CloseableUtility.java

package com.kanasansoft.CloseableUtility;

import java.io.Closeable;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class CloseableUtility {

	static public void closeAll(Closeable... closeables) throws IOException {

		closeAll(Arrays.asList(closeables));

	}

	private static 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()));
		}

	}

}

gistfile1.md

Streamを安全にcloseするためのアイディア その1

概要

closeのみを担当するユーティリティメソッド

欠点

• closeのみの対応で、openは関与しない片手落ち状態がオブジェクト指向に反する気がする

Usage.java

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() {

		ByteArrayInputStream is1 = null;
		ByteArrayInputStream is2 = null;
		ByteArrayOutputStream os1 = null;
		ByteArrayOutputStream os2 = null;

		try {

			is1 = new ByteArrayInputStream(new byte[]{});
			is2 = new ByteArrayInputStream(new byte[]{});
			os1 = new ByteArrayOutputStream();
			os2 = new ByteArrayOutputStream();

			//omit

		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				CloseableUtility.closeAll(is1, is2, os1, os2);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

	}

}