1 /*
2 * Licensed under the Apache License, Version 2.0 (the "License");
3 * you may not use this file except in compliance with the License.
4 * You may obtain a copy of the License at
5 *
6 * http://www.apache.org/licenses/LICENSE-2.0
7 *
8 * Unless required by applicable law or agreed to in writing, software
9 * distributed under the License is distributed on an "AS IS" BASIS,
10 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 * See the License for the specific language governing permissions and
12 * limitations under the License.
13 */
14 package org.apache.commons.functor.generator;
15
16 import java.util.Collection;
17
18 import org.apache.commons.functor.UnaryFunction;
19 import org.apache.commons.functor.UnaryProcedure;
20
21 /**
22 * The Generator interface defines a number of useful actions applying UnaryFunctors
23 * to each in a series of argument Objects.
24 *
25 * @param <E> the type of elements held in this generator.
26 * @version $Revision: 1370922 $ $Date: 2012-08-08 15:53:37 -0400 (Wed, 08 Aug 2012) $
27 */
28 public interface Generator<E> {
29 /**
30 * Generators must implement this method.
31 * @param proc UnaryProcedure to run
32 */
33 void run(UnaryProcedure<? super E> proc);
34
35 /**
36 * Stop the generator. Will stop the wrapped generator if one was set.
37 */
38 void stop();
39
40 /**
41 * Check if the generator is stopped.
42 * @return true if stopped
43 */
44 boolean isStopped();
45
46 /**
47 * Transforms this generator using the passed in
48 * transformer. An example transformer might turn the contents of the
49 * generator into a {@link Collection} of elements.
50 * @param <Z> the returned value type of the input {@link UnaryFunction}.
51 * @param transformer UnaryFunction to apply to this
52 * @return transformation result
53 */
54 <Z> Z to(UnaryFunction<Generator<? extends E>, ? extends Z> transformer);
55
56 /**
57 * Same as to(new CollectionTransformer(collection)).
58 * @param collection Collection to which my elements should be added
59 * @return <code>collection</code>
60 */
61 <C extends Collection<? super E>> C to(C collection);
62
63 /**
64 * Same as to(new CollectionTransformer()).
65 * @return Collection
66 */
67 Collection<? super E> toCollection();
68 }