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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.

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/*
 * Copyright (C) 2004-2014 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;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.databene.commons.iterator.ArrayIterator;

/**
 * Provides array-related operations.

 * 

 * Created: 09.06.2006 21:31:49
 * @since 0.1
 * @author Volker Bergmann
 */
public final class ArrayUtil {

    public static  T[] copyOfRange(T[] array, int offset, int length) {
        return copyOfRange(array, offset, length, componentType(array));
    }

	@SuppressWarnings("unchecked")
    public static  Class componentType(T[] array) {
	    Class resultType = (Class) array.getClass();
        Class componentType = (Class) resultType.getComponentType();
	    return componentType;
    }

    @SuppressWarnings("unchecked")
    public static  T[] copyOfRange(Object[] array, int offset, int length, Class componentType) {
        T[] result = (T[]) Array.newInstance(componentType, length);
        System.arraycopy(array, offset, result, 0, length);
        return result;
    }

    public static  T[] removeElement(T item, T[] array) {
    	int index = indexOf(item, array);
        return remove(index, array);
    }

    @SuppressWarnings("unchecked")
    public static  T[] remove(int indexToRemove, T[] array) {
        Class componentType = componentType(array);
        T[] result = (T[]) Array.newInstance(componentType, array.length - 1);
        if (indexToRemove > 0)
            System.arraycopy(array, 0, result, 0, indexToRemove);
        System.arraycopy(array, indexToRemove + 1, result, indexToRemove, array.length - indexToRemove - 1);
        return result;
    }

	public static  T[] removeAll(T[] toRemove, T[] target) {
        Class componentType = componentType(target);
		ArrayBuilder builder = new ArrayBuilder(componentType);
		for (T element : target)
			if (!contains(element, toRemove))
				builder.add(element);
		return builder.toArray();
	}

    // containment check -----------------------------------------------------------------------------------------------

    /**
     * Tells if an array contains a specific element
     * @param element the element to search
     * @param array the array to scan
     * @return true if the element was found, else false
     */
    public static boolean contains(Object element, Object array) {
    	int length = Array.getLength(array);
        for (int i = 0; i < length; i++) {
        	Object o = Array.get(array, i);
            if (NullSafeComparator.equals(o, element))
                return true;
        }
        return false;
    }

	public static  boolean containsAll(T[] subArray, T[] superArray) {
		for (T t : subArray)
			if (!contains(t, superArray))
				return false;
		return true;
	}

    public static int indexOf(byte[] subArray, byte[] array) {
        return indexOf(subArray, 0, array);
    }

    public static int indexOf(byte[] subArray, int fromIndex, byte[] array) {
        for (int i = fromIndex; i <= array.length - subArray.length; i++) {
        	boolean match = true;
        	for (int j = 0; j < subArray.length; j++) {
	            if (array[i + j] != subArray[j])
	                match = false;
        	}
        	if (match)
        		return i;
        }
        return -1;
    }

    /**
     * Tells if an array ends with a specified sub array
     * @param candidates the array to scan
     * @param searched the sub array that is searched
     * @return true if the array ands with or equals the searched sub array
     */
    public static  boolean endsWithSequence(T[] candidates, T[] searched) {
        if (searched.length > candidates.length)
            return false;
        for (int i = 0; i < searched.length; i++) {
            if (!candidates[candidates.length - searched.length + i].equals(searched[i]))
                return false;
        }
        return true;
    }

    @SuppressWarnings("unchecked")
    public static  T[] commonElements(T[]... sources) {
        Class componentType = null;
        for (int arrayNumber = 0; arrayNumber < sources.length && componentType == null; arrayNumber++) {
            T[] source = sources[arrayNumber];
            for (int index = 0; index < source.length && componentType == null; index++)
                if (source[index] != null)
                    componentType = (Class) source[index].getClass();
        }
        return commonElements(componentType, sources);
    }

    public static  T[] commonElements(Class componentType, T[]... sources) {
        ArrayBuilder builder = new ArrayBuilder(componentType);
        T[] firstArray = sources[0];
        for (T element : firstArray) {
            boolean common = true;
            for (int i = 1; i < sources.length; i++)
                if (!ArrayUtil.contains(element, sources[i])) {
                    common = false;
                    break;
                }
            if (common)
                builder.add(element);
        }
        return builder.toArray();
    }


    // identity checks -------------------------------------------------------------------------------------------------

    /**
     * Tells if two arrays have the same content, independent of the ordering
     * @param a1 the first array to compare
     * @param a2 the first array to compare
     * @return true if the array have the same content, independent of the ordering
     */
    public static  boolean equalsIgnoreOrder(T[] a1, T[] a2) {
        if (a1 == a2)
            return true;
        if (a1 == null)
            return false;
        if (a1.length != a2.length)
            return false;
        List l1 = new ArrayList(a1.length);
        for (T item : a1)
            l1.add(item);
        for (int i = a1.length - 1; i >= 0; i--)
            if (contains(a1[i], a2))
                l1.remove(i);
            else
                return false;
        return l1.size() == 0;
    }

    public static boolean equals(Object a1, Object a2) {
        if (a1 == a2)
            return true;
        if (a1 == null || !(a1.getClass().isArray()) || !(a2.getClass().isArray()))
            return false;
        int length = Array.getLength(a1);
		if (length != Array.getLength(a2))
            return false;
        List l1 = new ArrayList(length);
        for (int i = 0; i < length ; i++)
            l1.add(Array.get(a1, i));
        for (int i = length - 1; i >= 0; i--) {
            if (contains(Array.get(a1, i), a2))
                l1.remove(i);
            else
                return false;
        }
        return l1.size() == 0;
    }

