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A set of utilities and tools to speed up and ease programming in Java.
There is a newer version: 0.5
/*
 * (c) 2005 David B. Bracewell
 *
 * 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 com.davidbracewell.conversion;

import com.davidbracewell.collection.PrimitiveArrayList;
import com.davidbracewell.logging.Logger;
import com.google.common.base.Function;
import com.google.common.collect.Lists;

import java.lang.reflect.Array;
import java.util.List;

/**
 * Converts objects to arrays of objects
 *
 * @param  the component type of the array
 * @author David B. Bracewell
 */
public class ArrayConverter implements Function {

  private static final Logger log = Logger.getLogger(ArrayConverter.class);

  private final Class componentType;

  /**
   * Instantiates a new Array converter.
   *
   * @param componentType the component type
   */
  public ArrayConverter(Class componentType) {
    this.componentType = componentType;
  }

  @Override
  public T[] apply(Object o) {
    if (o == null) {
      return null;
    }

    if (o.getClass().isArray() && o.getClass().getComponentType().equals(componentType)) {
      return Cast.as(o);
    }

    if (Character.class.isAssignableFrom(componentType)) {
      char[] chars = PrimitiveArrayConverter.CHAR.apply(o);
      if (chars != null) {
        return Cast.as(new PrimitiveArrayList<>(chars, Character.class).toArray(new Character[chars.length]));
      }
    } else if (Byte.class.isAssignableFrom(componentType)) {
      byte[] bytes = PrimitiveArrayConverter.BYTE.apply(o);
      if (bytes != null) {
        return Cast.as(new PrimitiveArrayList<>(bytes, Byte.class).toArray(new Byte[bytes.length]));
      }
    }

    List list = Lists.newArrayList();
    boolean anyConversionSuccessful = false;
    for (Object component : Convert.convert(o, Iterable.class)) {
      T comp = Convert.convert(component, componentType);
      if (comp != null) {
        anyConversionSuccessful = true;
      }
      list.add(comp);
    }

    if (!anyConversionSuccessful) {
      log.fine("Cannot convert {0} into an array of {1}.", o.getClass(), componentType);
      return null;
    }

    T[] array = Cast.as(Array.newInstance(componentType, list.size()));
    if (array == null) {
      log.fine("Error creating a new array of {0}", componentType);
      return null;
    }

    return list.toArray(array);
  }


}//END OF ArrayConverter