Update #0 - First Release

sources/main/java/com/google/common/hash/Funnel.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2011 The Guava Authors
+ *
+ * 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 com.google.common.hash;
+
+import java.io.Serializable;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * An object which can send data from an object of type {@code T} into a
+ * {@code PrimitiveSink}. Implementations for common types can be found in
+ * {@link Funnels}.
+ *
+ * <p>
+ * Note that serialization of {@linkplain BloomFilter bloom filters} requires
+ * the proper serialization of funnels. When possible, it is recommended that
+ * funnels be implemented as a single-element enum to maintain serialization
+ * guarantees. See Effective Java (2nd Edition), Item 3: "Enforce the singleton
+ * property with a private constructor or an enum type". For example:
+ * 
+ * <pre>
+ *    {@code
+ *   public enum PersonFunnel implements Funnel<Person> {
+ *     INSTANCE;
+ *     public void funnel(Person person, PrimitiveSink into) {
+ *       into.putUnencodedChars(person.getFirstName())
+ *           .putUnencodedChars(person.getLastName())
+ *           .putInt(person.getAge());
+ *     }
+ *   }}
+ * </pre>
+ *
+ * @author Dimitris Andreou
+ * @since 11.0
+ */
+@Beta
+public interface Funnel<T> extends Serializable {
+
+	/**
+	 * Sends a stream of data from the {@code from} object into the sink
+	 * {@code into}. There is no requirement that this data be complete enough to
+	 * fully reconstitute the object later.
+	 *
+	 * @since 12.0 (in Guava 11.0, {@code PrimitiveSink} was named {@code Sink})
+	 */
+	void funnel(T from, PrimitiveSink into);
+}