Added an unchecked exception that I find useful for marking code that the developer thinks will not cause an exception.

Added JUnit unit tests for this new exception.
This commit is contained in:
dchandler 2002-09-28 14:38:59 +00:00
parent bd6dc4c329
commit 955c46a7eb
3 changed files with 256 additions and 0 deletions

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/*
The contents of this file are subject to the THDL Open Community License
Version 1.0 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License on the THDL web site
(http://www.thdl.org/).
Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
License for the specific terms governing rights and limitations under the
License.
The Initial Developer of this software is the Tibetan and Himalayan Digital
Library (THDL). Portions created by the THDL are Copyright 2001 THDL.
All Rights Reserved.
Contributor(s): ______________________________________.
*/
package org.thdl.util;
import junit.framework.Test;
import junit.framework.TestSuite;
/**
* @author David Chandler
*
* Runs all JUnit test cases in this package.
*/
public class AllTests {
public static void main(String[] args) {
junit.textui.TestRunner.run(AllTests.class);
}
public static Test suite() {
TestSuite suite = new TestSuite("Test for org.thdl.util");
//$JUnit-BEGIN$
suite.addTest(new TestSuite(ThdlLazyExceptionTest.class));
//$JUnit-END$
return suite;
}
}

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/*
The contents of this file are subject to the THDL Open Community License
Version 1.0 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License on the THDL web site
(http://www.thdl.org/).
Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
License for the specific terms governing rights and limitations under the
License.
The Initial Developer of this software is the Tibetan and Himalayan Digital
Library (THDL). Portions created by the THDL are Copyright 2001 THDL.
All Rights Reserved.
Contributor(s): ______________________________________.
*/
package org.thdl.util;
/**
* @author David Chandler
*
* <p>A ThdlLazyException wraps a "real" java.lang.Exception.
* ThdlLazyException, however, is unchecked. Thus, if you want
* to be a lazy Java programmer, you can use this idiom:</p>
* <pre>
* // Note that bleh does not throw any checked exceptions:
* public static void bleh() {
* try {
* Foo.bar();
* } catch (Throwable t) {
* // Nah, this'll never happen!
* throw new ThdlLazyException(e);
* }
* }
* </pre>
*
* <p>Now your code appears to be well written, and no one but the user
* will ever know the difference.</p>
*
* <p>In Java 1.4 (1.3?), Sun introduced constructors for java.lang.Error that
* allow much the same thing. This code is Java 1 compatible, though, and
* is also a red flag, equivalent to a // FIXME comment.</p>
*/
public final class ThdlLazyException extends Error {
/**
* the wrapped exception
*/
private Throwable wrappedException = null;
/**
* Constructor for ThdlLazyException.
*/
public ThdlLazyException() {
super();
}
/**
* Constructor for ThdlLazyException.
* @param descrip description
*/
public ThdlLazyException(String descrip) {
super(descrip);
}
/**
* Constructor for ThdlLazyException.
* @param descrip description
* @param realException the exception the user should actually care about
*/
public ThdlLazyException(String descrip, Throwable realException) {
super(descrip);
wrappedException = realException;
}
/**
* Constructor for ThdlLazyException.
* @param realException the exception the user should actually care about
*/
public ThdlLazyException(Throwable realException) {
super();
wrappedException = realException;
}
/**
* Returns the wrapped exception, the one about which you should actually
* be concerned.
*/
public Throwable getRealException() {
return wrappedException;
}
}

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/*
The contents of this file are subject to the THDL Open Community License
Version 1.0 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License on the THDL web site
(http://www.thdl.org/).
Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
License for the specific terms governing rights and limitations under the
License.
The Initial Developer of this software is the Tibetan and Himalayan Digital
Library (THDL). Portions created by the THDL are Copyright 2001 THDL.
All Rights Reserved.
Contributor(s): ______________________________________.
*/
package org.thdl.util;
import junit.framework.TestCase;
import java.io.IOException; /* a checked exception */
/**
* @author David Chandler
*
* Tests the ThdlLazyException class.
*/
public class ThdlLazyExceptionTest extends TestCase {
/**
* A helper class that has methods that throw both
* checked and unchecked exceptions.
*/
private class Helper {
Helper() { }
void throwChecked() throws IOException {
throw new java.io.IOException("sure");
}
void saysItThrowsNothing() {
try {
throwChecked();
} catch (IOException e) {
throw new ThdlLazyException(e);
}
}
}
static Helper helper;
protected void setUp() throws Exception {
helper = new Helper();
}
protected void tearDown() throws Exception {
helper = null;
}
/**
* Constructor for ThdlLazyExceptionTest.
* @param arg0
*/
public ThdlLazyExceptionTest(String arg0) {
super(arg0);
}
public static void main(String[] args) {
junit.textui.TestRunner.run(ThdlLazyExceptionTest.class);
}
/*
* Test for void ThdlLazyException()
*/
public void testThdlLazyException() {
Helper x = new Helper();
try {
x.saysItThrowsNothing();
fail("No exception was thrown.");
} catch (ThdlLazyException jle) {
/* good. */
assertTrue(jle.getRealException() instanceof IOException);
} /* don't catch anything else. */
}
/*
* Test for void ThdlLazyException(String)
*/
public void testThdlLazyExceptionString() {
String msg = "foo";
ThdlLazyException e = new ThdlLazyException(msg);
assertTrue(msg.equals(e.getMessage()));
assertTrue(null == e.getRealException());
}
/*
* Test for void ThdlLazyException(String, Throwable)
*/
public void testThdlLazyExceptionStringThrowable() {
String msg = "foo";
IOException ioe = new IOException("bah");
ThdlLazyException e = new ThdlLazyException(msg, ioe);
assertTrue(msg.equals(e.getMessage()));
assertTrue(ioe.equals(e.getRealException()));
assertTrue("bah".equals(e.getRealException().getMessage()));
}
/*
* Test for void ThdlLazyException(Throwable)
*/
public void testThdlLazyExceptionThrowable() {
IOException ioe = new IOException("bah");
ThdlLazyException e = new ThdlLazyException(ioe);
assertTrue(ioe.equals(e.getRealException()));
assertTrue("bah".equals(e.getRealException().getMessage()));
}
public void testGetRealException() {
testThdlLazyExceptionThrowable();
}
}