import com.google.protos.ipc.invalidation.ClientProtocol.ProtocolVersion; //导入依赖的package包/类
/** Returns whether {@code field} is present in {@code message}. */
@Override
@SuppressWarnings("unchecked")
public boolean hasField(MessageLite rawMessage, Descriptor field) {
  Preconditions.checkNotNull(rawMessage);
  Preconditions.checkNotNull(field);
  ProtocolVersion message = (ProtocolVersion) rawMessage;
  if (field == VERSION) {
    return message.hasVersion();
  }
  throw new IllegalArgumentException("Bad descriptor: " + field);
}
 

import com.google.protos.ipc.invalidation.ClientProtocol.ProtocolVersion; //导入依赖的package包/类
/** Returns the {@code field} from {@code message}. */
@Override
@SuppressWarnings("unchecked")
public Object getField(MessageLite rawMessage, Descriptor field) {
  Preconditions.checkNotNull(rawMessage);
  Preconditions.checkNotNull(field);
  ProtocolVersion message = (ProtocolVersion) rawMessage;
  if (field == VERSION) {
    return message.getVersion();
  }
  throw new IllegalArgumentException("Bad descriptor: " + field);
}
 

import com.google.protos.ipc.invalidation.ClientProtocol.ProtocolVersion; //导入依赖的package包/类
public static TextBuilder toCompactString(TextBuilder builder,
    ProtocolVersion protocolVersion) {
  if (protocolVersion == null) {
    return builder;
  }
  builder.appendFormat("%d.%d", protocolVersion.getVersion().getMajorVersion(),
      protocolVersion.getVersion().getMinorVersion());
  return builder;
}