design patterns : template

design-pattern/gof/number.txt

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+1
+2
+3
+4
+5

design-pattern/gof/src/template/after/template_callback/Client.java

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+package template.after.template_callback;
+
+public class Client {
+
+    public static void main(String[] args) {
+        FileProcessor fileProcessor = new FileProcessor("number.txt");
+        int result = fileProcessor.process(Integer::sum);
+        System.out.println(result);
+    }
+}

design-pattern/gof/src/template/after/template_callback/FileProcessor.java

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+package template.after.template_callback;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class FileProcessor {
+
+    private String path;
+    public FileProcessor(String path) {
+        this.path = path;
+    }
+
+    public int process(Operator operator) {
+        try(BufferedReader reader = new BufferedReader(new FileReader(path))) {
+            int result = 0;
+            String line = null;
+            while((line = reader.readLine()) != null) {
+                result = operator.getResult(result, Integer.parseInt(line));
+            }
+            return result;
+        } catch (IOException e) {
+            throw new IllegalArgumentException(path + "에 해당하는 파일이 없습니다.", e);
+        }
+    }
+}

design-pattern/gof/src/template/after/template_callback/Operator.java

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+package template.after.template_callback;
+
+public interface Operator {
+
+     int getResult(int result, int line);
+}

design-pattern/gof/src/template/after/template_method/Client.java

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+package template.after.template_method;
+
+public class Client {
+
+    public static void main(String[] args) {
+        FileProcessor fileProcessor = new Plus("number.txt");
+        System.out.println(fileProcessor.process());
+
+        fileProcessor = new Multiply("number.txt");
+        System.out.println(fileProcessor.process());
+    }
+}

design-pattern/gof/src/template/after/template_method/FileProcessor.java

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+package template.after.template_method;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public abstract class FileProcessor {
+
+    private String path;
+    public FileProcessor(String path) {
+        this.path = path;
+    }
+
+    public int process() {
+        try(BufferedReader reader = new BufferedReader(new FileReader(path))) {
+            int result = 0;
+            String line = null;
+            while((line = reader.readLine()) != null) {
+                result = getResult(result, Integer.parseInt(line));
+            }
+            return result;
+        } catch (IOException e) {
+            throw new IllegalArgumentException(path + "에 해당하는 파일이 없습니다.", e);
+        }
+    }
+
+    protected abstract int getResult(int result, int line);
+}

design-pattern/gof/src/template/after/template_method/Multiply.java

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+package template.after.template_method;
+
+public class Multiply extends FileProcessor {
+
+    public Multiply(String path) {
+        super(path);
+    }
+
+    @Override
+    protected int getResult(int result, int line) {
+        return result * line;
+    }
+}

design-pattern/gof/src/template/after/template_method/Plus.java

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+package template.after.template_method;
+
+import template.after.template_method.FileProcessor;
+
+public class Plus extends FileProcessor {
+
+    public Plus(String path) {
+        super(path);
+    }
+
+    @Override
+    protected int getResult(int result, int line) {
+        return result + line;
+    }
+}

design-pattern/gof/src/template/before/Client.java

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+package template.before;
+
+public class Client {
+
+    public static void main(String[] args) {
+        FileProcessor fileProcessor = new FileProcessor("number.txt");
+        int result = fileProcessor.process();
+        System.out.println(result);
+    }
+}

design-pattern/gof/src/template/before/FileProcessor.java

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+package template.before;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class FileProcessor {
+
+    private String path;
+    public FileProcessor(String path) {
+        this.path = path;
+    }
+
+    public int process() {
+        try(BufferedReader reader = new BufferedReader(new FileReader(path))) {
+            int result = 0;
+            String line = null;
+            while((line = reader.readLine()) != null) {
+                result += Integer.parseInt(line);
+            }
+            return result;
+        } catch (IOException e) {
+            throw new IllegalArgumentException(path + "에 해당하는 파일이 없습니다.", e);
+        }
+    }
+}

design-pattern/gof/src/template/before/MultiplyFileProcessor.java

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+package template.before;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class MultiplyFileProcessor {
+
+    private String path;
+    public MultiplyFileProcessor(String path) {
+        this.path = path;
+    }
+
+    public int process() {
+        try(BufferedReader reader = new BufferedReader(new FileReader(path))) {
+            int result = 0;
+            String line = null;
+            while((line = reader.readLine()) != null) {
+                result *= Integer.parseInt(line);
+            }
+            return result;
+        } catch (IOException e) {
+            throw new IllegalArgumentException(path + "에 해당하는 파일이 없습니다.", e);
+        }
+    }
+}