1 files changed, 148 insertions, 0 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/Protobuf.java b/java/core/src/main/java/com/google/protobuf/Protobuf.java
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+++ b/java/core/src/main/java/com/google/protobuf/Protobuf.java
@@ -0,0 +1,148 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import static com.google.protobuf.Internal.checkNotNull;
+
+import java.io.IOException;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+/**
+ * Main runtime interface for protobuf. Applications should interact with this interface (rather
+ * than directly accessing internal APIs) in order to perform operations on protobuf messages.
+ */
+@ExperimentalApi
+public final class Protobuf {
+  private static final Protobuf INSTANCE = new Protobuf();
+
+  private final SchemaFactory schemaFactory;
+
+  // TODO(nathanmittler): Consider using ClassValue instead.
+  private final ConcurrentMap<Class<?>, Schema<?>> schemaCache =
+      new ConcurrentHashMap<Class<?>, Schema<?>>();
+
+  /** Gets the singleton instance of the Protobuf runtime. */
+  public static Protobuf getInstance() {
+    return INSTANCE;
+  }
+
+  /** Writes the given message to the target {@link Writer}. */
+  public <T> void writeTo(T message, Writer writer) {
+    schemaFor(message).writeTo(message, writer);
+  }
+
+  /** Reads fields from the given {@link Reader} and merges them into the message. */
+  public <T> void mergeFrom(T message, Reader reader) throws IOException {
+    schemaFor(message).mergeFrom(message, reader);
+  }
+
+  /** Gets the schema for the given message type. */
+  public <T> Schema<T> schemaFor(Class<T> messageType) {
+    checkNotNull(messageType, "messageType");
+    @SuppressWarnings("unchecked")
+    Schema<T> schema = (Schema<T>) schemaCache.get(messageType);
+    if (schema == null) {
+      schema = schemaFactory.createSchema(messageType);
+      @SuppressWarnings("unchecked")
+      Schema<T> previous = (Schema<T>) registerSchema(messageType, schema);
+      if (previous != null) {
+        // A new schema was registered by another thread.
+        schema = previous;
+      }
+    }
+    return schema;
+  }
+
+  /** Gets the schema for the given message. */
+  @SuppressWarnings("unchecked")
+  public <T> Schema<T> schemaFor(T message) {
+    return schemaFor((Class<T>) message.getClass());
+  }
+
+  /**
+   * Registers the given schema for the message type only if a schema was not already registered.
+   *
+   * @param messageType the type of message on which the schema operates.
+   * @param schema the schema for the message type.
+   * @return the previously registered schema, or {@code null} if the given schema was successfully
+   *     registered.
+   */
+  public Schema<?> registerSchema(Class<?> messageType, Schema<?> schema) {
+    checkNotNull(messageType, "messageType");
+    checkNotNull(schema, "schema");
+    return schemaCache.putIfAbsent(messageType, schema);
+  }
+
+  /**
+   * Visible for testing only. Registers the given schema for the message type. If a schema was
+   * previously registered, it will be replaced by the provided schema.
+   *
+   * @param messageType the type of message on which the schema operates.
+   * @param schema the schema for the message type.
+   * @return the previously registered schema, or {@code null} if no schema was registered
+   *     previously.
+   */
+  public Schema<?> registerSchemaOverride(Class<?> messageType, Schema<?> schema) {
+    checkNotNull(messageType, "messageType");
+    checkNotNull(schema, "schema");
+    return schemaCache.put(messageType, schema);
+  }
+
+  private Protobuf() {
+    // TODO(nathanmittler): Detect the proper factory for the platform.
+    SchemaFactory factory = null;
+    for (String className :
+        new String[] {
+          "com.google.frameworks.protobuf.experimental.android.schema.AndroidProto3SchemaFactory",
+          // TODO(nathanmittler): Remove this once the code has been completely ported over.
+          "com.google.frameworks.protobuf.experimental.schema.generic.Proto3SchemaFactory",
+          "com.google.protobuf.Proto3SchemaFactory"
+        }) {
+      factory = newSchemaFactory(className);
+      if (factory != null) {
+        break;
+      }
+    }
+    if (factory == null) {
+      throw new IllegalStateException("Unable to locate a default SchemaFactory. Check classpath.");
+    }
+    schemaFactory = factory;
+  }
+
+  private static SchemaFactory newSchemaFactory(String className) {
+    try {
+      return (SchemaFactory) Class.forName(className).getConstructor().newInstance();
+    } catch (Throwable e) {
+      return null;
+    }
+  }
+}