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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.array;

import com.rapiddweller.common.converter.ToStringConverter;

/**
 * Helper class for constructing double arrays.
 * Created: 30.12.2013 21:53:43
 *
 * @author Volker Bergmann
 * @since 0.5.26
 */
public class DoubleArrayBuilder {

  private static final int DEFAULT_INITIAL_CAPACITY = 10;

  private double[] buffer;
  private int itemCount;

  /**
   * Instantiates a new Double array builder.
   */
  public DoubleArrayBuilder() {
    this(DEFAULT_INITIAL_CAPACITY);
  }

  /**
   * Instantiates a new Double array builder.
   *
   * @param initialCapacity the initial capacity
   */
  public DoubleArrayBuilder(int initialCapacity) {
    this.buffer = createBuffer(initialCapacity);
  }

  /**
   * Clear.
   */
  public void clear() {
    this.itemCount = 0;
  }

  /**
   * Get double.
   *
   * @param index the index
   * @return the double
   */
  public double get(int index) {
    return buffer[index];
  }

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

  /**
   * Add all.
   *
   * @param elements the elements
   */
  public void addAll(double[] elements) {
    addAll(elements, 0, elements.length);
  }

  /**
   * Add all.
   *
   * @param elements  the elements
   * @param fromIndex the from index
   * @param toIndex   the to index
   */
  public void addAll(double[] elements, int fromIndex, int toIndex) {
    for (int i = fromIndex; i < toIndex; i++) {
      add(elements[i]);
    }
  }

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

  /**
   * To array double [ ].
   *
   * @return the double [ ]
   */
  public double[] toArray() {
    if (buffer == null) {
      throw new UnsupportedOperationException(getClass().getName() + " cannot be reused after invoking toArray()");
    }
    double[] result = new double[itemCount];
    System.arraycopy(buffer, 0, result, 0, itemCount);
    itemCount = 0;
    buffer = null;
    return result;
  }

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


  // private helper method -------------------------------------------------------------------------------------------

  private static double[] createBuffer(int capacity) {
    return new double[capacity];
  }

}