org.apache.myfaces.util.lang.ArrayUtils Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of myfaces-impl Show documentation
Show all versions of myfaces-impl Show documentation
The private implementation classes of the Apache MyFaces Core JSF-2.3-next Implementation
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.myfaces.util.lang;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.List;
import java.util.RandomAccess;
/**
* Utility class for managing arrays
*/
public class ArrayUtils
{
public static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
public static final String[] EMPTY_STRING_ARRAY = new String[0];
//~ Constructors -------------------------------------------------------------------------------
protected ArrayUtils()
{
// hide from public access
}
//~ Methods ------------------------------------------------------------------------------------
public static Class commonClass(Class c1, Class c2)
{
if (c1 == c2)
{
return c1;
}
if ((c1 == Object.class) || c1.isAssignableFrom(c2))
{
return c1;
}
if (c2.isAssignableFrom(c1))
{
return c2;
}
if (c1.isPrimitive() || c2.isPrimitive())
{
// REVISIT: we could try to autoconvert to Object or something appropriate
throw new IllegalArgumentException("incompatible types " + c1 + " and " + c2);
}
// REVISIT: we could try to find a common supper class or interface
return Object.class;
}
/**
* Concatenates two arrays into one. If arr1 is null or empty, returns arr2.
* If arr2 is null or empty, returns arr1. May return null if both arrays are null,
* or one is empty and the other null.
* The concatenated array has componentType which is compatible with both input arrays (or Object[])
*
* @param arr1 input array
* @param arr2 input array
*
* @return Object the concatenated array, elements of arr1 first
*/
public static Object concat(Object arr1, Object arr2)
{
int len1 = (arr1 == null) ? (-1) : Array.getLength(arr1);
if (len1 <= 0)
{
return arr2;
}
int len2 = (arr2 == null) ? (-1) : Array.getLength(arr2);
if (len2 <= 0)
{
return arr1;
}
Class commonComponentType =
commonClass(arr1.getClass().getComponentType(), arr2.getClass().getComponentType());
Object newArray = Array.newInstance(commonComponentType, len1 + len2);
System.arraycopy(arr1, 0, newArray, 0, len1);
System.arraycopy(arr2, 0, newArray, len1, len2);
return newArray;
}
/**
* Concatenates arrays into one. Any null or empty arrays are ignored.
* If all arrays are null or empty, returns null.
* Elements will be ordered in the order in which the arrays are supplied.
*
* @param arrs array of arrays
* @return the concatenated array
*/
public static Object concat(Object[] arrs)
{
int totalLen = 0;
Class commonComponentType = null;
for (int i = 0, len = arrs.length; i < len; i++)
{
// skip all null arrays
if (arrs[i] == null)
{
continue;
}
int arrayLen = Array.getLength(arrs[i]);
// skip all empty arrays
if (arrayLen == 0)
{
continue;
}
totalLen += arrayLen;
Class componentType = arrs[i].getClass().getComponentType();
commonComponentType =
(commonComponentType == null) ? componentType
: commonClass(commonComponentType, componentType);
}
if (commonComponentType == null)
{
return null;
}
return concat(Array.newInstance(commonComponentType, totalLen), totalLen, arrs);
}
public static Object concat(Object toArray, int totalLen, Object[] arrs)
{
if (totalLen == 0)
{
// Should we allocate an empty array instead?
return toArray;
}
if (totalLen > Array.getLength(toArray))
{
toArray = Array.newInstance(toArray.getClass().getComponentType(), totalLen);
}
for (int i = 0, len = arrs.length, offset = 0; i < len; i++)
{
final Object arr = arrs[i];
if (arr != null)
{
int arrayLen = Array.getLength(arr);
if (arrayLen > 0)
{
System.arraycopy(arr, 0, toArray, offset, arrayLen);
offset += arrayLen;
}
}
}
return toArray;
}
public static Object concat(Object arr1, Object arr2, Object arr3)
{
return concat(new Object[] {arr1, arr2, arr3});
}
public static Object concat(Object arr1, Object arr2, Object arr3, Object arr4)
{
return concat(new Object[] {arr1, arr2, arr3, arr4});
}
public static Object concat(Object arr1, Object arr2, Object arr3, Object arr4, Object arr5)
{
return concat(new Object[] {arr1, arr2, arr3, arr4, arr5});
}
public static Object concatSameType(Object toArray, Object[] arrs)
{
int totalLen = 0;
for (int i = 0, len = arrs.length; i < len; i++)
{
if (arrs[i] != null)
{
totalLen += Array.getLength(arrs[i]);
}
}
return concat(toArray, totalLen, arrs);
}
public static boolean contains(Object[] array, Object value)
{
if (array == null || array.length == 0)
{
return false;
}
for (int i = 0; i < array.length; i++)
{
Object o = array[i];
if ((o == null && value == null) ||
(o != null && o.equals(value)))
{
return true;
}
}
return false;
}
/**
* Same as {@link Collection#addAll(Collection)} but in case of RandomAccess iterates over indices
*/
public static void addAll(Collection collection, Collection toAdd)
{
if (collection == null || toAdd == null)
{
return;
}
if (toAdd instanceof RandomAccess)
{
List randomAccess = (List) toAdd;
for (int i = 0, size = randomAccess.size(); i < size; i++)
{
T element = randomAccess.get(i);
collection.add(element);
}
}
else
{
collection.addAll(toAdd);
}
}
// public static void main(String[] args)
// {
// // test code
// System.out.println(concat(new String[] {"a"}, new Object[] {"b"}));
// System.out.println(concat(new String[] {"a"}, new Integer[] {new Integer(0)}));
// System.out.println(concat(new Number[] {new Double(0)}, new Integer[] {new Integer(0)}));
// System.out.println(concat(new Number[] {}, new Integer[0]));
// System.out.println(concat(new Integer[] {new Integer(0)}, new Number[0]));
// System.out.println(concat(new Integer[] {new Integer(0)}, new Number[0], new int[0]));
// System.out.println(
// concat(new Integer[] {new Integer(0)}, new Number[] {new Double(0)}, new int[0]));
// System.out.println(concat(new int[] {1}, new int[] {2}));
// System.out.println(
// concat(new String[] {"a"}, new Integer[] {new Integer(0)}, new Object[] {"b"}));
// System.out.println(
// concat(new String[0], new Object[] {new String[] {"a"}, new Object[] {"b"}}));
// System.out.println(
// concat(new Integer[] {new Integer(0)}, new Number[] {new Double(0)}, new int[] {1}));
// }
}