org.jopendocument.util.CollectionUtils Maven / Gradle / Ivy
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*
* Copyright 2008 jOpenDocument, by ILM Informatique. All rights reserved.
*
* The contents of this file are subject to the terms of the GNU
* General Public License Version 3 only ("GPL").
* You may not use this file except in compliance with the License.
* You can obtain a copy of the License at http://www.gnu.org/licenses/gpl-3.0.html
* See the License for the specific language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each file.
*
*/
package org.jopendocument.util;
import org.jopendocument.util.cc.ITransformer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.RandomAccess;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.regex.Pattern;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.TransformerUtils;
/**
* Une classe regroupant des méthodes utilitaires pour les collections.
*
* @author ILM Informatique 30 sept. 2004
*/
public class CollectionUtils extends org.apache.commons.collections.CollectionUtils {
// TODO rm the non generic one
static public final String join(final Collection c, final String sep, final ITransformer tf) {
return join(c, sep, (Transformer) tf);
}
/**
* Concatene une collection. Cette méthode va appliquer un transformation sur chaque élément
* avant d'appeler toString(). join([-1, 3, 0], " ,", doubleTransformer) == "-2, 6, 0"
*
* @param c la collection a concaténer.
* @param sep le séparateur entre chaque élément.
* @param tf la transformation à appliquer à chaque élément.
* @return la chaine composée de chacun des éléments séparés par sep.
* @deprecated use {@link #join(Collection, String, ITransformer)}
*/
static public final String join(final Collection c, final String sep, final Transformer tf) {
if (c.size() == 0)
return "";
final StringBuffer res = new StringBuffer(c.size() * 4);
if (c instanceof RandomAccess && c instanceof List) {
final List list = (List) c;
final int stop = c.size() - 1;
for (int i = 0; i < stop; i++) {
res.append(tf.transform(list.get(i)));
res.append(sep);
}
res.append(tf.transform(list.get(stop)));
} else {
final Iterator iter = c.iterator();
while (iter.hasNext()) {
final Object elem = iter.next();
res.append(tf.transform(elem));
if (iter.hasNext())
res.append(sep);
}
}
return res.toString();
}
/**
* Concatene une collection en appelant simplement toString() sur chaque élément.
*
* @param type of collection
* @param c la collection a concaténer.
* @param sep le séparateur entre chaque élément.
* @return la chaine composée de chacun des éléments séparés par sep.
* @see #join(Collection, String, ITransformer)
*/
static public String join(Collection c, String sep) {
return join(c, sep, ITransformer. nopTransformer());
}
// *** split
private static final Pattern COMMA = Pattern.compile("\\p{Space}*,\\p{Space}*");
static public List split(String s) {
return split(s, COMMA);
}
static public List split(String s, String sep) {
return split(s, Pattern.compile(sep));
}
/**
* Split a string into a list based on a pattern.
*
* @param s the string to split.
* @param pattern the pattern where to cut the string.
* @return the splitted string, empty list if s is "".
*/
static public List split(String s, Pattern pattern) {
return s.length() == 0 ? Collections. emptyList() : Arrays.asList(pattern.split(s));
}
/**
* Return an index between 0 and l.size() inclusive. If
* i is negative, it is added to l.size() (but bounded to 0), ie
* for a list of 3 items, -1 is the index of the last item ; -3 and -4 are both the first. If
* i is greater than l.size() then l.size() is
* returned.
*
*
* a b c a b c
* -3 -2 -1 0 1 2
*
*
* @param l the list, eg a list of 4 items.
* @param i the virtual index, eg -1.
* @return the real index, eg 3.
*/
static public int getValidIndex(final List l, final int i) {
if (i > l.size()) {
return l.size();
} else if (i >= 0) {
return i;
} else if (l.size() + i <= 0)
return 0;
else
return l.size() + i;
}
/**
* Deletes a slice of a list. Pass indexes to {@link #getValidIndex(List, int)}.
*
* @param l the list to delete from.
* @param from the first index to be removed (inclusive).
