1.1 --- a/openide.util/src/org/openide/util/Enumerations.java Wed Jan 27 17:46:23 2010 -0500
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,601 +0,0 @@
1.4 -/*
1.5 - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 - *
1.7 - * Copyright 1997-2009 Sun Microsystems, Inc. All rights reserved.
1.8 - *
1.9 - * The contents of this file are subject to the terms of either the GNU
1.10 - * General Public License Version 2 only ("GPL") or the Common
1.11 - * Development and Distribution License("CDDL") (collectively, the
1.12 - * "License"). You may not use this file except in compliance with the
1.13 - * License. You can obtain a copy of the License at
1.14 - * http://www.netbeans.org/cddl-gplv2.html
1.15 - * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
1.16 - * specific language governing permissions and limitations under the
1.17 - * License. When distributing the software, include this License Header
1.18 - * Notice in each file and include the License file at
1.19 - * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
1.20 - * particular file as subject to the "Classpath" exception as provided
1.21 - * by Sun in the GPL Version 2 section of the License file that
1.22 - * accompanied this code. If applicable, add the following below the
1.23 - * License Header, with the fields enclosed by brackets [] replaced by
1.24 - * your own identifying information:
1.25 - * "Portions Copyrighted [year] [name of copyright owner]"
1.26 - *
1.27 - * Contributor(s):
1.28 - *
1.29 - * The Original Software is NetBeans. The Initial Developer of the Original
1.30 - * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
1.31 - * Microsystems, Inc. All Rights Reserved.
1.32 - *
1.33 - * If you wish your version of this file to be governed by only the CDDL
1.34 - * or only the GPL Version 2, indicate your decision by adding
1.35 - * "[Contributor] elects to include this software in this distribution
1.36 - * under the [CDDL or GPL Version 2] license." If you do not indicate a
1.37 - * single choice of license, a recipient has the option to distribute
1.38 - * your version of this file under either the CDDL, the GPL Version 2 or
1.39 - * to extend the choice of license to its licensees as provided above.
1.40 - * However, if you add GPL Version 2 code and therefore, elected the GPL
1.41 - * Version 2 license, then the option applies only if the new code is
1.42 - * made subject to such option by the copyright holder.
1.43 - */
1.44 -
1.45 -package org.openide.util;
1.46 -
1.47 -import java.util.ArrayList;
1.48 -import java.util.Arrays;
1.49 -import java.util.Collection;
1.50 -import java.util.Collections;
1.51 -import java.util.Enumeration;
1.52 -import java.util.HashSet;
1.53 -import java.util.Iterator;
1.54 -import java.util.NoSuchElementException;
1.55 -import java.util.Set;
1.56 -
1.57 -/**
1.58 - * Factory methods for various types of {@link Enumeration}.
1.59 - * Allows composition of existing enumerations, filtering their contents, and/or modifying them.
1.60 - * All of this is designed to be done lazily, i.e. elements created on demand.
1.61 - * @since 4.37
1.62 - * @author Jaroslav Tulach
1.63 - * @see NbCollections#checkedEnumerationByFilter
1.64 - * @see NbCollections#iterable(Enumeration)
1.65 - */
1.66 -public final class Enumerations extends Object {
1.67 - /** No instances */
1.68 - private Enumerations() {
1.69 - }
1.70 -
1.71 - /**
1.72 - * An empty enumeration.
1.73 - * Always returns <code>false</code> from
1.74 - * <code>empty().hasMoreElements()</code> and throws <code>NoSuchElementException</code>
1.75 - * from <code>empty().nextElement()</code>.
1.76 - * @return the enumeration
1.77 - */
1.78 - public static final <T> Enumeration<T> empty() {
1.79 - Collection<T> emptyL = Collections.emptyList();
1.80 - return Collections.enumeration(emptyL);
1.81 - }
1.82 -
1.83 - /**
1.84 - * Creates an enumeration with one element.
