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Commons Math example source code file (MathExceptionTest.java)

This example Commons Math source code file (MathExceptionTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Math tags/keywords

bytearrayoutputstream, bytearrayoutputstream, caused, exception, io, mathconfigurationexception, mathexception, mathexception, object, printstream, printstream, printwriter, string, string, testcase, util

The Commons Math MathExceptionTest.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.math;

import junit.framework.TestCase;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.Locale;

/**
 * @version $Revision: 822850 $ $Date: 2009-10-07 14:56:42 -0400 (Wed, 07 Oct 2009) $
 */
public class MathExceptionTest extends TestCase {

    public void testConstructor(){
        MathException ex = new MathException();
        assertNull(ex.getCause());
        assertEquals("", ex.getMessage());
        assertEquals("", ex.getMessage(Locale.FRENCH));
    }

    public void testConstructorPatternArguments(){
        String pattern = "a {0}x{1} matrix cannot be a rotation matrix";
        Object[] arguments = { Integer.valueOf(6), Integer.valueOf(4) };
        MathException ex = new MathException(pattern, arguments);
        assertNull(ex.getCause());
        assertEquals(pattern, ex.getPattern());
        assertEquals(arguments.length, ex.getArguments().length);
        for (int i = 0; i < arguments.length; ++i) {
            assertEquals(arguments[i], ex.getArguments()[i]);
        }
        assertFalse(pattern.equals(ex.getMessage()));
        assertFalse(ex.getMessage().equals(ex.getMessage(Locale.FRENCH)));
    }

    public void testConstructorCause(){
        String inMsg = "inner message";
        Exception cause = new Exception(inMsg);
        MathException ex = new MathException(cause);
        assertEquals(cause, ex.getCause());
    }

    public void testConstructorPatternArgumentsCause(){
        String pattern = "a {0}x{1} matrix cannot be a rotation matrix";
        Object[] arguments = { Integer.valueOf(6), Integer.valueOf(4) };
        String inMsg = "inner message";
        Exception cause = new Exception(inMsg);
        MathException ex = new MathException(cause, pattern, arguments);
        assertEquals(cause, ex.getCause());
        assertEquals(pattern, ex.getPattern());
        assertEquals(arguments.length, ex.getArguments().length);
        for (int i = 0; i < arguments.length; ++i) {
            assertEquals(arguments[i], ex.getArguments()[i]);
        }
        assertFalse(pattern.equals(ex.getMessage()));
        assertFalse(ex.getMessage().equals(ex.getMessage(Locale.FRENCH)));
    }

    /**
     * Tests the printStackTrace() operation.
     */
    public void testPrintStackTrace() {
        String outMsg = "outer message";
        String inMsg = "inner message";
        MathException cause = new MathConfigurationException(inMsg);
        MathException ex = new MathException(cause, outMsg);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PrintStream ps = new PrintStream(baos);
        ex.printStackTrace(ps);
        String stack = baos.toString();
        String outerMsg = "org.apache.commons.math.MathException: outer message";
        String innerMsg = "Caused by: " +
        "org.apache.commons.math.MathConfigurationException: inner message";
        assertTrue(stack.startsWith(outerMsg));
        assertTrue(stack.indexOf(innerMsg) > 0);

        PrintWriter pw = new PrintWriter(ps, true);
        ex.printStackTrace(pw);
        stack = baos.toString();
        assertTrue(stack.startsWith(outerMsg));
        assertTrue(stack.indexOf(innerMsg) > 0);
    }

    /**
     * Test serialization
     */
    public void testSerialization() {
        String outMsg = "outer message";
        String inMsg = "inner message";
        MathException cause = new MathConfigurationException(inMsg);
        MathException ex = new MathException(cause, outMsg);
        MathException image = (MathException) TestUtils.serializeAndRecover(ex);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PrintStream ps = new PrintStream(baos);
        ex.printStackTrace(ps);
        String stack = baos.toString();

        ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
        PrintStream ps2 = new PrintStream(baos2);
        image.printStackTrace(ps2);
        String stack2 = baos2.toString();

        // See if JDK supports nested exceptions.  If not, stack trace of
        // inner exception will not be serialized
        boolean jdkSupportsNesting = false;
        try {
            Throwable.class.getDeclaredMethod("getCause", new Class[0]);
            jdkSupportsNesting = true;
        } catch (NoSuchMethodException e) {
            jdkSupportsNesting = false;
        }

        if (jdkSupportsNesting) {
            assertEquals(stack, stack2);
        } else {
            assertTrue(stack2.indexOf(inMsg) != -1);
            assertTrue(stack2.indexOf("MathConfigurationException") != -1);
        }
    }
}

Other Commons Math examples (source code examples)

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