init

combinator/README.md

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+---
+layout: pattern
+title: Combinator
+folder: combinator
+permalink: /patterns/combinator/
+categories: Behavioral
+tags:
+ - Functional
+ - Reactive
+ - Idiom
+---
+
+## Also known as
+Composition pattern
+
+## Intent
+The functional pattern representing a style of organizing libraries centered around the idea of combining functions.  
+Putting it simply, there is some type T, some functions for constructing "primitive" values of type T, 
+and some "combinators" which can combine values of type T in various ways to build up more complex values of type T.
+
+
+## Applicability
+Use the combinator pattern when:
+- You are able to create a more complex value from more plain values but having the same type(a combination of them)
+
+
+## Credits
+- [Example for java](https://gtrefs.github.io/code/combinator-pattern/)
+- [Combinator pattern](https://wiki.haskell.org/Combinator_pattern)
+- [Combinatory logic](https://wiki.haskell.org/Combinatory_logic)

combinator/pom.xml

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+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.23.0-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>combinator</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+</project>

combinator/src/main/java/com/iluwatar/combinator/Finder.java

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+package com.iluwatar.combinator;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public interface Finder {
+
+  List<String> find(String text);
+
+
+  static Finder contains(String word) {
+    return txt -> Stream.of(txt.split("\n")).filter(line -> line.contains(word)).collect(Collectors.toList());
+  }
+
+  static Finder exact(String line) {
+    return txt -> Stream.of(txt.split("\n")).filter(in -> in.equals(line)).collect(Collectors.toList());
+  }
+
+  default Finder not(Finder notFinder) {
+    return txt -> {
+      List<String> res = this.find(txt);
+      res.removeAll(notFinder.find(txt));
+      return res;
+    };
+  }
+
+  default Finder or(Finder orFinder) {
+    return txt -> {
+      List<String> res = this.find(txt);
+      res.addAll(orFinder.find(txt));
+      return res;
+    };
+  }
+
+  default Finder and(Finder andFinder) {
+    return
+        txt ->
+            this
+                .find(txt)
+                .stream()
+                .flatMap(line -> andFinder.find(line).stream())
+                .collect(Collectors.toList());
+  }
+
+}

combinator/src/main/java/com/iluwatar/combinator/Finders.java

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+package com.iluwatar.combinator;
+
+import java.util.List;
+
+public class Finders {
+  private Finders() {
+  }
+
+  public static List<String> findOneOf
+}

combinator/src/test/java/com/iluwatar/combinator/FinderTest.java

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+package com.iluwatar.combinator;
+
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class FinderTest {
+
+  @Test
+  public void contains() {
+    String example =
+        "the first one \n"
+            + "the second one \n"
+            + "the second one \n"
+            + "the thrid one \n";
+
+    List<String> result = Finder.contains("second").find(example);
+    System.out.println("");
+  }
+
+  @Test
+  public void exact() {
+  }
+
+  @Test
+  public void not() {
+  }
+
+  @Test
+  public void or() {
+  }
+
+  @Test
+  public void and() {
+  }
+}

pom.xml

@@ -188,6 +188,7 @@
         <module>double-buffer</module>
         <module>sharding</module>
         <module>game-loop</module>
+		<module>combinator</module>
     </modules>
 
     <repositories>