1.85 - * @param obj the element to be present in the enumeration.
1.86 - * @return enumeration
1.87 - */
1.88 - public static <T> Enumeration<T> singleton(T obj) {
1.89 - return Collections.enumeration(Collections.singleton(obj));
1.90 - }
1.91 -
1.92 - /**
1.93 - * Concatenates the content of two enumerations into one.
1.94 - * Until the
1.95 - * end of <code>en1</code> is reached its elements are being served.
1.96 - * As soon as the <code>en1</code> has no more elements, the content
1.97 - * of <code>en2</code> is being returned.
1.98 - *
1.99 - * @param en1 first enumeration
1.100 - * @param en2 second enumeration
1.101 - * @return enumeration
1.102 - */
1.103 - public static <T> Enumeration<T> concat(Enumeration<? extends T> en1, Enumeration<? extends T> en2) {
1.104 - ArrayList<Enumeration<? extends T>> two = new ArrayList<Enumeration<? extends T>>();
1.105 - two.add(en1);
1.106 - two.add(en2);
1.107 - return new SeqEn<T>(Collections.enumeration(two));
1.108 - }
1.109 -
1.110 - /**
1.111 - * Concatenates the content of many enumerations.
1.112 - * The input value
1.113 - * is enumeration of Enumeration elements and the result is composed
1.114 - * all their content. Each of the provided enumeration is fully read
1.115 - * and their content returned before the next enumeration is asked for
1.116 - * their elements.
1.117 - *
1.118 - * @param enumOfEnums Enumeration of Enumeration elements
1.119 - * @return enumeration
1.120 - */
1.121 - public static <T> Enumeration<T> concat(Enumeration<? extends Enumeration<? extends T>> enumOfEnums) {
1.122 - return new SeqEn<T>(enumOfEnums);
1.123 - }
1.124 -
1.125 - /**
1.126 - * Filters the input enumeration to new one that should contain
1.127 - * each of the provided elements just once.
1.128 - * The elements are compared
1.129 - * using their default <code>equals</code> and <code>hashCode</code> methods.
1.130 - *
1.131 - * @param en enumeration to filter
1.132 - * @return enumeration without duplicated items
1.133 - */
1.134 - public static <T> Enumeration<T> removeDuplicates(Enumeration<T> en) {
1.135 - class RDupls implements Processor<T,T> {
1.136 - private Set<T> set = new HashSet<T>();
1.137 -
1.138 - public T process(T o, Collection<T> nothing) {
1.139 - return set.add(o) ? o : null;
1.140 - }
1.141 - }
1.142 -
1.143 - return filter(en, new RDupls());
1.144 - }
1.145 -
1.146 - /**
1.147 - * Returns an enumeration that iterates over provided array.
1.148 - * @param arr the array of object
1.149 - * @return enumeration of those objects
1.150 - */
1.151 - public static <T> Enumeration<T> array(T... arr) {
1.152 - return Collections.enumeration(Arrays.asList(arr));
1.153 - }
1.154 -
1.155 - /**
1.156 - * Removes all <code>null</code>s from the input enumeration.
1.157 - * @param en enumeration that can contain nulls
1.158 - * @return new enumeration without null values
1.159 - */
1.160 - public static <T> Enumeration<T> removeNulls(Enumeration<T> en) {
1.161 - return filter(en, new RNulls<T>());
1.162 - }
1.163 -
1.164 - /**
1.165 - * For each element of the input enumeration <code>en</code> asks the
1.166 - * {@link Processor} to provide a replacement.
1.167 - * The <code>toAdd</code> argument of the processor is always null.
