return list != null ? Collections.unmodifiableList(list) : Collections.emptyList();
    }

    private static Map<String, String> unmodifiable(Map<String, String> map) {
        return map != null ? Collections.unmodifiableMap(map) : Collections.emptyMap();
    }

    private static Map<String, String> toMap(Properties properties) {
        if (properties != null && !properties.isEmpty()) {

        final ComponentDef<?> componentDef = prototypeMap.get(name);
        if (componentDef != null) {
            return (T) componentDef.get();
        }
        final ComponentHolder<?> componentHolder = singletonMap.get(name);
        if (componentHolder != null) {
            return (T) componentHolder.get();
        }
        return null;
    }

    @Override
    public boolean available() {
        return available;

            }
        }
        return null;
    }

    protected Integer getAttributeAsInteger(final NamedNodeMap attributes, final String name) {
        final Node namedItem = attributes.getNamedItem(name);
        if (namedItem == null) {
            return null;
        }
        final String value = namedItem.getTextContent();
        if (value == null) {
            return null;
        }
        try {

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    }

    @Test
    void handlesAbsentTransferSource() throws InterruptedException, TransferCancelledException {
        TransferResource resource = new TransferResource(null, null, "http://maven.org/test/test-resource", null, null);

        RepositorySystemSession session = Mockito.mock(RepositorySystemSession.class);
        TransferListener delegate = Mockito.mock(TransferListener.class);

    private TokenStream createTokenStream(final Reader rd) {
        return null;
        /*
         * TODO if (tokenizerFactory instanceof JapaneseTokenizerFactory) { return tokenizerFactory.create(); } else {
         * return null; }
         */
    }

    protected String getReadingFromAttribute(final TokenStream stream) {
        return null;
        /*

            ExtractData data = emlExtractor.getText(in, null);
            final String[] receivedDate = data.getValues("Received-Date");
            logger.info("Received-Date: {}", receivedDate[0]);
            assertEquals(receivedDate[0], "2012-11-11T02:39:59.000Z");
        }
    }

    public void test_getDecodeText() throws Exception {
        assertEquals("", emlExtractor.getDecodeText(null));

    protected void assertObjectNotNull(String variableName, Object value) {
        if (variableName == null) {
            String msg = "The value should not be null: variableName=null value=" + value;
            throw new IllegalArgumentException(msg);
        }
        if (value == null) {
            String msg = "The value should not be null: variableName=" + variableName;
            throw new IllegalArgumentException(msg);
        }

    protected void assertObjectNotNull(String variableName, Object value) {
        if (variableName == null) {
            String msg = "The value should not be null: variableName=null value=" + value;
            throw new IllegalArgumentException(msg);
        }
        if (value == null) {
            String msg = "The value should not be null: variableName=" + variableName;
            throw new IllegalArgumentException(msg);
        }

                            valueClass == null ? null : valueClass.getName(), valueClass == null ? null : valueClass.getClassLoader(),
                            value, targetClass == null ? null : targetClass.getName(),
                            targetClass == null ? null : targetClass.getClassLoader()),
                    e);
        }
    }

    /**
     * インスタンスフィールドかどうか返します。