    /**
     * Tells the first index under which an item is found in an array.
     * @param searchedItem
     * @param array
     * @return the index of the searched item
     */
    public static  int indexOf(T searchedItem, T[] array) {
        for (int i = 0; i < array.length; i++) {
            T candidate = array[i];
            if (NullSafeComparator.equals(candidate, searchedItem))
                return i;
        }
        return -1;
    }

    @SuppressWarnings("unchecked")
    public static  T[] toArray(T... values) {
    	Class componentType = (Class) (values.length > 0 ? values[0].getClass() : Object.class);
    	return buildObjectArrayOfType(componentType, values);
    }

    public static int[] toIntArray(int... values) {
        int[] array = new int[values.length];
        System.arraycopy(values, 0, array, 0, values.length);
        return array;
    }

    public static char[] toCharArray(char... values) {
        char[] array = new char[values.length];
        System.arraycopy(values, 0, array, 0, values.length);
        return array;
    }

    public static Object buildArrayOfType(Class componentType, Object ... values) {
        Object array = Array.newInstance(componentType, values.length);
        for (int i = 0; i < values.length; i++)
        	Array.set(array, i, values[i]); // explicit assignment since System.arraycopy() does not perform autoboxing
        return array;
    }
    
    @SuppressWarnings("unchecked")
    public static  T[] buildObjectArrayOfType(Class componentType, T ... values) {
        T[] array = (T[]) Array.newInstance(componentType, values.length);
        System.arraycopy(values, 0, array, 0, values.length);
        return array;
    }
    
    public static  Iterator iterator(T[] array) {
    	return new ArrayIterator(array);
    }

    public static  T[] revert(T[] array) {
        for (int i = (array.length >> 1) - 1 ; i >= 0; i--) {
            T tmp = array[i];
            array[i] = array[array.length - 1 - i];
            array[array.length - 1 - i] = tmp;
        }
        return array;
    }

    public static char[] revert(char[] array) {
        for (int i = (array.length >> 1) - 1; i >= 0; i--) {
            char tmp = array[i];
            array[i] = array[array.length - 1 - i];
            array[array.length - 1 - i] = tmp;
        }
        return array;
    }
    
    @SuppressWarnings("rawtypes")
	public static Class arrayType(Class componentType) { // this cannot be made generic since it needs to support simple types too
    	if (componentType == byte.class)
    		return byte[].class;
    	else if (componentType == char.class)
    		return char[].class;
    	else if (componentType == int.class)
    		return int[].class;
    	else if (componentType == long.class)
    		return long[].class;
    	else if (componentType == short.class)
    		return short[].class;
    	else if (componentType == double.class)
    		return double[].class;
    	else if (componentType == float.class)
    		return float[].class;
    	else if (componentType == boolean.class)
    		return boolean[].class;
        Object[] array = (Object[]) Array.newInstance(componentType, 0);
        return array.getClass();
    }

    @SuppressWarnings("unchecked")
    public static  T[] newInstance(Class componentType, int length) {
        return (T[]) Array.newInstance(componentType, length);
    }

    public static  T[] append(T[] newValues, T[] array) {
        if (array == null) {
            return newValues.clone();
        } else {
            T[] newArray = newInstance(componentType(array), array.length + newValues.length);
            System.arraycopy(array, 0, newArray, 0, array.length);
            for (int i = 0; i < newValues.length; i++)
            	newArray[array.length + i] = newValues[i];
            return newArray;
        }
    }

    @SuppressWarnings("unchecked")
    public static  T[] append(T value, T[] array) {
        if (array == null) {
            return toArray(value);
        } else {
            T[] newArray = newInstance(componentType(array), array.length + 1);
            System.arraycopy(array, 0, newArray, 0, array.length);
            newArray[array.length] = value;
            return newArray;
        }
    }

    public static byte[] append(byte value, byte[] array) {
        if (array == null) {
            return new byte[] { value };
        } else {
            byte[] newArray = new byte[array.length + 1];
            System.arraycopy(array, 0, newArray, 0, array.length);
            newArray[array.length] = value;
            return newArray;
        }
    }

    public static boolean isEmpty(Object values) {
        return (values == null || Array.getLength(values) == 0);
    }

    public static  T lastElementOf(T[] array) {
    	if (isEmpty(array))
    		return null;
    	return array[array.length - 1];
    }

    public static Integer lastElementOf(int[] array) {
    	if (array == null || array.length == 0)
    		return -1;
    	return array[array.length - 1];
    }

	public static boolean allNull(Object[] values) {
		if (values == null)
			return true;
		for (Object value : values)
			if (value != null)
				return false;
	    return true;
    }

}
    

    

    

            

    

            



    
    






    
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