jlibs.core.lang.ArrayUtil Maven / Gradle / Ivy
/**
* Copyright 2015 Santhosh Kumar Tekuri
*
* The JLibs authors license 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 jlibs.core.lang;
import jlibs.core.graph.Filter;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* @author Santhosh Kumar T
*/
public class ArrayUtil{
/*-------------------------------------------------[ Finding Item ]---------------------------------------------------*/
/**
* returns first index of item in given array starting
* from fromIndex(inclusive)
*
* @param array object array, can be null
* @param item item to be searched, can be null
* @param fromIndex index(inclusive) from which search happens.
* @return -1 if array is null, or the item is not found
* otherwize returns first index of item in array
*/
public static int indexOf(T array[], S item, int fromIndex){
if(array==null)
return -1;
for(int i=fromIndex; i int indexOf(T array[], S item){
return indexOf(array, item, 0);
}
/**
* tells whether the array contains the given item
*
* @param array object array, can be null
* @param item item to be searched, can be null
* @return false if array is null, or item is not found
* otherwize returns true;
*/
public static boolean contains(T array[], S item){
return indexOf(array, item)!=-1;
}
/*-------------------------------------------------[ Boundary Items ]---------------------------------------------------*/
/**
* Returns first element in given {@code array}.
*
* if {@code array} is null or of length zero, then returns {@code null}
*/
public static T getFirst(T array[]){
return array!=null && array.length>0 ? array[0] : null;
}
/**
* Returns last element in given {@code array}.
*
* if {@code array} is null or of length zero, then returns {@code null}
*/
public static T getLast(T array[]){
return array!=null && array.length>0 ? array[array.length-1] : null;
}
/*-------------------------------------------------[ Contents Equality ]---------------------------------------------------*/
/**
* returns array1[from1, from1+length-1] and array2[from2, from2+length-1] contain same elements
* in case of index out of range, returns false
*/
public static boolean equals(Object array1[], int from1, Object array2[], int from2, int length){
if(from1array1.length)
return false;
if(from2array2.length)
return false;
for(int i=0; iarray1
starts with array2 */
public static boolean startsWith(Object array1[], Object array2[]){
return equals(array1, 0, array2, 0, array2.length);
}
/** Returns true if array1 ends with array2 */
public static boolean endsWith(Object array1[], Object array2[]){
return equals(array1, array1.length-array2.length, array2, 0, array2.length);
}
/*-------------------------------------------------[ Copy ]---------------------------------------------------*/
/**
* Copies all elements from {@code src} array to {@code dest} array.
*
* If {@code dest.length<src.length}, it copies only the number of elements
* that can fit in {@code dest} array.
*
* @param src source array
* @param dest destination array
*
* @return the destination array specified
*/
@SuppressWarnings({"SuspiciousSystemArraycopy"})
public static T[] copy(Object src[], T dest[]){
System.arraycopy(src, 0, dest, 0, Math.min(src.length, dest.length));
return dest;
}
/**
* returns the clone of {@code src} array.
*
* @param src source array
* @param componentType the componentType used for the new array created
*
* @return cloned array
*/
@SuppressWarnings({"unchecked"})
public static T[] clone(Object src[], Class componentType){
return copy(src, (T[])Array.newInstance(componentType, src.length));
}
/**
* Returns new array which contains only those elements from given {@code array}
* which are selected by the {@code filter}
*
* @param array the array to be filtered
* @param filter filter to use
*
* @return filtered array
*/
public static T[] filter(T array[], Filter filter){
List filteredList = new ArrayList(array.length);
for(T element: array){
if(filter.select(element))
filteredList.add(element);
}
@SuppressWarnings("unchecked")
T filteredArray[] = (T[])Array.newInstance(array.getClass().getComponentType(), filteredList.size());
return filteredList.toArray(filteredArray);
}
/*-------------------------------------------------[ Concat ]---------------------------------------------------*/
@SuppressWarnings({"unchecked"})
public static T[] concat(Object[] array1, Object array2[], Class componentType){
Object newArray[] = (Object[])Array.newInstance(componentType, array1.length+array2.length);
System.arraycopy(array1, 0, newArray, 0, array1.length);
System.arraycopy(array2, 0, newArray, array1.length, array2.length);
return (T[])newArray;
}
/**
* Returns new array which has all values from array1 and array2 in order.
* The componentType for the new array is determined by the componentTypes of
* two arrays.
*/
public static Object[] concat(Object array1[], Object array2[]){
Class class1 = array1.getClass().getComponentType();
Class class2 = array2.getClass().getComponentType();
Class commonClass = class1.isAssignableFrom(class2)
? class1
: (class2.isAssignableFrom(class1) ? class2 : Object.class);
return concat(array1, array2, commonClass);
}
/*-------------------------------------------------[ toObjectArray ]---------------------------------------------------*/
public static Boolean[] toObjectArray(boolean arr[]){
if(arr==null)
return null;
Boolean result[] = new Boolean[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Character[] toObjectArray(char arr[]){
if(arr==null)
return null;
Character result[] = new Character[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Byte[] toObjectArray(byte arr[]){
if(arr==null)
return null;
Byte result[] = new Byte[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Short[] toObjectArray(short arr[]){
if(arr==null)
return null;
Short result[] = new Short[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Integer[] toObjectArray(int arr[]){
if(arr==null)
return null;
Integer result[] = new Integer[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Long[] toObjectArray(long arr[]){
if(arr==null)
return null;
Long result[] = new Long[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Float[] toObjectArray(float arr[]){
if(arr==null)
return null;
Float result[] = new Float[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
public static Double[] toObjectArray(double arr[]){
if(arr==null)
return null;
Double result[] = new Double[arr.length];
for(int i=arr.length-1; i>=0; i--)
result[i] = arr[i];
return result;
}
/*-------------------------------------------------[ ensureCapacity ]---------------------------------------------------*/
public static byte[] ensureCapacity(byte array[], int capacity){
if(capacity<=0 || capacity-array.length<=0)
return array;
int newCapacity = array.length*2;
if(newCapacity-capacity< 0)
newCapacity = capacity;
if(newCapacity<0){
if(capacity<0) // overflow
throw new OutOfMemoryError();
newCapacity = Integer.MAX_VALUE;
}
return Arrays.copyOf(array, newCapacity);
}
public static char[] ensureCapacity(char array[], int capacity){
if(capacity<=0 || capacity-array.length<=0)
return array;
int newCapacity = array.length*2;
if(newCapacity-capacity< 0)
newCapacity = capacity;
if(newCapacity<0){
if(capacity<0) // overflow
throw new OutOfMemoryError();
newCapacity = Integer.MAX_VALUE;
}
return Arrays.copyOf(array, newCapacity);
}
}