* @param to the last index to be removed (exclusive).
*/
static public void delete(List l, int from, int to) {
l.subList(getValidIndex(l, from), getValidIndex(l, to)).clear();
}
/**
* Deletes the tail of a list. The resulting list will have a size of from.
*
* @param l the list to delete from.
* @param from the first index to be removed (inclusive).
*/
static public void delete(List l, int from) {
delete(l, from, l.size());
}
/**
* Permet d'organiser une collection en une hiérarchie à l'aide de Map. Avec
* Col = [
* Obs1(bat=BAT A, local=A1, num=1),
* Obs2(bat=BAT B, local=B1, num=2),
* Obs3(bat=BAT B, local=B2, num=3),
* Obs4(bat=BAT B, local=B2, num=4)
* ]
*
* ainsi que deux extracteurs pour trouver le batiment et le local, et enfin itemOrdering suivant le numero, on a
* { BAT A => {A1 => {Obs1}}, {BAT B => {B1 => {Obs2}, B2 => {Obs3, Obs4}}}}.
*
* @param col la collection à organiser.
* @param propExtractors les extracteurs de propriétes.
* @param propComp les Comparator pour les propriétés renvoyées par les extracteurs, peut être
* null si les propriétés sont des Comparable.
* @param itemOrdering comment ordonner les éléments dans la dernière tranche, peut être
* null si les éléments sont des Comparable.
* @return une hiérarchie de SortedMap et en dernier un SortedSet.
*/
static public final SortedMap organize(Collection col, List propExtractors, List propComp, Comparator itemOrdering) {
if (propExtractors.size() == 0)
throw new IllegalArgumentException("Empty property extractors");
if (propComp == null)
propComp = Collections.nCopies(propExtractors.size(), null);
else if (propExtractors.size() != propComp.size())
throw new IllegalArgumentException("Size mismatch between " + propExtractors + " and " + propComp);
final SortedMap res = new TreeMap(propComp.get(0));
Iterator iter = col.iterator();
while (iter.hasNext()) {
final Object item = iter.next();
Map m = res;
for (int i = 0; i < propExtractors.size() - 1; i++) {
final Transformer extractor = propExtractors.get(i);
final Object property = extractor.transform(item);
Map newM = (Map) m.get(property);
if (newM == null) {
newM = new TreeMap(propComp.get(i + 1));
m.put(property, newM);
}
m = newM;
}
final Object property = propExtractors.get(propExtractors.size() - 1).transform(item);
SortedSet s = (SortedSet) m.get(property);
if (s == null) {
s = new TreeSet(itemOrdering);
m.put(property, s);
}
s.add(item);
}
return res;
}
/**
* Permet d'aplatir une hiérarchie. Exemple :
*
*
* A-
* A1
* A2
* B-
* B1
* B11
* B12
*
*
* devient [A, A1, A2, B, B1, B11, B12].
*
* @param hierarchy la hiérarchie à aplatir.
* @param itemTransf la transformation à faire sur les feuilles.
* @return la liste correspondante.
*/
static public final List flatten(Map hierarchy, Transformer itemTransf) {
final List res = new ArrayList();
final Iterator iter = hierarchy.keySet().iterator();
while (iter.hasNext()) {
final Object obj = iter.next();
res.add(obj);
final Object value = hierarchy.get(obj);
if (value instanceof Map)
res.addAll(flatten((Map) value, itemTransf));
else if (value instanceof Collection) {
final Collection items = (Collection) value;
final Iterator itemIter = items.iterator();
while (itemIter.hasNext()) {
final Object item = itemIter.next();
res.add(itemTransf.transform(item));
}
} else
throw new IllegalArgumentException("Illegal value: " + value);
}
return res;
}
/**
* Permet d'aplatir une hiérarchie.
*
* @param hierarchy la hiérarchie à aplatir.
* @return la liste correspondante.
*/
static public final List flatten(Map hierarchy) {
return flatten(hierarchy, TransformerUtils.nopTransformer());
}
/**
* Convertit une map en 2 listes, une pour les clefs, une pour les valeurs.
