1 files changed, 158 insertions, 0 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/MessageInfo.java b/java/core/src/main/java/com/google/protobuf/MessageInfo.java
new file mode 100644
index 00000000..fdcfc2d8
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/MessageInfo.java
@@ -0,0 +1,158 @@
+// 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.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Information for the layout of a protobuf message class. This describes all of the fields
+ * contained within a message.
+ */
+@ExperimentalApi
+public final class MessageInfo {
+  private final ProtoSyntax syntax;
+  private final boolean messageSetWireFormat;
+  private final List<FieldInfo> fields;
+
+  /**
+   * Constructor.
+   *
+   * @param fields the set of fields for the message.
+   */
+  private MessageInfo(ProtoSyntax syntax, boolean messageSetWireFormat, List<FieldInfo> fields) {
+    this.syntax = syntax;
+    this.messageSetWireFormat = messageSetWireFormat;
+    this.fields = fields;
+  }
+
+  /** Gets the syntax for the message (e.g. PROTO2, PROTO3). */
+  public ProtoSyntax getSyntax() {
+    return syntax;
+  }
+
+  /** Indicates whether or not the message should be represented with message set wire format. */
+  public boolean isMessageSetWireFormat() {
+    return messageSetWireFormat;
+  }
+
+  /**
+   * Gets the information for all fields within this message, sorted in ascending order by their
+   * field number.
+   */
+  public List<FieldInfo> getFields() {
+    return fields;
+  }
+
+  /** Creates a new map of field number to message class for message fields. */
+  public Int2ObjectHashMap<Class<?>> messageFieldClassMap() {
+    Int2ObjectHashMap<Class<?>> classMap = new Int2ObjectHashMap<Class<?>>();
+    for (int i = 0; i < fields.size(); ++i) {
+      FieldInfo fd = fields.get(i);
+      int fieldNumber = fd.getFieldNumber();
+
+      // Configure messages
+      switch (fd.getType()) {
+        case MESSAGE:
+          classMap.put(fieldNumber, fd.getField().getType());
+          break;
+        case MESSAGE_LIST:
+          classMap.put(fieldNumber, fd.getListElementType());
+          break;
+        case GROUP:
+          classMap.put(fieldNumber, fd.getField().getType());
+          break;
+        case GROUP_LIST:
+          classMap.put(fieldNumber, fd.getListElementType());
+          break;
+        default:
+          break;
+      }
+    }
+    return classMap;
+  }
+
+  /** Helper method for creating a new builder for {@link MessageInfo}. */
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  /** Helper method for creating a new builder for {@link MessageInfo}. */
+  public static Builder newBuilder(int numFields) {
+    return new Builder(numFields);
+  }
+
+  /** A builder of {@link MessageInfo} instances. */
+  public static final class Builder {
+    private final ArrayList<FieldInfo> fields;
+    private ProtoSyntax syntax;
+    private boolean wasBuilt;
+    private boolean messageSetWireFormat;
+
+    public Builder() {
+      fields = new ArrayList<FieldInfo>();
+    }
+
+    public Builder(int numFields) {
+      fields = new ArrayList<FieldInfo>(numFields);
+    }
+
+    public void withSyntax(ProtoSyntax syntax) {
+      this.syntax = checkNotNull(syntax, "syntax");
+    }
+
+    public void withMessageSetWireFormat(boolean messageSetWireFormat) {
+      this.messageSetWireFormat = messageSetWireFormat;
+    }
+
+    public void add(FieldInfo field) {
+      if (wasBuilt) {
+        throw new IllegalStateException("Builder can only build once");
+      }
+      fields.add(field);
+    }
+
+    public MessageInfo build() {
+      if (wasBuilt) {
+        throw new IllegalStateException("Builder can only build once");
+      }
+      if (syntax == null) {
+        throw new IllegalStateException("Must specify a proto syntax");
+      }
+      wasBuilt = true;
+      Collections.sort(fields);
+      return new MessageInfo(syntax, messageSetWireFormat, Collections.unmodifiableList(fields));
+    }
+  }
+}