/*
 * 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.configuration2.convert;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

 A specialized implementation of the ListDelimiterHandler interface which disables list splitting. 
 This class does not recognize any list delimiters; passed in strings are returned unchanged. Also the escape() method is a dummy - there is no need for escaping delimiter characters as none are supported. Note that the method for escaping a list throws an UnsupportedOperationException. If list delimiters are not supported, there is no point in squashing multiple values into a single one. 

Implementation note: An instance of this class can be shared between multiple
configuration objects. It is state-less and thread-safe.

Since:
2.0/**
 * <p>
 * A specialized implementation of the {@code ListDelimiterHandler} interface
 * which disables list splitting.
 * </p>
 * <p>
 * This class does not recognize any list delimiters; passed in strings are
 * returned unchanged. Also the {@code escape()} method is a dummy - there is no
 * need for escaping delimiter characters as none are supported. Note that the
 * method for escaping a list throws an {@code UnsupportedOperationException}.
 * If list delimiters are not supported, there is no point in squashing multiple
 * values into a single one.
 * </p>
 * <p>
 * Implementation note: An instance of this class can be shared between multiple
 * configuration objects. It is state-less and thread-safe.
 * </p>
 *
 * @since 2.0
 */
public class DisabledListDelimiterHandler extends AbstractListDelimiterHandler
{
    
A default instance of this class. Because it is safe to share DisabledListDelimiterHandler objects this instance can be used whenever such an object is needed. /**
     * A default instance of this class. Because it is safe to share
     * {@code DisabledListDelimiterHandler} objects this instance can be used
     * whenever such an object is needed.
     */
    public static final ListDelimiterHandler INSTANCE =
            new DisabledListDelimiterHandler();

    
{@inheritDoc} This implementation always throws an UnsupportedOperationException exception. /**
     * {@inheritDoc} This implementation always throws an
     * {@code UnsupportedOperationException} exception.
     */
    @Override
    public Object escapeList(final List<?> values, final ValueTransformer transformer)
    {
        throw new UnsupportedOperationException(
                "Escaping lists is not supported!");
    }

    
{@inheritDoc} This implementation always returns a collection containing the passed in string as its single element. The string is not changed, the trim flag is ignored. (The trim flag refers to the components extracted from the string. Because no components are extracted nothing is trimmed.) /**
     * {@inheritDoc} This implementation always returns a collection containing
     * the passed in string as its single element. The string is not changed,
     * the {@code trim} flag is ignored. (The {@code trim} flag refers to the
     * components extracted from the string. Because no components are extracted
     * nothing is trimmed.)
     */
    @Override
    protected Collection<String> splitString(final String s, final boolean trim)
    {
        final Collection<String> result = new ArrayList<>(1);
        result.add(s);
        return result;
    }

    
{@inheritDoc} This implementation returns the passed in string without
any changes.
/**
     * {@inheritDoc} This implementation returns the passed in string without
     * any changes.
     */
    @Override
    protected String escapeString(final String s)
    {
        return s;
    }
}