*
* @param map la Map à convertir.
* @return un tableau de 2 List, en 0 les clefs, en 1 les valeurs.
* @param type of key
* @param type of value
*/
static public List[] mapToLists(Map map) {
final List keys = new ArrayList(map.size());
final List vals = new ArrayList(map.size());
for (final Map.Entry e : map.entrySet()) {
keys.add(e.getKey());
vals.add(e.getValue());
}
return new List[] { keys, vals };
}
/**
* Compute the index that have changed (added or removed) between 2 lists. One of the lists MUST
* be a sublist of the other, ie the to go from one to the other we just add or remove items but
* we don't do both.
*
* @param oldList the first list.
* @param newList the second list.
* @return a list of Integer.
* @param type of item
* @throws IllegalStateException if one list is not a sublist of the other.
*/
static public List getIndexesChanged(List oldList, List newList) {
final List longer;
final List shorter;
if (newList.size() > oldList.size()) {
longer = new ArrayList(newList);
shorter = new ArrayList(oldList);
} else {
longer = new ArrayList(oldList);
shorter = new ArrayList(newList);
}
final List res = new ArrayList();
int offset = 0;
while (shorter.size() > 0) {
if (longer.size() < shorter.size())
throw new IllegalStateException(shorter + " is not a sublist of " + longer);
// compare nulls
if (CompareUtils.equals(shorter.get(0), longer.get(0))) {
shorter.remove(0);
longer.remove(0);
} else {
longer.remove(0);
res.add(offset);
}
offset++;
}
for (int i = 0; i < longer.size(); i++) {
res.add(i + offset);
}
return res;
}
/**
* Aggregate a list of ints into a list of intervals. Eg aggregate([-1,0,1,2,5]) returns
* [[-1,2], [5,5]].
*
* @param ints a list of Integer strictly increasing.
* @return a list of int[2].
*/
static public List aggregate(Collection ints) {
final List res = new ArrayList();
int[] currentInterval = null;
for (final Number n : ints) {
final int index = n.intValue();
if (currentInterval == null || index != currentInterval[1] + 1) {
currentInterval = new int[2];
currentInterval[0] = index;
currentInterval[1] = currentInterval[0];
res.add(currentInterval);
} else {
currentInterval[1] = index;
}
}
return res;
}
/**
* Test whether col2 is contained in col1.
*
* @param type of collection
* @param col1 the first collection
* @param col2 the second collection
* @return null if col1 contains all of col2, else return the extra items that
* col2 have.
*/
static public Set contains(final Set col1, final Set col2) {
if (col1.containsAll(col2))
return null;
else {
final Set names = new HashSet(col2);
names.removeAll(col1);
return names;
}
}
/**
* Convert an array to a list of a different type.
*
* @param type of array
* @param type of list
* @param array the array to convert, eg new Object[]{"a", "b"}.
* @param clazz the class of the list items, eg String.class.
* @return all items of array into a list, eg ["a", "b"].
* @throws ClassCastException if some item of array is not a T.
*/
static public List castToList(U[] array, Class clazz) throws ClassCastException {
final List res = new ArrayList(array.length);
for (final U item : array) {
res.add(clazz.cast(item));
}
return res;
}
/**
* The number of equals item between a and b, starting from the end.
*
* @param type of items.
* @param a the first list, eg [a, b, c].
* @param b the second list, eg [a, null, z, c].
* @return the number of common items, eg 1.
*/
public static int equalsFromEnd(final List a, final List b) {
return equals(a, b, true, null);
}
public static int equalsFromStart(final List a, final List b) {
return equals(a, b, false, null);
}
/**
* The number of equals item between a and b, starting from the choosen end.
*
* @param type of the first list.
* @param type of the second list.
* @param a the first list, eg [a, b, c].
* @param b the second list, eg [a, null, z, c].
* @param fromEnd whether search from the start or the end, true.
