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'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* 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 org.databene.commons.array;
import org.databene.commons.converter.ToStringConverter;
/**
* Helper class for constructing double arrays.
* Created: 30.12.2013 21:53:43
* @since 0.5.26
* @author Volker Bergmann
*/
public class DoubleArrayBuilder {
private static final int DEFAULT_INITIAL_CAPACITY = 10;
private double[] buffer;
private int itemCount;
public DoubleArrayBuilder() {
this(DEFAULT_INITIAL_CAPACITY);
}
public DoubleArrayBuilder(int initialCapacity) {
this.buffer = createBuffer(initialCapacity);
}
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;
}
public void addAll(double[] elements) {
addAll(elements, 0, elements.length);
}
public void addAll(double[] elements, int fromIndex, int toIndex) {
for (int i = fromIndex; i < toIndex; i++)
add(elements[i]);
}
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];
}
}