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https://issues.apache.org/jira/browse/THRIFT-4381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16252682#comment-16252682
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Jens Geyer edited comment on THRIFT-4381 at 11/14/17 11:32 PM:
---------------------------------------------------------------
As I said, this is by design.
Key to understanding and to get what you want is the term
["requiredness"|https://thrift.apache.org/docs/idl]. With Thrift, we have
three, while only two of them actually have a keyword assigned, the third one
is implicitly used if you don't say anything else. Here's an example:
{code}
struct custom {
1: /*default*/ i32 default_field
2: optional i32 optional_field
3: required i32 required_field
}
{code}
The semantics w/regard to read and write are different for all three:
* {{optional}} is only read and written when there is a value assigned. This
is checked via the "isset" bit flags.
* {{required}} fields are, big surprise, required and thus are always written
and read.
* If neither {{optional}} nor {{required}} is specified, the so-called
"default" requiredness takes over.
In that latter case of "default", values are only read when they are on the
wire, but *always* written. So "default" is kind of a mix between {{optional}}
and {{required}}: On write, values are always written like {{required}}
(unlesss they are {{null}} pointers, which integers and most other primitives
aren't) but {{optional}} on read.
*Consequently, the solution in your case is to specify {{optional}} before the
field type.*
Here's the Java code of the {{write()}} method generated from the IDL example
above:
{code}
public void write(org.apache.thrift.protocol.TProtocol oprot, custom
struct) throws org.apache.thrift.TException {
struct.validate();
oprot.writeStructBegin(STRUCT_DESC);
oprot.writeFieldBegin(DEFAULT_FIELD_FIELD_DESC);
oprot.writeI32(struct.default_field);
oprot.writeFieldEnd();
if (struct.isSetOptional_field()) {
oprot.writeFieldBegin(OPTIONAL_FIELD_FIELD_DESC);
oprot.writeI32(struct.optional_field);
oprot.writeFieldEnd();
}
oprot.writeFieldBegin(REQUIRED_FIELD_FIELD_DESC);
oprot.writeI32(struct.required_field);
oprot.writeFieldEnd();
oprot.writeFieldStop();
oprot.writeStructEnd();
}
}
{code}
was (Author: jensg):
As I said, this is by design.
Key to understanding and to get what you want is the term "requiredness". With
Thrift, we have three, while only two of them actually have a keyword assigned,
the third one is implicitly used if you don't say anything else. Here's an
example:
{code}
struct custom {
1: /*default*/ i32 default_field
2: optional i32 optional_field
3: required i32 required_field
}
{code}
The semantics w/regard to read and write are different for all three:
* {{optional}} is only read and written when there is a value assigned. This
is checked via the "isset" bit flags.
* {{required}} fields are, big surprise, required and thus are always written
and read.
* If neither {{optional}} nor {{required}} is specified, the so-called
"default" requiredness takes over.
In that latter case of "default", values are only read when they are on the
wire, but *always* written. So "default" is kind of a mix between {{optional}}
and {{required}}: On write, values are always written like {{required}}
(unlesss they are {{null}} pointers, which integers and most other primitives
aren't) but {{optional}} on read.
*Consequently, the solution in your case is to specify {{optional}} before the
field type.*
Here's the Java code of the {{write()}} method generated from the IDL example
above:
{code}
public void write(org.apache.thrift.protocol.TProtocol oprot, custom
struct) throws org.apache.thrift.TException {
struct.validate();
oprot.writeStructBegin(STRUCT_DESC);
oprot.writeFieldBegin(DEFAULT_FIELD_FIELD_DESC);
oprot.writeI32(struct.default_field);
oprot.writeFieldEnd();
if (struct.isSetOptional_field()) {
oprot.writeFieldBegin(OPTIONAL_FIELD_FIELD_DESC);
oprot.writeI32(struct.optional_field);
oprot.writeFieldEnd();
}
oprot.writeFieldBegin(REQUIRED_FIELD_FIELD_DESC);
oprot.writeI32(struct.required_field);
oprot.writeFieldEnd();
oprot.writeFieldStop();
oprot.writeStructEnd();
}
}
{code}
> Wrong isset bitfield value after transmission
> ---------------------------------------------
>
> Key: THRIFT-4381
> URL: https://issues.apache.org/jira/browse/THRIFT-4381
> Project: Thrift
> Issue Type: Bug
> Components: Java - Library
> Affects Versions: 0.10.0
> Environment: Linux Arch / Oracle JDK v1.8.0u152
> and
> Windows 7 / Oracle JDK v1.8.0u151
> Reporter: Nicolas V.
> Assignee: Jens Geyer
> Labels: newbie, usability
> Fix For: 0.11.0
>
>
> The bitfield field is set to true for every field after deserialization of a
> Thrift message structure.
> Here is a simple test program :
> {code:java}
> public class BitFieldTest
> {
> public static void main(String[] args) throws TException
> {
> final CBChannel chan = new CBChannel();
> chan.setId(42L);
> chan.setName("test");
> // should return true, true, false
> System.out.println("id is set ? " + chan.isSetId());
> System.out.println("name is set ? " + chan.isSetName());
> System.out.println("duration max is set ? " +
> chan.isSetDurationMax());
> final TProtocolFactory protoFactory = new
> TCompactProtocol.Factory();
> final byte[] buf = new
> TSerializer(protoFactory).serialize(chan);
> System.out.println("\n---- Hexdump serialized message : ----\n"
> + HexTools.toHexString(buf));
> final CBChannel chanDst = new CBChannel();
> new TDeserializer(protoFactory).deserialize(chanDst, buf);
> System.out.println("---- toString() of deserialized api msg :
> ----\n" + chanDst);
> // should return true, true, false
> System.out.println("\nid is set ? " + chanDst.isSetId());
> System.out.println("name is set ? " + chanDst.isSetName());
> System.out.println("duration max is set ? " +
> chanDst.isSetDurationMax());
> }
> }
> {code}
> The output is :
> {noformat}
> id is set ? true
> name is set ? true
> duration max is set ? false
> ---- Hexdump serialized message : ----
> 00 16 54 18 04 74 65 73 74 12 26 00 16 00 16 00 16 .T..test.&......
> 10 00 16 00 16 00 16 00 00 ........
> ---- toString() of deserialized api msg : ----
> CBChannel(id:42, name:test, enabled:false, type:null, durationMin:0,
> durationMax:0, inactivityAlarm:0, analogicConfiguration:0,
> digitalConfiguration:0, voipConfiguration:0, r17Index:0, group:null)
> id is set ? true
> name is set ? true
> duration max is set ? true
> {noformat}
> You can see that the last test for is set on the durationMax field return
> true, when it sould return false.
> Here is the idl file :
> {code:java}
> enum ChannelType
> {
> ANALOGIC
> DIGITAL
> VOIP
> }
> struct CBChannelGroup
> {
> 1: i64 id;
> 2: i64 parentId;
> 3: string name;
> }
> struct CBChannel
> {
> 1: i64 id;
> 2: string name;
> 3: bool enabled;
> 4: ChannelType type;
> 5: i64 durationMin;
> 6: i64 durationMax;
> 7: i64 inactivityAlarm;
> 8: i64 analogicConfiguration;
> 9: i64 digitalConfiguration;
> 10: i64 voipConfiguration;
> 11: i64 r17Index;
> 12: CBChannelGroup group;
> }
> {code}
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