* @param transf how items of a should be transformed before being compared, can
* be null.
* @return the number of common items, eg 1.
*/
public final static int equals(final List a, final List b, boolean fromEnd, ITransformer transf) {
final int sizeA = a.size();
final int sizeB = b.size();
final int lastI = Math.min(sizeA, sizeB);
for (int i = 0; i < lastI; i++) {
final A itemA = a.get(fromEnd ? sizeA - 1 - i : i);
final B itemB = b.get(fromEnd ? sizeB - 1 - i : i);
if (!CompareUtils.equals(transf == null ? itemA : transf.transformChecked(itemA), itemB))
return i;
}
return lastI;
}
@SuppressWarnings("unchecked")
public static Collection inter(final Collection a, final Collection b) {
return org.apache.commons.collections.CollectionUtils.intersection(a, b);
}
/**
* Compute the intersection of a and b. nulls are ignored : x ∩ null = x.
*
* @param type of collection.
* @param a the first set, can be null.
* @param b the second set, can be null.
* @return the intersection.
*/
public static Set inter(final Set a, final Set b) {
if (a == b)
return a;
else if (a == null)
return b;
else if (b == null)
return a;
else if (a.size() > b.size()) {
return inter(b, a);
}
final Set res = new HashSet();
for (final T item : a) {
if (b.contains(item))
res.add(item);
}
return res;
}
public static Set inter(final Set... sets) {
return inter(Arrays.asList(sets));
}
public static Set inter(final List> sets) {
final List> mutable = new ArrayList>(sets.size());
for (final Set s : sets) {
// ignore nulls
if (s != null)
mutable.add(s);
}
if (mutable.isEmpty())
return null;
else if (mutable.size() == 1)
return mutable.get(0);
final int indexMin = indexOfMinSize(mutable);
if (indexMin != 0) {
mutable.add(0, mutable.remove(indexMin));
return inter(mutable);
}
if (mutable.get(0).isEmpty())
return Collections.emptySet();
// replace the first 2 by their intersection
// (inter will swap as appropriate if java doesn't evalute args in source order)
mutable.add(0, inter(mutable.remove(0), mutable.remove(0)));
return inter(mutable);
}
private static final int indexOfMinSize(final List> sets) {
if (sets.isEmpty())
throw new IllegalArgumentException("empty sets");
int res = 0;
for (int i = 1; i < sets.size(); i++) {
if (sets.get(i).size() < sets.get(res).size())
res = i;
}
return res;
}
@SuppressWarnings("unchecked")
public static Collection subtract(final Collection a, final Collection b) {
return org.apache.commons.collections.CollectionUtils.subtract(a, b);
}
@SuppressWarnings("unchecked")
public static Collection substract(final Collection a, final Collection b) {
return org.apache.commons.collections.CollectionUtils.subtract(a, b);
}
/**
* Return the first item of l if it's the only one, otherwise null.
*
* @param type of list.
* @param l the list.
* @return the first item of l or null.
*/
public static T getSole(List l) {
return l.size() == 1 ? l.get(0) : null;
}
public static T getSole(Collection l) {
return l.size() == 1 ? l.iterator().next() : null;
}
public static T getFirst(Collection l) {
return l.size() > 0 ? l.iterator().next() : null;
}
/**
* Return the first item of l if it isn't empty, otherwise null.
*
* @param type of list.
* @param l the list.
* @return the first item of l or null.
*/
public static T getFirst(List l) {
return getNoExn(l, 0);
}
/**
* Return the last item of l if it isn't empty, otherwise null.
*
* @param type of list.
* @param l the list.
* @return the last item of l or null.
*/
public static T getLast(List l) {
return getNoExn(l, l.size() - 1);
}
/**
* Return the item no index of l if it exists, otherwise
* null.
*
* @param type of list.
* @param l the list.
* @param index the wanted index.
* @return the corresponding item of l or null.
*/
public static T getNoExn(List l, int index) {
return index >= 0 && index < l.size() ? l.get(index) : null;
}
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