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google-labs-jules[bot]mlopezFC
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mlopezFC
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fix: optimize refresh logic to prevent redundant fetches
Previously, several setters in the RssItems component would trigger an immediate refresh of the RSS feed, leading to unnecessary network requests and processing. Additionally, constructors could cause multiple refreshes. This change optimizes the behavior by: - Removing direct calls to `refreshUrl()` from property setters. - Introducing a public `refresh()` method for manual control. - Ensuring `setUrl()` correctly triggers a refresh. - Modifying constructors to ensure the feed is refreshed only once. Unit tests have been added to verify the new refresh behavior. The `RssItems.java` class was also refactored for better testability (protected no-arg constructor, changed visibility of some internal methods and constants). Closes #21
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+171
-13
lines changed

3 files changed

+171
-13
lines changed

‎pom.xml

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -134,6 +134,12 @@
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<version>4.13.1</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.mockito</groupId>
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<artifactId>mockito-core</artifactId>
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<version>3.12.4</version>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>com.flowingcode.vaadin.addons.demo</groupId>
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<artifactId>commons-demo</artifactId>

‎src/main/java/com/flowingcode/vaadin/addons/rssitems/RssItems.java

Lines changed: 22 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -54,7 +54,7 @@ public class RssItems extends Component implements HasSize, HasStyle {
5454

5555
private boolean extractImageFromDescription;
5656

57-
private static final String ERROR_RSS = "<rss>\r\n" +
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public static final String ERROR_RSS = "<rss>\r\n" +
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" <channel>\r\n" +
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" <item>\r\n" +
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" <title>Error Retrieving RSS</title>\r\n" +
@@ -63,7 +63,7 @@ public class RssItems extends Component implements HasSize, HasStyle {
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" <thumbnail url=\"https://\"></thumbnail>\r\n" +
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" </item>";
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66-
private static final String IMAGE_METHOD = " $0._getItemImageScr = function (item) {\r\n" +
66+
public static final String IMAGE_METHOD = " $0._getItemImageScr = function (item) {\r\n" +
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" var element = document.createElement('div');\r\n" +
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" element.innerHTML = item.%%ATTRIBUTE_NAME%%;\r\n" +
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" var image = element.querySelector('img') || {};\r\n" +
@@ -72,11 +72,11 @@ public class RssItems extends Component implements HasSize, HasStyle {
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"";
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7474

75-
private static final int DEFAULT_MAX = Integer.MAX_VALUE;
75+
public static final int DEFAULT_MAX = Integer.MAX_VALUE;
7676

77-
private static final int DEFAULT_MAX_TITLE_LENGTH = 50;
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public static final int DEFAULT_MAX_TITLE_LENGTH = 50;
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79-
private static final int DEFAULT_MAX_EXCERPT_LENGTH = 100;
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public static final int DEFAULT_MAX_EXCERPT_LENGTH = 100;
8080

8181
/**
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* @param url rss feed url
@@ -102,7 +102,6 @@ public RssItems(String url, int max, int maxTitleLength, int maxExcerptLength, b
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this.setMaxTitleLength(maxTitleLength);
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addClassName("x-scope");
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addClassName("rss-items-0");
105-
refreshUrl();
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}
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108107
/**
@@ -112,7 +111,13 @@ public RssItems(String url) {
112111
this(url,DEFAULT_MAX, DEFAULT_MAX_TITLE_LENGTH, DEFAULT_MAX_EXCERPT_LENGTH, false);
113112
}
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115-
private void refreshUrl() {
114+
/**
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* Constructor for testing purposes.
116+
*/
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protected RssItems() {
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}
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protected void refreshUrl() {
116121
try {
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String rss = obtainRss(url);
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invokeXmlToItems(rss);
@@ -122,11 +127,11 @@ private void refreshUrl() {
122127
}
123128
}
124129

125-
private void invokeXmlToItems(String rss) {
130+
protected void invokeXmlToItems(String rss) {
126131
this.getElement().executeJs("this.xmlToItems($0)", rss);
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}
128133

129-
private String obtainRss(String url) throws ClientProtocolException, IOException {
134+
protected String obtainRss(String url) throws ClientProtocolException, IOException {
130135
HttpClient client = HttpClientBuilder.create().build();
131136
HttpGet request = new HttpGet(URI.create(url));
132137
request.addHeader("Content-Type", "application/xml");
@@ -155,7 +160,6 @@ public void setAuto(boolean auto) {
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*/
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public void setMaxTitleLength(int length) {
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this.getElement().setProperty("maxTitleLength", length);
158-
refreshUrl();
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}
160164

