org.codehaus.jackson.map.util.ArrayBuilders Maven / Gradle / Ivy
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Data Mapper package is a high-performance data binding package
built on Jackson JSON processor
package org.codehaus.jackson.map.util;
import java.lang.reflect.Array;
import java.util.*;
/**
* Helper class that contains set of distinct builders for different
* arrays of primitive values. It also provides trivially simple
* reuse scheme, which assumes that caller knows not to use instances
* concurrently (which works ok with primitive arrays since they can
* not contain other non-primitive types).
*/
public final class ArrayBuilders
{
BooleanBuilder _booleanBuilder = null;
// note: no need for char[] builder, assume they are Strings
ByteBuilder _byteBuilder = null;
ShortBuilder _shortBuilder = null;
IntBuilder _intBuilder = null;
LongBuilder _longBuilder = null;
FloatBuilder _floatBuilder = null;
DoubleBuilder _doubleBuilder = null;
public ArrayBuilders() { }
public BooleanBuilder getBooleanBuilder()
{
if (_booleanBuilder == null) {
_booleanBuilder = new BooleanBuilder();
}
return _booleanBuilder;
}
public ByteBuilder getByteBuilder()
{
if (_byteBuilder == null) {
_byteBuilder = new ByteBuilder();
}
return _byteBuilder;
}
public ShortBuilder getShortBuilder()
{
if (_shortBuilder == null) {
_shortBuilder = new ShortBuilder();
}
return _shortBuilder;
}
public IntBuilder getIntBuilder()
{
if (_intBuilder == null) {
_intBuilder = new IntBuilder();
}
return _intBuilder;
}
public LongBuilder getLongBuilder()
{
if (_longBuilder == null) {
_longBuilder = new LongBuilder();
}
return _longBuilder;
}
public FloatBuilder getFloatBuilder()
{
if (_floatBuilder == null) {
_floatBuilder = new FloatBuilder();
}
return _floatBuilder;
}
public DoubleBuilder getDoubleBuilder()
{
if (_doubleBuilder == null) {
_doubleBuilder = new DoubleBuilder();
}
return _doubleBuilder;
}
/*
/**********************************************************
/* Impl classes
/**********************************************************
*/
public final static class BooleanBuilder
extends PrimitiveArrayBuilder
{
public BooleanBuilder() { }
@Override
public final boolean[] _constructArray(int len) { return new boolean[len]; }
}
public final static class ByteBuilder
extends PrimitiveArrayBuilder
{
public ByteBuilder() { }
@Override
public final byte[] _constructArray(int len) { return new byte[len]; }
}
public final static class ShortBuilder
extends PrimitiveArrayBuilder
{
public ShortBuilder() { }
@Override
public final short[] _constructArray(int len) { return new short[len]; }
}
public final static class IntBuilder
extends PrimitiveArrayBuilder
{
public IntBuilder() { }
@Override
public final int[] _constructArray(int len) { return new int[len]; }
}
public final static class LongBuilder
extends PrimitiveArrayBuilder
{
public LongBuilder() { }
@Override
public final long[] _constructArray(int len) { return new long[len]; }
}
public final static class FloatBuilder
extends PrimitiveArrayBuilder
{
public FloatBuilder() { }
@Override
public final float[] _constructArray(int len) { return new float[len]; }
}
public final static class DoubleBuilder
extends PrimitiveArrayBuilder
{
public DoubleBuilder() { }
@Override
public final double[] _constructArray(int len) { return new double[len]; }
}
/*
/**********************************************************
/* Static helper methods
/**********************************************************
*/
public static HashSet arrayToSet(T[] elements)
{
HashSet result = new HashSet();
if (elements != null) {
for (T elem : elements) {
result.add(elem);
}
}
return result;
}
/**
* Helper method for adding specified element to a List, but also
* considering case where the List may not have been yet constructed
* (that is, null is passed instead).
*
* @param list List to add to; may be null to indicate that a new
* List is to be constructed
* @param element Element to add to list
*
* @return List in which element was added; either list
* (if it was not null), or a newly constructed List.
*/
public static List addToList(List list, T element)
{
if (list == null) {
list = new ArrayList();
}
list.add(element);
return list;
}
/**
* Helper method for constructing a new array that contains specified
* element followed by contents of the given array
*/
public static T[] insertInList(T[] array, T element)
{
int len = array.length;
@SuppressWarnings("unchecked")
T[] result = (T[]) Array.newInstance(array.getClass().getComponentType(), len+1);
if (len > 0) {
System.arraycopy(array, 0, result, 1, len);
}
result[0] = element;
return result;
}
/**
* Helper method for exposing contents of arrays using a read-only
* iterator
*
* @since 1.7
*/
public static Iterator arrayAsIterator(T[] array)
{
return new ArrayIterator(array);
}
public static Iterable arrayAsIterable(T[] array)
{
return new ArrayIterator(array);
}
/*
/**********************************************************
/* Helper classes
/**********************************************************
*/
/**
* Iterator implementation used to efficiently expose contents of an
* Array as read-only iterator.
*
* @since 1.7
*/
private final static class ArrayIterator
implements Iterator, Iterable
{
private final T[] _array;
private int _index;
public ArrayIterator(T[] array) {
_array = array;
_index = 0;
}
@Override public boolean hasNext() {
return _index < _array.length;
}
@Override
public T next()
{
if (_index >= _array.length) {
throw new NoSuchElementException();
}
return _array[_index++];
}
@Override public void remove() {
throw new UnsupportedOperationException();
}
@Override
public Iterator iterator() {
return this;
}
}
}