mainメソッドからエンクロージングクラスの変数を参照する
- 変数を参照する場合、finalが強要される
- エンクロージングクラスのフィールドならOK
- 実行順を強制できる以外は、利便性はその1とあまり変わらない
- その1よりも複雑なため利点が薄れる
Created
February 24, 2012 18:11
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| package com.kanasansoft.CloseableUtility; | |
| import java.io.Closeable; | |
| import java.io.IOException; | |
| import java.util.Arrays; | |
| import java.util.List; | |
| public abstract class CloseableUtility { | |
| public CloseableUtility(Closeable... closeables) throws IOException { | |
| main(); | |
| closeAll(closeables); | |
| } | |
| abstract public void main() throws IOException; | |
| private void closeAll(Closeable... closeables) throws IOException { | |
| closeAll(Arrays.asList(closeables)); | |
| } | |
| private void closeAll(List<Closeable> closeables) throws IOException { | |
| if (closeables.isEmpty()) { | |
| return; | |
| } | |
| try { | |
| if (closeables.get(0) != null) { | |
| closeables.get(0).close(); | |
| } | |
| } catch (IOException e) { | |
| throw e; | |
| } finally { | |
| closeAll(closeables.subList(1, closeables.size())); | |
| } | |
| } | |
| } |
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| import java.io.ByteArrayInputStream; | |
| import java.io.ByteArrayOutputStream; | |
| import java.io.IOException; | |
| import com.kanasansoft.CloseableUtility.CloseableUtility; | |
| public class Usage { | |
| public static void main(String[] args) { | |
| new Usage(); | |
| } | |
| public Usage() { | |
| final ByteArrayInputStream is1 = new ByteArrayInputStream(new byte[]{}); | |
| final ByteArrayInputStream is2 = new ByteArrayInputStream(new byte[]{}); | |
| final ByteArrayOutputStream os1 = new ByteArrayOutputStream(); | |
| final ByteArrayOutputStream os2 = new ByteArrayOutputStream(); | |
| try { | |
| new CloseableUtility(is1, is2, os1, os2){ | |
| @Override | |
| public void main() throws IOException { | |
| //ex. | |
| //is1.read(); | |
| //is2.read(); | |
| //os1.write(new byte[]{}); | |
| //os2.write(new byte[]{}); | |
| } | |
| }; | |
| } catch (IOException e) { | |
| e.printStackTrace(); | |
| } | |
| } | |
| } |
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