UncheckedIOExceptionクラスは非チェック例外のIO例外で，Java8から導入されたようだ。IOExceptionはチェック例外であるため，IOExceptionがスローされるメソッドにはthrowsをつけて宣言するか，内部でcatchする必要がある。これを回避できるようにしたものが，このUncheckedIOExceptionクラスで，非チェック例外であるRuntimeExceptionクラスを継承している。
コンストラクタは次の２つがオーバーロードされており，いずれも引数にIOExceptionをとる。しかも，内部でObjects.requireNonNull(cause)が呼ばれているため，nullを渡すことも許されない。従って，IOExceptionクラスのインスタンスがないと，UncheckedIOExceptionクラスのインスタンスを作ることができない。IOExceptionをラップして非チェック例外にするためのラッパークラスと言える。
- UncheckedIOException(String message, IOException cause)
- UncheckedIOException(IOException cause)
/*
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
import java.util.Objects;
public class UncheckedIOException extends RuntimeException {
private static final long serialVersionUID = -8134305061645241065L;
public UncheckedIOException(String message, IOException cause) {
super(message, Objects.requireNonNull(cause));
}
public UncheckedIOException(IOException cause) {
super(Objects.requireNonNull(cause));
}
@Override
public IOException getCause() {
return (IOException) super.getCause();
}
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException
{
s.defaultReadObject();
Throwable cause = super.getCause();
if (!(cause instanceof IOException))
throw new InvalidObjectException("Cause must be an IOException");
}
}
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
import java.util.Objects;
public class UncheckedIOException extends RuntimeException {
private static final long serialVersionUID = -8134305061645241065L;
public UncheckedIOException(String message, IOException cause) {
super(message, Objects.requireNonNull(cause));
}
public UncheckedIOException(IOException cause) {
super(Objects.requireNonNull(cause));
}
@Override
public IOException getCause() {
return (IOException) super.getCause();
}
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException
{
s.defaultReadObject();
Throwable cause = super.getCause();
if (!(cause instanceof IOException))
throw new InvalidObjectException("Cause must be an IOException");
}
}
ＪＹ情報システムズ 