de.mhus.lib.core.MCollection Maven / Gradle / Ivy
package de.mhus.lib.core;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeSet;
/**
* MCollection class.
*
* @author mikehummel
* @version $Id: $Id
*/
public class MCollection {
/**
* Returns true of array is not null and the value of item is included in
* the array. It compares with the equals() method of the array item. Also
* a item value of null will be compared.
*
* @param array an array of {@link java.lang.Object} objects.
* @param item a {@link java.lang.Object} object.
* @return a boolean.
*/
public static boolean contains(Object[] array, Object item) {
if (array == null) return false;
for (Object o : array) {
if (item == null && o == null || o != null && o.equals(item)) return true;
}
return false;
}
/**
* Fills a list at the end with the values of an array, ignoring null values.
*
* @param array an array of T objects.
* @param list a {@link java.util.Collection} object.
* @param a T object.
*/
public static void copyArray(T[] array, Collection list) {
if (array == null || list == null) return;
for (T item : array)
if (item != null) list.add(item);
}
//from http://stackoverflow.com/questions/203984/how-do-i-remove-repeated-elements-from-arraylist
/**
* remove duplicated entries
*
* @param list a {@link java.util.List} object.
* @param a T object.
*/
public static void removeDuplicates(List list) {
final Set encountered = new HashSet();
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
final T t = iter.next();
final boolean first = encountered.add(t);
if (!first) {
iter.remove();
}
}
}
/**
* remove duplicated entries, Attention exponential runtime behavior !!!
* Running from beginning to the end, the first element will be left, following removed.
*
* @param list a {@link java.util.List} object.
* @param comparator a {@link java.util.Comparator} object.
* @param a T object.
*/
public static void removeDuplicates(List list, Comparator comparator) {
final Set encountered = new HashSet<>();
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
final T t = iter.next();
boolean removed = false;
for (Iterator iter2 = encountered.iterator(); iter2.hasNext(); ) {
final T e = iter2.next();
if (comparator.compare(t, e) == 0) {
iter.remove();
removed = true;
break;
}
}
if (!removed) {
encountered.add(t);
}
}
}
/**
* append.
*
* @param array an array of T objects.
* @param newElements a T object.
* @param a T object.
* @return an array of T objects.
*/
@SafeVarargs
public static T[] append(T[] array,T ... newElements) {
if (newElements == null || newElements.length == 0) return array;
if (array == null) return newElements;
@SuppressWarnings("unchecked")
T[] newArray = (T[]) Array.newInstance(array.getClass().getComponentType(), array.length + newElements.length);
System.arraycopy(array, 0, newArray, 0, array.length);
System.arraycopy(newElements, 0, newArray, array.length, newElements.length);
return newArray;
}
/**
* order.
*
* @param array an array of int.
* @param unique a boolean.
* @return an array of int.
*/
public static int[] order(int[] array, boolean unique) {
if (unique) {
HashSet set = new HashSet<>();
for (int i : array)
set.add(i);
int[] out = new int[set.size()];
Iterator iter = set.iterator();
for (int i = 0; i < out.length; i++)
out[i] = iter.next();
return out;
}
LinkedList list = new LinkedList<>();
for (int i : array)
list.add(i);
Collections.sort(list);
int[] out = new int[list.size()];
Iterator iter = list.iterator();
for (int i = 0; i < out.length; i++)
out[i] = iter.next();
return out;
}
/**
* order.
*
* @param array an array of long.
* @param unique a boolean.
* @return an array of long.
*/
public static long[] order(long[] array, boolean unique) {
if (unique) {
HashSet set = new HashSet<>();
for (long i : array)
set.add(i);
long[] out = new long[set.size()];
Iterator iter = set.iterator();
for (int i = 0; i < out.length; i++)
out[i] = iter.next();
return out;
}
LinkedList list = new LinkedList<>();
for (long i : array)
list.add(i);
Collections.sort(list);
long[] out = new long[list.size()];
Iterator iter = list.iterator();
for (int i = 0; i < out.length; i++)
out[i] = iter.next();
return out;
}
/**
* fillIntArray.
*
* @param from a int.
* @param to a int.
* @return an array of int.
*/
public static int[] fillIntArray(int from, int to) {
int[] out = new int[to-from];
for (int l = 0; l < out.length; l++)
out[l] = l+from;
return out;
}
/**
* toStringMap.
*
* @param in a {@link java.util.Map} object.
* @param ignoreNull a boolean.
* @return a {@link java.util.Map} object.
* @since 3.2.9
*/
public static Map toStringMap(Map in, boolean ignoreNull) {
HashMap out = new HashMap();
for (Entry e : in.entrySet()) {
if (e.getValue() == null) {
if (!ignoreNull)
out.put(e.getKey().toString(), "");
} else {
out.put(e.getKey().toString(), e.getValue().toString());
}
}
return out;
}
/**
* toStringMap.
*
* @param in a {@link de.mhus.lib.core.IProperties} object.
* @param ignoreNull a boolean.
* @return a {@link java.util.Map} object.
* @since 3.2.9
*/
public static Map toStringMap(IProperties in, boolean ignoreNull) {
HashMap out = new HashMap();
for (Map.Entry e : in) {
if (e.getValue() == null) {
if (!ignoreNull)
out.put(e.getKey(), "");
} else {
out.put(e.getKey(), e.getValue().toString());
}
}
return out;
}
/**
* toList.
*
* @param array an array of T objects.
* @param a T object.
* @return a {@link java.util.List} object.
*/
public static List toList(T[] array) {
LinkedList out = new LinkedList<>();
for (T item : array)
out.add(item);
return out;
}
}
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