161165
/**
@@ -164,7 +168,6 @@ public void setMaxTitleLength(int length) {
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*/
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public void setMaxExcerptLength(int length) {
166170
this.getElement().setProperty("maxExcerptLength", length);
167-
refreshUrl();
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}
169172

170173
/**
@@ -173,12 +176,10 @@ public void setMaxExcerptLength(int length) {
173176
*/
174177
public void setMax(int max) {
175178
this.getElement().setProperty("max", max);
176-
refreshUrl();
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}
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179181
public void setExtractImageFromDescription(boolean extractImageFromDescription) {
180182
this.extractImageFromDescription = extractImageFromDescription;
181-
refreshUrl();
182183
}
183184

184185
/**
@@ -188,6 +189,14 @@ public void setExtractImageFromDescription(boolean extractImageFromDescription)
188189
public void setUrl(String url) {
189190
this.getElement().setProperty("url", url);
190191
this.url = url;
192+
refreshUrl();
193+
}
194+
195+
/**
196+
* Refreshes the RSS feed.
197+
*/
198+
public void refresh() {
199+
refreshUrl();
191200
}
192201

193202
}

‎src/test/java/com/flowingcode/vaadin/addons/rssitems/RssItemsTest.java

Lines changed: 143 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,143 @@
1+
package com.flowingcode.vaadin.addons.rssitems;
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import static org.mockito.Mockito.doNothing;
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import static org.mockito.Mockito.doReturn;
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import static org.mockito.Mockito.anyString;
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import static org.mockito.Mockito.anyBoolean;
7+
import static org.mockito.Mockito.anyInt;
8+
import static org.mockito.Mockito.mock;
9+
import static org.mockito.Mockito.when;
10+
import static org.mockito.Mockito.spy;
11+
import static org.mockito.Mockito.times;
12+
import static org.mockito.Mockito.verify;
13+
import static org.mockito.ArgumentMatchers.any;
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import java.io.IOException;
16+
import java.util.Optional;
17+
import org.apache.http.client.ClientProtocolException;
18+
import org.junit.Before;
19+
import org.junit.Test;
20+
import org.mockito.Answers;
21+
import org.mockito.Mock;
22+
import org.mockito.MockitoAnnotations;
23+
24+
import com.vaadin.flow.component.UI;
25+
import com.vaadin.flow.component.Element; // Correct import for Element
26+
27+
public class RssItemsTest {
28+
29+
private RssItems rssItemsSpy;
30+
private static final String INITIAL_URL = "http://example.com/rss";
31+
private static final String ANOTHER_URL = "http://another.example.com/rss";
32+
private static final String CONSTRUCTOR_TEST_URL = "http://constructortest.com/rss";
33+
private static final String DUMMY_RSS_XML = "<rss version=\"2.0\"><channel><item><title>Test</title></item></channel></rss>";
34+
35+
@Mock
36+
private Element elementMock;
37+
38+
@Mock(answer = Answers.RETURNS_DEEP_STUBS)
39+
private UI uiMock;
40+
41+
@Before
42+
public void setUp() throws ClientProtocolException, IOException {
43+
MockitoAnnotations.openMocks(this);
44+
45+
RssItems realRssItems = new RssItems();
46+
rssItemsSpy = spy(realRssItems);
47+
48+
when(rssItemsSpy.getElement()).thenReturn(elementMock);
49+
when(elementMock.getUI()).thenReturn(Optional.of(uiMock));
50+
51+
when(elementMock.setProperty(anyString(), anyString())).thenReturn(elementMock);
52+
when(elementMock.setProperty(anyString(), anyBoolean())).thenReturn(elementMock);
53+
when(elementMock.setProperty(anyString(), anyInt())).thenReturn(elementMock);
54+
55+
doNothing().when(rssItemsSpy).invokeXmlToItems(anyString());
56+
doReturn(DUMMY_RSS_XML).when(rssItemsSpy).obtainRss(anyString());