1.168 - * <p>
1.169 - * Example to convert any objects into strings:
1.170 - * <pre>
1.171 - * Processor convertToString = new Processor() {
1.172 - * public Object process(Object obj, Collection alwaysNull) {
1.173 - * return obj.toString(); // converts to string
1.174 - * }
1.175 - * };
1.176 - * Enumeration strings = Enumerations.convert(elems, convertToString);
1.177 - * </pre>
1.178 - *
1.179 - * @param en enumeration of any objects
1.180 - * @param processor a callback processor for the elements (its toAdd arguments is always null)
1.181 - * @return new enumeration where all elements has been processed
1.182 - */
1.183 - public static <T,R> Enumeration<R> convert(Enumeration<? extends T> en, Processor<T,R> processor) {
1.184 - return new AltEn<T,R>(en, processor);
1.185 - }
1.186 -
1.187 - /**
1.188 - * Filters some elements out from the input enumeration.
1.189 - * Just make the
1.190 - * {@link Processor} return <code>null</code>. Please notice the <code>toAdd</code>
1.191 - * argument of the processor is always <code>null</code>.
1.192 - * <p>
1.193 - * Example to remove all objects that are not strings:
1.194 - * <pre>
1.195 - * Processor onlyString = new Processor() {
1.196 - * public Object process(Object obj, Collection alwaysNull) {
1.197 - * if (obj instanceof String) {
1.198 - * return obj;
1.199 - * } else {
1.200 - * return null;
1.201 - * }
1.202 - * }
1.203 - * };
1.204 - * Enumeration strings = Enumerations.filter(elems, onlyString);
1.205 - * </pre>
1.206 - *
1.207 - * @param en enumeration of any objects
1.208 - * @param filter a callback processor for the elements (its toAdd arguments is always null)
1.209 - * @return new enumeration which does not include non-processed (returned null from processor) elements
1.210 - * @see NbCollections#checkedEnumerationByFilter
1.211 - */
1.212 - public static <T,R> Enumeration<R> filter(Enumeration<? extends T> en, Processor<T,R> filter) {
1.213 - Parameters.notNull("en", en);
1.214 - Parameters.notNull("filter", filter);
1.215 - return new FilEn<T,R>(en, filter);
1.216 - }
1.217 -
1.218 - /**
1.219 - * Support for breadth-first enumerating.
1.220 - * Before any element is returned
1.221 - * for the resulting enumeration it is processed in the {@link Processor} and
1.222 - * the processor is allowed to modify it and also add additional elements
1.223 - * at the (current) end of the <q>queue</q> by calling <code>toAdd.add</code>
1.224 - * or <code>toAdd.addAll</code>. No other methods can be called on the
1.225 - * provided <code>toAdd</code> collection.
1.226 - * <p>
1.227 - * Example of doing breadth-first walk through a tree:
1.228 - * <pre>
1.229 - * Processor queueSubnodes = new Processor() {
1.230 - * public Object process(Object obj, Collection toAdd) {
1.231 - * Node n = (Node)obj;
1.232 - * toAdd.addAll (n.getChildrenList());
1.233 - * return n;
1.234 - * }
1.235 - * };
1.236 - * Enumeration strings = Enumerations.queue(elems, queueSubnodes);
1.237 - * </pre>
1.238 - *
1.239 - * @param en initial content of the resulting enumeration
1.240 - * @param filter the processor that is called for each element and can
1.241 - * add and addAll elements to its toAdd Collection argument and
1.242 - * also change the value to be returned
1.243 - * @return enumeration with the initial and queued content (it can contain
1.244 - * <code>null</code> if the filter returned <code>null</code> from its
1.245 - * {@link Processor#process} method.
1.246 - */
1.247 - public static <T,R> Enumeration<R> queue(Enumeration<? extends T> en, Processor<T,R> filter) {
1.248 - QEn<T,R> q = new QEn<T,R>(filter);
1.249 -
1.250 - while (en.hasMoreElements()) {
1.251 - q.put(en.nextElement());
1.252 - }
1.253 -
1.254 - return q;
1.255 - }
1.256 -
1.257 - /**
1.258 - * Processor interface that can filter out objects from the enumeration,
1.259 - * change them or add aditional objects to the end of the current enumeration.
