Add 'Or' key selection strategy

src/main/java/de/vanitasvitae/crypto/pgpainless/key/selection/key/impl/Or.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2018 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.vanitasvitae.crypto.pgpainless.key.selection.key.impl;
+
+import de.vanitasvitae.crypto.pgpainless.key.selection.key.PublicKeySelectionStrategy;
+import de.vanitasvitae.crypto.pgpainless.key.selection.key.SecretKeySelectionStrategy;
+import org.bouncycastle.openpgp.PGPPublicKey;
+import org.bouncycastle.openpgp.PGPSecretKey;
+
+public class Or {
+
+    public static class PubKeySelectionStrategy<O> extends PublicKeySelectionStrategy<O> {
+
+        private final PublicKeySelectionStrategy<O> left;
+        private final PublicKeySelectionStrategy<O> right;
+
+        public PubKeySelectionStrategy(PublicKeySelectionStrategy<O> left,
+                                       PublicKeySelectionStrategy<O> right) {
+            this.left = left;
+            this.right = right;
+        }
+
+        @Override
+        public boolean accept(O identifier, PGPPublicKey key) {
+            return left.accept(identifier, key) || right.accept(identifier, key);
+        }
+    }
+
+    public static class SecKeySelectionStrategy<O> extends SecretKeySelectionStrategy<O> {
+
+        private final SecretKeySelectionStrategy<O> left;
+        private final SecretKeySelectionStrategy<O> right;
+
+        public SecKeySelectionStrategy(SecretKeySelectionStrategy<O> left,
+                                       SecretKeySelectionStrategy<O> right) {
+            this.left = left;
+            this.right = right;
+        }
+
+        @Override
+        public boolean accept(O identifier, PGPSecretKey key) {
+            return left.accept(identifier, key) || right.accept(identifier, key);
+        }
+    }
+
+}