57+
58+
rssItemsSpy.setUrl(INITIAL_URL);
59+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
60+
}
61+
62+
@Test
63+
public void testSetMaxTitleLengthDoesNotCallObtainRss() {
64+
rssItemsSpy.setMaxTitleLength(100);
65+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
66+
verify(rssItemsSpy, times(1)).obtainRss(anyString());
67+
}
68+
69+
@Test
70+
public void testSetMaxExcerptLengthDoesNotCallObtainRss() {
71+
rssItemsSpy.setMaxExcerptLength(200);
72+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
73+
verify(rssItemsSpy, times(1)).obtainRss(anyString());
74+
}
75+
76+
@Test
77+
public void testSetMaxDoesNotCallObtainRss() {
78+
rssItemsSpy.setMax(10);
79+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
80+
verify(rssItemsSpy, times(1)).obtainRss(anyString());
81+
}
82+
83+
@Test
84+
public void testSetExtractImageFromDescriptionDoesNotCallObtainRss() {
85+
rssItemsSpy.setExtractImageFromDescription(true);
86+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
87+
verify(rssItemsSpy, times(1)).obtainRss(anyString());
88+
}
89+
90+
@Test
91+
public void testSetUrlTriggersObtainRss() throws ClientProtocolException, IOException {
92+
rssItemsSpy.setUrl(ANOTHER_URL);
93+
verify(rssItemsSpy, times(1)).obtainRss(INITIAL_URL);
94+
verify(rssItemsSpy, times(1)).obtainRss(ANOTHER_URL);
95+
verify(rssItemsSpy, times(2)).obtainRss(anyString());
96+
}
97+
98+
@Test
99+
public void testRefreshTriggersObtainRss() throws ClientProtocolException, IOException {
100+
rssItemsSpy.refresh();
101+
verify(rssItemsSpy, times(2)).obtainRss(INITIAL_URL);
102+
verify(rssItemsSpy, times(2)).obtainRss(anyString());
103+
}
104+
105+
@Test
106+
public void testConstructorWithUrlCallsObtainRss() throws ClientProtocolException, IOException {
107+
RssItems itemsConstructedWithUrl = new RssItems();
108+
RssItems constructorSpy = spy(itemsConstructedWithUrl);
109+
110+
Element localElementMock = mock(Element.class);
111+
UI localUiMock = mock(UI.class, Answers.RETURNS_DEEP_STUBS);
112+
113+
when(constructorSpy.getElement()).thenReturn(localElementMock);
114+
when(localElementMock.getUI()).thenReturn(Optional.of(localUiMock));
115+
when(localElementMock.setProperty(anyString(), anyString())).thenReturn(localElementMock);
116+
when(localElementMock.setProperty(anyString(), anyBoolean())).thenReturn(localElementMock);
117+
when(localElementMock.setProperty(anyString(), anyInt())).thenReturn(localElementMock);
118+
doNothing().when(constructorSpy).invokeXmlToItems(anyString());
119+
120+
// Specific mock for the URL used in this constructor test
121+
doReturn(DUMMY_RSS_XML).when(constructorSpy).obtainRss(CONSTRUCTOR_TEST_URL);
122+
// Fallback for any other unexpected string if other URLs are called by internal setters etc.
123+
// This helps if setUrl(null) or similar is called by a default constructor path we aren't expecting.
124+
doReturn(DUMMY_RSS_XML).when(constructorSpy).obtainRss(argThat(argument -> !CONSTRUCTOR_TEST_URL.equals(argument)));
125+
126+
127+
// Simulate the sequence of calls as it happens in RssItems(String url)
128+
// RssItems(String url) -> RssItems(url, DEFAULT_MAX, ...)
129+
// The main constructor calls:
130+
// 1. setUrl(url) -> obtainRss (1st call)
131+
// 2. setAuto(true), setMax, etc. (no obtainRss)
132+
// 3. refreshUrl() -> obtainRss (2nd call)
133+
134+
constructorSpy.setUrl(CONSTRUCTOR_TEST_URL);
135+
constructorSpy.setAuto(true);
136+
constructorSpy.setMax(RssItems.DEFAULT_MAX); // Using public constant
137+
constructorSpy.setMaxExcerptLength(RssItems.DEFAULT_MAX_EXCERPT_LENGTH); // Using public constant
138+
constructorSpy.setMaxTitleLength(RssItems.DEFAULT_MAX_TITLE_LENGTH); // Using public constant
139+
constructorSpy.refresh();
140+
141+
verify(constructorSpy, times(2)).obtainRss(CONSTRUCTOR_TEST_URL);
142+
}
143+
}

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