1.260 - */
1.261 - public static interface Processor<T,R> {
1.262 - /** @param original the object that is going to be returned from the enumeration right now
1.263 - * @return a replacement for this object
1.264 - * @param toAdd can be non-null if one can add new objects at the end of the enumeration
1.265 - */
1.266 - public R process(T original, Collection<T> toAdd);
1.267 - }
1.268 -
1.269 - /** Altering enumeration implementation */
1.270 - private static final class AltEn<T,R> extends Object implements Enumeration<R> {
1.271 - /** enumeration to filter */
1.272 - private Enumeration<? extends T> en;
1.273 -
1.274 - /** map to alter */
1.275 - private Processor<T,R> process;
1.276 -
1.277 - /**
1.278 - * @param en enumeration to filter
1.279 - */
1.280 - public AltEn(Enumeration<? extends T> en, Processor<T,R> process) {
1.281 - this.en = en;
1.282 - this.process = process;
1.283 - }
1.284 -
1.285 - /** @return true if there is more elements in the enumeration
1.286 - */
1.287 - public boolean hasMoreElements() {
1.288 - return en.hasMoreElements();
1.289 - }
1.290 -
1.291 - /** @return next object in the enumeration
1.292 - * @exception NoSuchElementException can be thrown if there is no next object
1.293 - * in the enumeration
1.294 - */
1.295 - public R nextElement() {
1.296 - return process.process(en.nextElement(), null);
1.297 - }
1.298 - }
1.299 - // end of AltEn
1.300 -
1.301 - /** Sequence of enumerations */
1.302 - private static final class SeqEn<T> extends Object implements Enumeration<T> {
1.303 - /** enumeration of Enumerations */
1.304 - private Enumeration<? extends Enumeration<? extends T>> en;
1.305 -
1.306 - /** current enumeration */
1.307 - private Enumeration<? extends T> current;
1.308 -
1.309 - /** is {@link #current} up-to-date and has more elements?
1.310 - * The combination <CODE>current == null</CODE> and
1.311 - * <CODE>checked == true means there are no more elements
1.312 - * in this enumeration.
1.313 - */
1.314 - private boolean checked = false;
1.315 -
1.316 - /** Constructs new enumeration from already existing. The elements
1.317 - * of <CODE>en</CODE> should be also enumerations. The resulting
1.318 - * enumeration contains elements of such enumerations.
1.319 - *
1.320 - * @param en enumeration of Enumerations that should be sequenced
1.321 - */
1.322 - public SeqEn(Enumeration<? extends Enumeration <? extends T>> en) {
1.323 - this.en = en;
1.324 - }
1.325 -
1.326 - /** Ensures that current enumeration is set. If there aren't more
1.327 - * elements in the Enumerations, sets the field <CODE>current</CODE> to null.
1.328 - */
1.329 - private void ensureCurrent() {
1.330 - while ((current == null) || !current.hasMoreElements()) {
1.331 - if (en.hasMoreElements()) {
1.332 - current = en.nextElement();
1.333 - } else {
1.334 - // no next valid enumeration
1.335 - current = null;
1.336 -
1.337 - return;
1.338 - }
1.339 - }
1.340 - }
1.341 -
1.342 - /** @return true if we have more elements */
1.343 - public boolean hasMoreElements() {
1.344 - if (!checked) {
1.345 - ensureCurrent();
1.346 - checked = true;
1.347 - }
1.348 -
1.349 - return current != null;
1.350 - }
1.351 -
1.352 - /** @return next element
1.353 - * @exception NoSuchElementException if there is no next element
1.354 - */
1.355 - public T nextElement() {
1.356 - if (!checked) {
1.357 - ensureCurrent();
1.358 - }
1.359 -
1.360 - if (current != null) {
1.361 - checked = false;
1.362 -
1.363 - return current.nextElement();
1.364 - } else {
1.365 - checked = true;
1.366 - throw new java.util.NoSuchElementException();
1.367 - }
1.368 - }
1.369 - }
1.370 - // end of SeqEn
1.371 -
1.372 - /** QueueEnumeration
1.373 - */
1.374 - private static class QEn<T,R> extends Object implements Enumeration<R> {
1.375 - /** next object to be returned */
1.376 - private ListItem<T> next = null;
1.377 -
1.378 - /** last object in the queue */
1.379 - private ListItem<T> last = null;
1.380 -
1.381 - /** processor to use */
1.382 - private Processor<T,R> processor;
1.383 -
1.384 - public QEn(Processor<T,R> p) {
1.385 - this.processor = p;
1.386 - }
1.387 -
1.388 - /** Put adds new object to the end of queue.
