object[] setArgs = (Object[]) in.readObject();
+            Object[] getArgs = (Object[]) in.readObject();
+            setArguments(getArgs, setArgs, setArgumentIndex);
             String name = (String) in.readObject();
             Class<?>[] paramTypes = SerializerHelper.readClassArray(in);
             if (name != null) {
@@ -219,7 +225,7 @@ public class MethodProperty<T> extends AbstractProperty<T> {
             type = (Class<T>) returnType;
         }
 
-        setArguments(new Object[] {}, new Object[] { null }, 0);
+        setArguments(DEFAULT_GET_ARGS, DEFAULT_SET_ARGS, 0);
         this.instance = instance;
     }
 
@@ -627,13 +633,15 @@ public class MethodProperty<T> extends AbstractProperty<T> {
      */
     public void setArguments(Object[] getArgs, Object[] setArgs,
             int setArgumentIndex) {
-        this.getArgs = new Object[getArgs.length];
-        for (int i = 0; i < getArgs.length; i++) {
-            this.getArgs[i] = getArgs[i];
+        if (getArgs.length == 0) {
+            this.getArgs = DEFAULT_GET_ARGS;
+        } else {
+            this.getArgs = Arrays.copyOf(getArgs, getArgs.length);
         }
-        this.setArgs = new Object[setArgs.length];
-        for (int i = 0; i < setArgs.length; i++) {
-            this.setArgs[i] = setArgs[i];
+        if (Arrays.equals(setArgs, DEFAULT_SET_ARGS)) {
+            this.setArgs = DEFAULT_SET_ARGS;
+        } else {
+            this.setArgs = Arrays.copyOf(setArgs, setArgs.length);
         }
         this.setArgumentIndex = setArgumentIndex;
     }
diff --git a/server/tests/src/com/vaadin/data/util/MethodPropertyMemoryConsumption.java b/server/tests/src/com/vaadin/data/util/MethodPropertyMemoryConsumption.java
new file mode 100644
index 0000000000..caff33cf50
--- /dev/null
+++ b/server/tests/src/com/vaadin/data/util/MethodPropertyMemoryConsumption.java
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.data.util;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Field;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test for MethodProperty: don't allocate unnecessary Object arrays.
+ * 
+ * @since 7.2
+ * @author Vaadin Ltd
+ */
+public class MethodPropertyMemoryConsumption {
+
+    @Test
+    public void testSetArguments() throws NoSuchFieldException,
+            SecurityException, IllegalArgumentException, IllegalAccessException {
+        TestBean bean = new TestBean();
+        TestMethodProperty<String> property = new TestMethodProperty<String>(
+                bean, "name");
+        Object[] getArgs = property.getGetArgs();
+        Object[] setArgs = property.getSetArgs();
+
+        Field getArgsField = TestMethodProperty.class
+                .getDeclaredField("getArgs");
+        getArgsField.setAccessible(true);
+
+        Field setArgsField = TestMethodProperty.class
+                .getDeclaredField("setArgs");
+        setArgsField.setAccessible(true);
+
+        Assert.assertSame("setArguments method sets non-default instance"
+                + " of empty Object array for getArgs",
+                getArgsField.get(property), getArgs);
+
+        Assert.assertSame("setArguments method sets non-default instance"
+                + " of empty Object array for setArgs",
+                setArgsField.get(property), setArgs);
+    }
+
+    @Test
+    public void testDefaultCtor() {
+        TestBean bean = new TestBean();
+        TestMethodProperty<String> property = new TestMethodProperty<String>(
+                bean, "name");
+
+        Object[] getArgs = property.getGetArgs();
+        Object[] setArgs = property.getSetArgs();
+
+        TestBean otherBean = new TestBean();
+        TestMethodProperty<String> otherProperty = new TestMethodProperty<String>(
+                otherBean, "name");
+        Assert.assertSame("setArguments method uses different instance"
+                + " of empty Object array for getArgs", getArgs,
+                otherProperty.getGetArgs());
+        Assert.assertSame("setArguments method uses different instance"
+                + " of empty Object array for setArgs", setArgs,
+                otherProperty.getSetArgs());
+    }
+
+    @Test
+    public void testDefaultArgsSerialization() throws IOException,
+            ClassNotFoundException {
+        TestBean bean = new TestBean();
+        TestMethodProperty<String> property = new TestMethodProperty<String>(
+                bean, "name");
+
+        ByteArrayOutputStream sourceOutStream = new ByteArrayOutputStream();
+        ObjectOutputStream outStream = new ObjectOutputStream(sourceOutStream);
+        outStream.writeObject(property);
+
+        ObjectInputStream inputStream = new ObjectInputStream(
+                new ByteArrayInputStream(sourceOutStream.toByteArray()));
+        Object red = inputStream.readObject();
+        TestMethodProperty<?> deserialized = (TestMethodProperty<?>) red;
+
+        Assert.assertNotNull("Deseriliation doesn't call setArguments method",
+                deserialized.getGetArgs());
+        Assert.assertNotNull("Deseriliation doesn't call setArguments method",
+                deserialized.getSetArgs());
+
+    }
+
+    public static class TestMethodProperty<T> extends MethodProperty<T> {
+
+        public TestMethodProperty(Object instance, String beanPropertyName) {
+            super(instance, beanPropertyName);
+        }
+
+        @Override
+        public void setArguments(Object[] getArgs, Object[] setArgs,
+                int setArgumentIndex) {
+            super.setArguments(getArgs, setArgs, setArgumentIndex);
+            this.getArgs = getArgs;
+            this.setArgs = setArgs;
+        }
+
+        Object[] getGetArgs() {
+            return getArgs;
+        }
+
+        Object[] getSetArgs() {
+            return setArgs;
+        }
+
+        private transient Object[] getArgs;
+        private transient Object[] setArgs;
+    }
+
+    public static class TestBean implements Serializable {
+
+        private String name;
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+    }
+}