Centralize token generation and formats

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=135313726

java/google/registry/util/TokenUtils.java

@@ -0,0 +1,73 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// 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 google.registry.util;
+
+import com.google.common.base.Function;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+
+/**
+ * A utility class for generating various auth tokens using a common prefixed-based format.
+ * These tokens are generally of the form [TYPE]_[randomstring].
+ */
+public final class TokenUtils {
+
+  /** An enum containing definitions (prefix and length) for token types. */
+  public enum TokenType {
+    ANCHOR_TENANT("ANCHOR", 16),
+    LRP("LRP", 16);
+
+    private final String prefix;
+    private final int length;
+
+    private TokenType(String prefix, int length) {
+      this.prefix = prefix;
+      this.length = length;
+    }
+
+    /** Returns the prefix for a given type. */
+    public String getPrefix() {
+      return prefix;
+    }
+
+    /** Returns the set token length for a given type (not including the prefix). */
+    public int getLength() {
+      return length;
+    }
+  }
+
+  /** Generates a single token of a given {@link TokenType}. */
+  public static String createToken(TokenType type, StringGenerator generator) {
+    return Iterables.getOnlyElement(createTokens(type, generator, 1));
+  }
+
+  /** Generates a {@link Collection} of tokens of a given {@link TokenType}. */
+  public static ImmutableSet<String> createTokens(
+      final TokenType type,
+      StringGenerator generator,
+      int count) {
+    return FluentIterable.from(generator.createStrings(type.getLength(), count))
+        .transform(new Function<String, String>() {
+          @Override
+          public String apply(String token) {
+            return String.format("%s_%s", type.getPrefix(), token);
+          }})
+        .toSet();
+  }
+
+  private TokenUtils() {}
+}
+