1.389 - * @param o the object to add
1.390 - */
1.391 - public void put(T o) {
1.392 - if (last != null) {
1.393 - ListItem<T> li = new ListItem<T>(o);
1.394 - last.next = li;
1.395 - last = li;
1.396 - } else {
1.397 - next = last = new ListItem<T>(o);
1.398 - }
1.399 - }
1.400 -
1.401 - /** Adds array of objects into the queue.
1.402 - * @param arr array of objects to put into the queue
1.403 - */
1.404 - public void put(Collection<? extends T> arr) {
1.405 - for (T e : arr) {
1.406 - put(e);
1.407 - }
1.408 - }
1.409 -
1.410 - /** Is there any next object?
1.411 - * @return true if there is next object, false otherwise
1.412 - */
1.413 - public boolean hasMoreElements() {
1.414 - return next != null;
1.415 - }
1.416 -
1.417 - /** @return next object in enumeration
1.418 - * @exception NoSuchElementException if there is no next object
1.419 - */
1.420 - public R nextElement() {
1.421 - if (next == null) {
1.422 - throw new NoSuchElementException();
1.423 - }
1.424 -
1.425 - T res = next.object;
1.426 -
1.427 - if ((next = next.next) == null) {
1.428 - last = null;
1.429 - }
1.430 -
1.431 - ;
1.432 -
1.433 - ToAdd<T,R> toAdd = new ToAdd<T,R>(this);
1.434 - R out = processor.process(res, toAdd);
1.435 - toAdd.finish();
1.436 -
1.437 - return out;
1.438 - }
1.439 -
1.440 - /** item in linked list of Objects */
1.441 - private static final class ListItem<T> {
1.442 - T object;
1.443 - ListItem<T> next;
1.444 -
1.445 - /** @param o the object for this item */
1.446 - ListItem(T o) {
1.447 - object = o;
1.448 - }
1.449 - }
1.450 -
1.451 - /** Temporary collection that supports only add and addAll operations*/
1.452 - private static final class ToAdd<T,R> extends Object implements Collection<T> {
1.453 - private QEn<T,R> q;
1.454 -
1.455 - public ToAdd(QEn<T,R> q) {
1.456 - this.q = q;
1.457 - }
1.458 -
1.459 - public void finish() {
1.460 - this.q = null;
1.461 - }
1.462 -
1.463 - public boolean add(T o) {
1.464 - q.put(o);
1.465 -
1.466 - return true;
1.467 - }
1.468 -
1.469 - public boolean addAll(Collection<? extends T> c) {
1.470 - q.put(c);
1.471 -
1.472 - return true;
1.473 - }
1.474 -
1.475 - private String msg() {
1.476 - return "Only add and addAll are implemented"; // NOI18N
1.477 - }
1.478 -
1.479 - public void clear() {
1.480 - throw new UnsupportedOperationException(msg());
1.481 - }
1.482 -
1.483 - public boolean contains(Object o) {
1.484 - throw new UnsupportedOperationException(msg());
1.485 - }
1.486 -
1.487 - public boolean containsAll(Collection c) {
1.488 - throw new UnsupportedOperationException(msg());
1.489 - }
1.490 -
1.491 - public boolean isEmpty() {
1.492 - throw new UnsupportedOperationException(msg());
1.493 - }
1.494 -
1.495 - public Iterator<T> iterator() {
1.496 - throw new UnsupportedOperationException(msg());
1.497 - }
1.498 -
1.499 - public boolean remove(Object o) {
1.500 - throw new UnsupportedOperationException(msg());
