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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;

import com.rapiddweller.common.converter.ToStringConverter;

import java.lang.reflect.Array;

/**
 * Helper class for building arrays.
 *
 * @param  the component type of the array
 * @author Volker Bergmann
 * @since 0.2.04
 */
public class ArrayBuilder {

  private static final int DEFAULT_INITIAL_CAPACITY = 10;

  private static final Escalator escalator = new LoggerEscalator();

  private final Class componentType;
  private E[] buffer;
  private int elementCount;

  /**
   * Instantiates a new Array builder.
   *
   * @param componentType the component type
   */
  public ArrayBuilder(Class componentType) {
    this(componentType, DEFAULT_INITIAL_CAPACITY);
  }

  /**
   * Instantiates a new Array builder.
   *
   * @param componentType   the component type
   * @param initialCapacity the initial capacity
   */
  public ArrayBuilder(Class componentType, int initialCapacity) {
    this.componentType = componentType;
    this.buffer = createBuffer(initialCapacity);
  }

  /**
   * Append array builder.
   *
   * @param element the element to append
   * @return this array builder
   * @deprecated replaced with add(Element)
   */
  @Deprecated
  public ArrayBuilder append(E element) {
    escalator.escalate(getClass().getName() + ".append() is deprecated, please use the add() method",
        getClass(), null);
    return add(element);
  }

  /**
   * Add array builder.
   *
   * @param element the element
   * @return the array builder
   */
  public ArrayBuilder add(E element) {
    if (buffer == null) {
      throw new UnsupportedOperationException("ArrayBuilder cannot be reused after invoking toArray()");
    }
    if (elementCount >= buffer.length - 1) {
      E[] newBuffer = createBuffer(buffer.length * 2);
      System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
      buffer = newBuffer;
    }
    buffer[elementCount++] = element;
    return this;
  }

  /**
   * Add all if not contained.
   *
   * @param elements the elements
   */
  @SafeVarargs
  public final void addAllIfNotContained(E... elements) {
    for (E element : elements) {
      addIfNotContained(element);
    }
  }

  /**
   * Add if not contained.
   *
   * @param element the element
   */
  public void addIfNotContained(E element) {
    if (!contains(element)) {
      add(element);
    }
  }

  /**
   * Contains boolean.
   *
   * @param element the element
   * @return the boolean
   */
  public boolean contains(E element) {
    for (int i = 0; i < elementCount; i++) {
      if (NullSafeComparator.equals(buffer[i], element)) {
        return true;
      }
    }
    return false;
  }

  /**
   * Add all.
   *
   * @param elements the elements
   */
  public void addAll(E[] elements) {
    for (E element : elements) {
      add(element);
    }
  }

  /**
   * To array e [ ].
   *
   * @return the e [ ]
   */
  public E[] toArray() {
    E[] result = ArrayUtil.newInstance(componentType, elementCount);
    System.arraycopy(buffer, 0, result, 0, elementCount);
    elementCount = 0;
    buffer = null;
    return result;
  }

  /**
   * Size int.
   *
   * @return the int
   */
  public int size() {
    return elementCount;
  }

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < elementCount; i++) {
      if (i > 0) {
        builder.append(", ");
      }
      builder.append(ToStringConverter.convert(buffer[i], "[NULL]"));
    }
    return builder.toString();
  }

  // private helpers -------------------------------------------------------------------------------------------------

  @SuppressWarnings("unchecked")
  private E[] createBuffer(int initialCapacity) {
    return (E[]) Array.newInstance(componentType, initialCapacity);
  }

}