code for BAEL-860 - Introduction to mustache (#1885)

mustache/src/main/java/com/baeldung/mustache/MustacheUtil.java

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+package com.baeldung.mustache;
+
+import com.github.mustachejava.DefaultMustacheFactory;
+import com.github.mustachejava.MustacheFactory;
+
+public class MustacheUtil {
+
+    private static final MustacheFactory mf = new DefaultMustacheFactory();
+    
+    public static MustacheFactory getMustacheFactory(){
+        return mf;
+    }
+    
+    
+}

mustache/src/main/java/com/baeldung/mustache/model/Todo.java

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+package com.baeldung.mustache.model;
+
+import java.time.Duration;
+import java.time.temporal.Temporal;
+import java.util.Date;
+import java.util.function.Function;
+
+public class Todo {
+
+    public Todo(){}
+    
+    public Todo(String title, String text){
+        this.title = title;
+        this.text = text;
+        createdOn = new Date();
+    }
+    
+    private String title;
+    private String text;
+    private boolean done = false;
+    
+    private Date createdOn;
+    private Date completedOn;
+    
+    public void markAsDone(){
+        done = true;
+        completedOn = new Date();
+    }
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public boolean getDone() {
+        return done;
+    }
+
+    public Date getCreatedOn() {
+        return createdOn;
+    }
+
+    public Date getCompletedOn() {
+        return completedOn;
+    }
+
+    public void setDone(boolean done) {
+        this.done = done;
+    }
+
+    public void setCompletedOn(Date completedOn) {
+        this.completedOn = completedOn;
+    }
+    
+    public long doneSince(){
+        if ( done ){
+            return Duration.between(createdOn.toInstant(), completedOn.toInstant()).toMinutes();
+        }
+        return 0;
+    }
+    
+    public Function<Object, Object> handleDone(){
+        return (obj) -> {       
+            if ( done ){
+                return String.format("<small>Done %s minutes ago<small>", obj);
+            }else{
+                return "";
+            }
+            
+        };
+        
+    }
+    
+}

mustache/src/main/resources/todo-section.mustache

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+{{#todo}}
+<h2>{{title}}</h2>
+<small>Created on {{createdOn}}</small>
+<p>{{text}}</p>
+{{/todo}}

mustache/src/main/resources/todo.mustache

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+<h2>{{title}}</h2>
+<small>Created on {{createdOn}}</small>
+<p>{{text}}</p>

mustache/src/main/resources/todos-inverted-section.mustache

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+{{#todos}}
+<h2>{{title}}</h2>
+{{/todos}}
+{{^todos}}
+<p>No todos!</p>
+{{/todos}}

mustache/src/main/resources/todos-lambda.mustache

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+{{#todos}}
+<h2>{{title}}{{#handleDone}}{{doneSince}}{{/handleDone}}</h2>
+{{/todos}}

mustache/src/main/resources/todos.mustache

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+{{#todos}}
+<h2>{{title}}</h2>
+{{/todos}}

mustache/src/test/java/com/baeldung/mustache/TodoMustacheServiceTest.java

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+package com.baeldung.mustache;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.temporal.TemporalUnit;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+import org.junit.Test;
+
+import com.baeldung.mustache.model.Todo;
+import com.github.mustachejava.Mustache;
+public class TodoMustacheServiceTest {
+
+    private String executeTemplate(Mustache m, Map<String, Object> context) throws IOException{
+        StringWriter writer = new StringWriter();
+        m.execute(writer, context).flush();
+        return writer.toString();
+    }
+    
+    private String executeTemplate(Mustache m, Todo todo) throws IOException{
+        StringWriter writer = new StringWriter();
+        m.execute(writer, todo).flush();
+        return writer.toString();
+    }
+    
+    @Test
+    public void givenTodoObject_whenGetHtml_thenSuccess() throws IOException{
+        Todo todo = new Todo("Todo 1", "Todo description");
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todo.mustache");
+        Map<String, Object> context = new HashMap<>();
+        context.put("todo", todo);
+        
+        String expected = "<h2>Todo 1</h2>";
+        assertThat(executeTemplate(m, todo)).contains(expected);
+    }
+    
+    @Test
+    public void givenNullTodoObject_whenGetHtml_thenEmptyHtml() throws IOException{
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todo-section.mustache");
+        Map<String, Object> context = new HashMap<>();
+        assertThat(executeTemplate(m, context)).isEmpty();
+    }
+    
+    @Test
+    public void givenTodoList_whenGetHtml_thenSuccess() throws IOException{
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todos.mustache");
+        
+        List<Todo> todos = Arrays.asList(
+            new Todo("Todo 1", "Todo description"),
+            new Todo("Todo 2", "Todo description another"),
+            new Todo("Todo 3", "Todo description another")
+          );
+        Map<String, Object> context = new HashMap<>();
+        context.put("todos", todos);
+        
+        assertThat(executeTemplate(m, context))
+          .contains("<h2>Todo 1</h2>")
+          .contains("<h2>Todo 2</h2>")
+          .contains("<h2>Todo 3</h2>");
+    }
+    
+    @Test
+    public void givenEmptyList_whenGetHtml_thenEmptyHtml() throws IOException{
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todos.mustache");
+        
+        Map<String, Object> context = new HashMap<>();
+        assertThat(executeTemplate(m, context)).isEmpty();;
+    }
+    
+    @Test
+    public void givenEmptyList_whenGetHtmlUsingInvertedSection_thenHtml() throws IOException{
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todos-inverted-section.mustache");
+        
+        Map<String, Object> context = new HashMap<>();
+        assertThat(executeTemplate(m, context).trim()).isEqualTo("<p>No todos!</p>");
+    }
+    
+    @Test
+    public void givenTodoList_whenGetHtmlUsingLamdba_thenHtml() throws IOException{
+        Mustache m = MustacheUtil.getMustacheFactory().compile("todos-lambda.mustache");
+        List<Todo> todos = Arrays.asList(
+            new Todo("Todo 1", "Todo description"),
+            new Todo("Todo 2", "Todo description another"),
+            new Todo("Todo 3", "Todo description another")
+          );
+        todos.get(2).setDone(true);
+        todos.get(2).setCompletedOn(Date.from(Instant.now().plusSeconds(300)));
+        
+        Map<String, Object> context = new HashMap<>();
+        context.put("todos", todos);
+        assertThat(executeTemplate(m, context).trim()).contains("Done 5 minutes ago");
+    }
+}