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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * Licensed 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 com.rapiddweller.common.converter;

import com.rapiddweller.common.CollectionUtil;
import com.rapiddweller.common.ConversionException;

import java.util.Arrays;
import java.util.Collection;
import java.util.List;

/**
 * Converts arrays and collections to collections of same content, everything else is converted to a collection of size 1.
 * Created: 26.08.2007 16:16:15
 *
 * @param  the collection type to convert to
 */
@SuppressWarnings({"unchecked", "rawtypes"})
public class ToCollectionConverter extends ThreadSafeConverter {

  /**
   * Instantiates a new To collection converter.
   */
  public ToCollectionConverter() {
    this((Class) List.class);
  }

  /**
   * Instantiates a new To collection converter.
   *
   * @param targetType the target type
   */
  public ToCollectionConverter(Class targetType) {
    super(Object.class, targetType);
  }

  @Override
  public C convert(Object sourceValue) throws ConversionException {
    return (C) convert(sourceValue, targetType);
  }

  /**
   * Convert collection.
   *
   * @param sourceValue the source value
   * @param targetType  the target type
   * @return the collection
   */
  public static Collection convert(Object sourceValue, Class targetType) {
    if (sourceValue == null) {
      return null;
    }
    if (sourceValue.getClass() == targetType) {
      return (Collection) sourceValue;
    }
    Collection collection = CollectionUtil.newInstance(targetType);
    if (sourceValue instanceof Collection) {
      collection.addAll((Collection) sourceValue);
    } else if (sourceValue.getClass().isArray()) {
      Object[] array = (Object[]) sourceValue;
      collection.addAll(Arrays.asList(array));
    } else {
      collection.add(sourceValue);
    }
    return collection;
  }

}