View Javadoc
1   /**
2    * This file Copyright (c) 2015-2018 Magnolia International
3    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
4    *
5    *
6    * This file is dual-licensed under both the Magnolia
7    * Network Agreement and the GNU General Public License.
8    * You may elect to use one or the other of these licenses.
9    *
10   * This file is distributed in the hope that it will be
11   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12   * implied warranty of MERCHANTABILITY or FITNESS FOR A
13   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14   * Redistribution, except as permitted by whichever of the GPL
15   * or MNA you select, is prohibited.
16   *
17   * 1. For the GPL license (GPL), you can redistribute and/or
18   * modify this file under the terms of the GNU General
19   * Public License, Version 3, as published by the Free Software
20   * Foundation.  You should have received a copy of the GNU
21   * General Public License, Version 3 along with this program;
22   * if not, write to the Free Software Foundation, Inc., 51
23   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24   *
25   * 2. For the Magnolia Network Agreement (MNA), this file
26   * and the accompanying materials are made available under the
27   * terms of the MNA which accompanies this distribution, and
28   * is available at http://www.magnolia-cms.com/mna.html
29   *
30   * Any modifications to this file must keep this entire header
31   * intact.
32   *
33   */
34  package info.magnolia.resourceloader.util;
35  
36  import info.magnolia.resourceloader.Resource;
37  import info.magnolia.resourceloader.ResourceOrigin;
38  import info.magnolia.resourceloader.layered.LayeredResourceOrigin;
39  
40  import java.util.ArrayList;
41  import java.util.Collection;
42  import java.util.Comparator;
43  import java.util.Objects;
44  import java.util.function.Function;
45  import java.util.function.Predicate;
46  import java.util.regex.Pattern;
47  
48  import com.google.common.base.Predicates;
49  
50  /**
51   * Functional-ish {@link Function}, {@link Predicate} and {@link Comparator} implementations that are useful when working with {@link ResourceOrigin} and {@link Resource}, and some more useful ones that had no better place for now.
52   * They are used to implement {@link LayeredResourceOrigin}, but could be reused for filtering and other purposes.
53   *
54   * // TODO consistent naming -- handle or path
55   * Most of this would be completely redundant with Java 8, since all these do is delegate to a given method of the input object: simple method references as lambdas would suffice.
56   */
57  public class Functions {
58  
59      /**
60       * @deprecated since 6.1 use {@link ResourceOrigin#hasPath} and lambdas
61       */
62      @Deprecated
63      public static Predicate<ResourceOrigin> hasPath(final String path) {
64          return origin -> origin.hasPath(path);
65      }
66  
67      public static Predicate<Resource> pathEquals(final CharSequence path) {
68          return pathMatches(path2 -> Objects.equals(path2, path));
69      }
70  
71      public static Predicate<Resource> pathStartsWith(final CharSequence pathPrefix) {
72          return pathMatches("^" + pathPrefix);
73      }
74  
75      /**
76       * @see #pathMatches(Pattern)
77       * @see #pathMatches(Predicate)
78       */
79      public static Predicate<Resource> pathMatches(final String pattern) {
80          return pathMatches(Predicates.containsPattern(pattern));
81      }
82  
83      /**
84       * Matches if the input {@link Resource}'s handle matches the given pattern.
85       * Matches incomplete strings by default, e.g <code>/bar</code> pattern will match the <code>/foo/bar/qux</code> resource,
86       * while <code>^/bar</code> won't.
87       * @see #pathMatches(String)
88       * @see #pathMatches(Predicate)
89       */
90      public static Predicate<Resource> pathMatches(final Pattern pattern) {
91          return pathMatches(Predicates.contains(pattern));
92      }
93  
94      /**
95       * @see #pathMatches(String)
96       * @see #pathMatches(Pattern)
97       */
98      public static Predicate<Resource> pathMatches(final Predicate<CharSequence> predicate) {
99          return input -> predicate.test(input.getPath());
100     }
101 
102     /**
103      * @deprecated since 6.1 use {@link Resource#isDirectory()} method reference
104      */
105     @Deprecated
106     public static Predicate<Resource> isDirectory() {
107         return Resource::isDirectory;
108     }
109 
110     /**
111      * @deprecated since 6.1 use {@link Resource#isFile()} method reference
112      */
113     @Deprecated
114     public static Predicate<Resource> isFile() {
115         return Resource::isFile;
116     }
117 
118     /**
119      * Convenient Predicate which simply returns true, avoids verbose type parameter declaration and provides a (debatably) better name.
120      * @deprecated since 6.1 use concise lambdas with better parameter name
121      */
122     @Deprecated
123     public static Predicate<Resource> always() {
124         return resource -> true;
125     }
126 
127     /**
128      * Convenient Predicate which simply returns false, avoids verbose type parameter declaration, and provides a (debatably) better name.
129      * @deprecated since 6.1 use concise lambdas with better parameter name
130      */
131     @Deprecated
132     public static Predicate<Resource> never() {
133         return resource -> false;
134     }
135 
136     /**
137      * Convenient Predicate which simply returns true, avoids verbose type parameter declaration and provides a (debatably) better name.
138      *
139      * @deprecated since 6.1 use {@link ResourceOrigin#getByPath(String)} and lambdas
140      */
141     @Deprecated
142     public static Function<ResourceOrigin, Resource> getByPath(final String path) {
143         return origin -> origin.getByPath(path);
144     }
145 
146     /**
147      * @deprecated since 6.1 use {@link ResourceOrigin#getRoot()} method reference
148      */
149     @Deprecated
150     public static Function<ResourceOrigin, Resource> getRoot() {
151         return ResourceOrigin::getRoot;
152     }
153 
154     /**
155      * @deprecated since 6.1 use {@link Resource#getPath()} method reference
156      */
157     @Deprecated
158     public static Function<Resource, String> getPath() {
159         return Resource::getPath;
160     }
161 
162     /**
163      * @deprecated since 6.1 use {@link Resource#getParent()} method reference
164      */
165     @Deprecated
166     public static Function<Resource, Resource> getParent() {
167         return Resource::getParent;
168     }
169 
170     /**
171      * This Function simply collects all input into the given target collection.
172      * It adds elements to the given target collection, but it can also be retrieved with {@link CollectorFunction#getTarget()}
173      */
174     public static <T> CollectorFunction<T> collector(final Collection<T> target) {
175         return new CollectorFunction<>(target);
176     }
177 
178     /**
179      * This Function simply collects all input into a new collection.
180      * The collection can be retrieved with {@link CollectorFunction#getTarget()}
181      */
182     public static <T> CollectorFunction<T> collector() {
183         return new CollectorFunction<>(new ArrayList<>());
184     }
185 
186     /**
187      * @deprecated since 6.1 use static {@link Comparator#comparing(Function)} with {@link Resource#getPath()} method reference
188      */
189     @Deprecated
190     public static <R extends Resource> Comparator<R> compareByHandle() {
191         return Comparator.comparing(Resource::getPath);
192     }
193 
194     /**
195      * A simple Function which aggregates arguments from all its invocations.
196      *
197      * @param <T> the argument type for the function
198      */
199     public static class CollectorFunction<T> extends VoidFunction<T> {
200         private final Collection<T> target;
201 
202         private CollectorFunction(Collection<T> target) {
203             this.target = target;
204         }
205 
206         @Override
207         public void doWith(T input) {
208             target.add(input);
209         }
210 
211         public Collection<T> getTarget() {
212             return target;
213         }
214     }
215 }