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SciJava Common is a shared library for SciJava software. It provides a plugin framework, with an extensible mechanism for service discovery, backed by its own annotation processor, so that plugins can be loaded dynamically. It is used by downstream projects in the SciJava ecosystem, such as ImageJ and SCIFIO.
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package org.scijava.util;
import java.lang.reflect.Array;
import java.util.AbstractList;
/**
* Abstract base class for primitive-type extensible arrays.
*
* This class makes it easy to implement extensible arrays backed by fixed-size
* primitive type arrays, re-allocating and copying data as needed. To avoid
* frequent re-allocation, by default, the fixed-size array will be expanded by
* 50% when running out of space.
*
*
* @author Johannes Schindelin
* @author Curtis Rueden
* @param Type of the primitive array; e.g., {@code double[]}.
* @param Boxed type of the array element; e.g., {@code Double}.
*/
public abstract class AbstractPrimitiveArray extends
AbstractList implements PrimitiveArray
{
/** The class boxing the element type. */
private final Class type;
/**
* The current size of the list.
*
* Note that internally, the actual array length may be greater than this
* value. The size represents the number of actual elements in the collection.
*
*/
private int size;
/** The maximal growth step. */
private int maximumGrowth = Integer.MAX_VALUE;
/**
* Constructs an extensible array of primitive type elements, backed by a
* fixed-size array.
*
* @param type the class of the primitive type
*/
public AbstractPrimitiveArray(final Class type) {
this(type, 0);
}
/**
* Constructs an extensible array of primitive type elements, backed by a
* fixed-size array.
*
* @param type the class of the primitive type
* @param size the initial size
*/
public AbstractPrimitiveArray(final Class type, final int size) {
this.type = type;
this.size = size;
ensureCapacity(size);
}
/**
* Constructs an extensible array of primitive type elements, backed by the
* given fixed-size array.
*
* @param array the array to wrap
* @param type the class of the primitive type
*/
public AbstractPrimitiveArray(final Class type,
final ArrayType array)
{
this.type = type;
setArray(array);
size = capacity();
}
// -- PrimitiveArray methods --
@Override
public int getMaximumGrowth() {
return maximumGrowth;
}
@Override
public void setMaximumGrowth(final int growth) {
if (maximumGrowth < 1) {
throw new IllegalArgumentException("Invalid growth value: " + growth);
}
maximumGrowth = growth;
}
@Override
public ArrayType copyArray() {
return copyArray(size());
}
/** Gets the current capacity of the backing array. */
@Override
public int capacity() {
final ArrayType array = getArray();
return array == null ? 0 : Array.getLength(array);
}
@Override
public void ensureCapacity(final int minCapacity) {
final int oldCapacity = capacity();
if (minCapacity <= oldCapacity) return; // no need to grow
// grow the array by up to 50% (plus a small constant)
final int growth = Math.min(oldCapacity / 2 + 16, maximumGrowth);
final int newCapacity;
if (growth > Integer.MAX_VALUE - oldCapacity) {
// growth would push array over the maximum array size
newCapacity = Integer.MAX_VALUE;
}
else newCapacity = oldCapacity + growth;
// ensure the array grows by at least the requested minimum capacity
final int newLength = Math.max(minCapacity, newCapacity);
// copy the data into a new array
setArray(copyArray(newLength));
}
/**
* Shifts the array to insert space at a specified index.
*
* @param index the index where the space should be inserted
* @param count the number of values to insert
*/
@Override
public void insert(final int index, final int count) {
int oldSize = size();
if (index < 0 || index > oldSize) {
throw new ArrayIndexOutOfBoundsException("Invalid index value");
}
if (count > Integer.MAX_VALUE - oldSize) {
// insertion would push array over the maximum size
throw new IllegalArgumentException("Too many elements");
}
if (count <= 0) {
throw new IllegalArgumentException("Count must be positive");
}
setSize(oldSize + count);
if (index < oldSize) {
final ArrayType array = getArray();
System.arraycopy(array, index, array, index + count, oldSize - index);
}
}
/**
* Shifts the array to delete space starting at a specified index.
*
* @param index the index where the space should be deleted
* @param count the number of values to delete
*/
@Override
public void delete(final int index, final int count) {
int oldSize = size();
if (index < 0 || index > oldSize) {
throw new ArrayIndexOutOfBoundsException("Invalid index value");
}
if (index < 0 || index + count > oldSize) {
throw new IllegalArgumentException("Invalid range: index=" + index +
", count=" + count + ", size=" + oldSize);
}
setSize(oldSize - count);
if (index + count < oldSize) {
final ArrayType array = getArray();
System.arraycopy(array, index + count, array, index, oldSize - index -
count);
}
}
// -- List methods --
// NB: We override and declare abstract to force reimplementation.
@Override
public abstract BaseType set(final int index, final BaseType element);
// NB: We override and declare abstract to force reimplementation.
@Override
public abstract void add(final int index, final BaseType element);
@Override
public BaseType remove(final int index) {
final BaseType removed = get(index);
delete(index, 1);
return removed;
}
// -- Collection methods --
@Override
public int size() {
return size;
}
// NB: Overridden for performance.
@Override
public void clear() {
setSize(0);
}
// -- Sizable methods --
@Override
public void setSize(final int size) {
ensureCapacity(size);
this.size = size;
}
// -- Internal methods --
/** Checks that the index is less than the size of the array. */
protected void checkBounds(final int index) {
if (index >= size()) {
throw new ArrayIndexOutOfBoundsException("Invalid index value");
}
}
// -- Helper methods --
private ArrayType copyArray(final int newLength) {
@SuppressWarnings("unchecked")
final ArrayType copy = (ArrayType) Array.newInstance(type, newLength);
final ArrayType oldArray = getArray();
if (oldArray != null) System.arraycopy(oldArray, 0, copy, 0, size());
return copy;
}
}