package org.apidesign.delegatingwriter;

import java.io.BufferedWriter;

import java.io.IOException;

import java.io.StringWriter;

import org.junit.Before;

import org.junit.Test;

import static org.junit.Assert.*;

/**

 *

 * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 */

public class BufferedWriterThrowingExceptionTest {

    private StringWriter writer;

    public BufferedWriterThrowingExceptionTest() {

    }

    @Before

    public void setUp() {

        writer = new StringWriter();

    }

    @Test

    public void testBehaviourOfRealBufferInJDK() throws IOException {

        BufferedWriter bufferedWriter = new BufferedWriter(writer);

        doAppendHello(bufferedWriter, "Hello!");

        bufferedWriter.flush();

        assertEquals("Hello!", writer.toString());

    }

    @Test

    public void testBehaviourOfBufferThatThrowsExceptionWhenAppendIsCalled() throws IOException {

        BufferedWriter bufferedWriter = new AltBufferedWriter(writer, AltBufferedWriter.Behaviour.THROW_EXCEPTION);

        doAppendHello(bufferedWriter, "Hello!");

        bufferedWriter.flush();

        assertEquals("Hello!", writer.toString());

    }

    @Test

    public void testBehaviourWhenDelegatingConditionallyIsOK() throws IOException {

        BufferedWriter bufferedWriter = new AltBufferedWriter(writer, AltBufferedWriter.Behaviour.DELEGATE_CONDITIONALLY);

        doAppendHello(bufferedWriter, "Hello!");

        bufferedWriter.flush();

        assertEquals("Hello!", writer.toString());

    }

    private void doAppendHello(BufferedWriter bufferedWriter, CharSequence what) throws IOException {

        // BEGIN: writer.throw.client

        try {

            bufferedWriter.append(what);

        } catch (UnsupportedOperationException ex) {

            bufferedWriter.write(what.toString());

        }

        // END: writer.throw.client

    }

}