1.501 - }
1.502 -
1.503 - public boolean removeAll(Collection c) {
1.504 - throw new UnsupportedOperationException(msg());
1.505 - }
1.506 -
1.507 - public boolean retainAll(Collection c) {
1.508 - throw new UnsupportedOperationException(msg());
1.509 - }
1.510 -
1.511 - public int size() {
1.512 - throw new UnsupportedOperationException(msg());
1.513 - }
1.514 -
1.515 - public Object[] toArray() {
1.516 - throw new UnsupportedOperationException(msg());
1.517 - }
1.518 -
1.519 - public<X> X[] toArray(X[] a) {
1.520 - throw new UnsupportedOperationException(msg());
1.521 - }
1.522 - }
1.523 - // end of ToAdd
1.524 - }
1.525 - // end of QEn
1.526 -
1.527 - /** Filtering enumeration */
1.528 - private static final class FilEn<T,R> extends Object implements Enumeration<R> {
1.529 - /** marker object stating there is no nexte element prepared */
1.530 - private static final Object EMPTY = new Object();
1.531 -
1.532 - /** enumeration to filter */
1.533 - private Enumeration<? extends T> en;
1.534 -
1.535 - /** element to be returned next time or {@link #EMPTY} if there is
1.536 - * no such element prepared */
1.537 - private R next = empty();
1.538 -
1.539 - /** the set to use as filter */
1.540 - private Processor<T,R> filter;
1.541 -
1.542 - /**
1.543 - * @param en enumeration to filter
1.544 - */
1.545 - public FilEn(Enumeration<? extends T> en, Processor<T,R> filter) {
1.546 - this.en = en;
1.547 - this.filter = filter;
1.548 - }
1.549 -
1.550 - /** @return true if there is more elements in the enumeration
1.551 - */
1.552 - public boolean hasMoreElements() {
1.553 - if (next != empty()) {
1.554 - // there is a object already prepared
1.555 - return true;
1.556 - }
1.557 -
1.558 - while (en.hasMoreElements()) {
1.559 - // read next
1.560 - next = filter.process(en.nextElement(), null);
1.561 -
1.562 - if (next != null) {
1.563 - // if the object is accepted
1.564 - return true;
1.565 - }
1.566 -
1.567 - ;
1.568 - }
1.569 -
1.570 - next = empty();
1.571 -
1.572 - return false;
1.573 - }
1.574 -
1.575 - /** @return next object in the enumeration
1.576 - * @exception NoSuchElementException can be thrown if there is no next object
1.577 - * in the enumeration
1.578 - */
1.579 - public R nextElement() {
1.580 - if ((next == EMPTY) && !hasMoreElements()) {
1.581 - throw new NoSuchElementException();
1.582 - }
1.583 -
1.584 - R res = next;
1.585 - next = empty();
1.586 -
1.587 - return res;
1.588 - }
1.589 -
1.590 - @SuppressWarnings("unchecked")
1.591 - private R empty() {
1.592 - return (R)EMPTY;
1.593 - }
1.594 - }
1.595 - // end of FilEn
1.596 -
1.597 - /** Returns true from contains if object is not null */
1.598 - private static class RNulls<T> implements Processor<T,T> {
1.599 - public T process(T original, Collection<T> toAdd) {
1.600 - return original;
1.601 - }
1.602 - }
1.603 - // end of RNulls
1.604 -}