Search Results

Search found 268 results on 11 pages for 'rem'.

Page 10/11 | < Previous Page | 6 7 8 9 10 11  | Next Page >

• Working with Analytic Workflow Manager (AWM) - Part 8 Cube Metadata Analysis

  - by Mohan Ramanuja

  CUBE SIZEselect dbal.owner||'.'||substr(dbal.table_name,4) awname, sum(dbas.bytes)/1024/1024 as mb, dbas.tablespace_name from dba_lobs dbal, dba_segments dbas where dbal.column_name = 'AWLOB' and dbal.segment_name = dbas.segment_name group by dbal.owner, dbal.table_name, dbas.tablespace_name order by dbal.owner, dbal.table_name SESSION RESOURCES select vses.username||':'||vsst.sid username, vstt.name, max(vsst.value) valuefrom v$sesstat vsst, v$statname vstt, v$session vseswhere vstt.statistic# = vsst.statistic# and vsst.sid = vses.sid andVSES.USERNAME LIKE ('ATTRIBDW_OWN') ANDvstt.name in ('session pga memory', 'session pga memory max', 'session uga memory','session uga memory max', 'session cursor cache count', 'session cursor cache hits', 'session stored procedure space', 'opened cursors current', 'opened cursors cumulative') andvses.username is not null group by vsst.sid, vses.username, vstt.name order by vsst.sid, vses.username, vstt.name OLAP PGA USE select 'OLAP Pages Occupying: '|| round((((select sum(nvl(pool_size,1)) from v$aw_calc)) / (select value from v$pgastat where name = 'total PGA inuse')),2)*100||'%' info from dual union select 'Total PGA Inuse Size: '||value/1024||' KB' info from v$pgastat where name = 'total PGA inuse' union select 'Total OLAP Page Size: '|| round(sum(nvl(pool_size,1))/1024,0)||' KB' info from v$aw_calc order by info desc OLAP PGA USAGE PER USER select vs.username, vs.sid, round(pga_used_mem/1024/1024,2)||' MB' pga_used, round(pga_max_mem/1024/1024,2)||' MB' pga_max, round(pool_size/1024/1024,2)||' MB' olap_pp, round(100*(pool_hits-pool_misses)/pool_hits,2) || '%' olap_ratio from v$process vp, v$session vs, v$aw_calc va where session_id=vs.sid and addr = paddr CUBE LOADING SCRIPT REM The 'set define off' statement is needed only if running this script through SQLPlus.REM If you are using another tool to run this script, the line below may be commented out.set define offBEGIN  DBMS_CUBE.BUILD(    'VALIDATE  ATTRIBDW_OWN.CURRENCY USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.ACCOUNT USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.DATEDIM USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.CUSIP USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.ACCOUNTRETURN',    'CCCCC', -- refresh methodfalse, -- refresh after errors    0, -- parallelismtrue, -- atomic refreshtrue, -- automatic orderfalse); -- add dimensionsEND;/BEGIN  DBMS_CUBE.BUILD(    '  ATTRIBDW_OWN.CURRENCY USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.ACCOUNT USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.DATEDIM USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.CUSIP USING  (    LOAD NO SYNCH,    COMPILE SORT  ),  ATTRIBDW_OWN.ACCOUNTRETURN',    'CCCCC', -- refresh methodfalse, -- refresh after errors    0, -- parallelismtrue, -- atomic refreshtrue, -- automatic orderfalse); -- add dimensionsEND;/ VISUALIZATION OBJECT - AW$ATTRIBDW_OWN  CREATE TABLE "ATTRIBDW_OWN"."AW$ATTRIBDW_OWN"        (            "PS#"    NUMBER(10,0),            "GEN#"   NUMBER(10,0),            "EXTNUM" NUMBER(8,0),            "AWLOB" BLOB,            "OBJNAME"  VARCHAR2(256 BYTE),            "PARTNAME" VARCHAR2(256 BYTE)        )        PCTFREE 10 PCTUSED 40 INITRANS 4 MAXTRANS 255 STORAGE        (            BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT        )        TABLESPACE "ATTRIBDW_DATA" LOB        (            "AWLOB"        )        STORE AS SECUREFILE        (            TABLESPACE "ATTRIBDW_DATA" DISABLE STORAGE IN ROW CHUNK 8192 RETENTION MIN 1 CACHE NOCOMPRESS KEEP_DUPLICATES STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)        )        PARTITION BY RANGE        (            "GEN#"        )        SUBPARTITION BY HASH        (            "PS#",            "EXTNUM"        )        SUBPARTITIONS 8        (            PARTITION "PTN1" VALUES LESS THAN (1) PCTFREE 10 PCTUSED 40 INITRANS 4 MAXTRANS 255 STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" LOB ("AWLOB") STORE AS SECUREFILE ( TABLESPACE "ATTRIBDW_DATA" DISABLE STORAGE IN ROW CHUNK 8192 RETENTION MIN 1 CACHE READS LOGGING NOCOMPRESS KEEP_DUPLICATES STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)) ( SUBPARTITION "SYS_SUBP661" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP662" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP663" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP664" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP665" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION            "SYS_SUBP666" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP667" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP668" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" ) ,            PARTITION "PTNN" VALUES LESS THAN (MAXVALUE) PCTFREE 10 PCTUSED 40 INITRANS 4 MAXTRANS 255 STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" LOB ("AWLOB") STORE AS SECUREFILE ( TABLESPACE "ATTRIBDW_DATA" DISABLE STORAGE IN ROW CHUNK 8192 RETENTION MIN 1 CACHE NOCOMPRESS KEEP_DUPLICATES STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)) ( SUBPARTITION "SYS_SUBP669" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP670" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP671" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP672" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP673" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION            "SYS_SUBP674" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP675" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_SUBP676" LOB ("AWLOB") STORE AS ( TABLESPACE "ATTRIBDW_DATA" ) TABLESPACE "ATTRIBDW_DATA" )        ) ;CREATE UNIQUE INDEX "ATTRIBDW_OWN"."ATTRIBDW_OWN_I$" ON "ATTRIBDW_OWN"."AW$ATTRIBDW_OWN"    (        "PS#", "GEN#", "EXTNUM"    )    PCTFREE 10 INITRANS 4 MAXTRANS 255 COMPUTE STATISTICS STORAGE    (        INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT    )    TABLESPACE "ATTRIBDW_DATA" ;CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000406980C00004$$" ON "ATTRIBDW_OWN"."AW$ATTRIBDW_OWN"    (        PCTFREE 10 INITRANS 1 MAXTRANS 255 STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" LOCAL (PARTITION "SYS_IL_P711" PCTFREE 10 INITRANS 1 MAXTRANS 255 STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) ( SUBPARTITION "SYS_IL_SUBP695" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP696" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP697" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP698" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP699" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP700" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP701" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP702" TABLESPACE "ATTRIBDW_DATA" ) , PARTITION "SYS_IL_P712" PCTFREE 10 INITRANS 1 MAXTRANS 255 STORAGE( BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) ( SUBPARTITION "SYS_IL_SUBP703" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP704" TABLESPACE        "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP705" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP706" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP707" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP708" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP709" TABLESPACE "ATTRIBDW_DATA" , SUBPARTITION "SYS_IL_SUBP710" TABLESPACE "ATTRIBDW_DATA" ) ) PARALLEL (DEGREE 0 INSTANCES 0) ; CUBE BUILD LOG  CREATE TABLE "ATTRIBDW_OWN"."CUBE_BUILD_LOG"        (            "BUILD_ID"          NUMBER,            "SLAVE_NUMBER"      NUMBER,            "STATUS"            VARCHAR2(10 BYTE),            "COMMAND"           VARCHAR2(25 BYTE),            "BUILD_OBJECT"      VARCHAR2(30 BYTE),            "BUILD_OBJECT_TYPE" VARCHAR2(10 BYTE),            "OUTPUT" CLOB,            "AW"            VARCHAR2(30 BYTE),            "OWNER"         VARCHAR2(30 BYTE),            "PARTITION"     VARCHAR2(50 BYTE),            "SCHEDULER_JOB" VARCHAR2(100 BYTE),            "TIME" TIMESTAMP (6)WITH TIME ZONE,        "BUILD_SCRIPT" CLOB,        "BUILD_TYPE"            VARCHAR2(22 BYTE),        "COMMAND_DEPTH"         NUMBER(2,0),        "BUILD_SUB_OBJECT"      VARCHAR2(30 BYTE),        "REFRESH_METHOD"        VARCHAR2(1 BYTE),        "SEQ_NUMBER"            NUMBER,        "COMMAND_NUMBER"        NUMBER,        "IN_BRANCH"             NUMBER(1,0),        "COMMAND_STATUS_NUMBER" NUMBER,        "BUILD_NAME"            VARCHAR2(100 BYTE)        )        SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING STORAGE        (            INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT        )        TABLESPACE "ATTRIBDW_DATA" LOB        (            "OUTPUT"        )        STORE AS BASICFILE        (            TABLESPACE "ATTRIBDW_DATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE LOGGING STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)        )        LOB        (            "BUILD_SCRIPT"        )        STORE AS BASICFILE        (            TABLESPACE "ATTRIBDW_DATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE LOGGING STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)        ) ;CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000407294C00013$$" ON "ATTRIBDW_OWN"."CUBE_BUILD_LOG"    (        PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" PARALLEL (DEGREE 0 INSTANCES 0) ;CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000407294C00007$$" ON "ATTRIBDW_OWN"."CUBE_BUILD_LOG" ( PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" PARALLEL (DEGREE 0 INSTANCES 0) ; CUBE DIMENSION COMPILE  CREATE TABLE "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"        (            "ID"               NUMBER,            "SEQ_NUMBER"       NUMBER,            "ERROR#"           NUMBER(8,0) NOT NULL ENABLE,            "ERROR_MESSAGE"    VARCHAR2(2000 BYTE),            "DIMENSION"        VARCHAR2(100 BYTE),            "DIMENSION_MEMBER" VARCHAR2(100 BYTE),            "MEMBER_ANCESTOR"  VARCHAR2(100 BYTE),            "HIERARCHY1"       VARCHAR2(100 BYTE),            "HIERARCHY2"       VARCHAR2(100 BYTE),            "ERROR_CONTEXT" CLOB        )        SEGMENT CREATION DEFERRED PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING TABLESPACE "ATTRIBDW_DATA" LOB        (            "ERROR_CONTEXT"        )        STORE AS BASICFILE        (            TABLESPACE "ATTRIBDW_DATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE LOGGING        ) ;COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."ID"IS    'Current operation ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."SEQ_NUMBER"IS    'Cube build log sequence number';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."ERROR#"IS    'Error number being reported';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."ERROR_MESSAGE"IS    'Error text being reported';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."DIMENSION"IS    'Name of dimension being compiled';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."DIMENSION_MEMBER"IS    'Problem dimension member';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."MEMBER_ANCESTOR"IS    'Problem dimension member''s parent';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."HIERARCHY1"IS    'First hierarchy involved in error';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."HIERARCHY2"IS    'Second hierarchy involved in error';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"."ERROR_CONTEXT"IS    'Extra information for error';    COMMENT ON TABLE "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"IS    'Cube dimension compile log';CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000407307C00010$$" ON "ATTRIBDW_OWN"."CUBE_DIMENSION_COMPILE"    (        PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE( INITIAL 1048576 NEXT 1048576 MAXEXTENTS 2147483645) TABLESPACE "ATTRIBDW_DATA" PARALLEL (DEGREE 0 INSTANCES 0) ; CUBE OPERATING LOG  CREATE TABLE "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"        (            "INST_ID"    NUMBER NOT NULL ENABLE,            "SID"        NUMBER NOT NULL ENABLE,            "SERIAL#"    NUMBER NOT NULL ENABLE,            "USER#"      NUMBER NOT NULL ENABLE,            "SQL_ID"     VARCHAR2(13 BYTE),            "JOB"        NUMBER,            "ID"         NUMBER,            "PARENT_ID"  NUMBER,            "SEQ_NUMBER" NUMBER,            "TIME" TIMESTAMP (6)WITH TIME ZONE NOT NULL ENABLE,        "LOG_LEVEL"    NUMBER(4,0) NOT NULL ENABLE,        "DEPTH"        NUMBER(4,0),        "OPERATION"    VARCHAR2(15 BYTE) NOT NULL ENABLE,        "SUBOPERATION" VARCHAR2(20 BYTE),        "STATUS"       VARCHAR2(10 BYTE) NOT NULL ENABLE,        "NAME"         VARCHAR2(20 BYTE) NOT NULL ENABLE,        "VALUE"        VARCHAR2(4000 BYTE),        "DETAILS" CLOB        )        SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING STORAGE        (            INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT        )        TABLESPACE "ATTRIBDW_DATA" LOB        (            "DETAILS"        )        STORE AS BASICFILE        (            TABLESPACE "ATTRIBDW_DATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE LOGGING STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)        ) ;COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."INST_ID"IS    'Instance ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."SID"IS    'Session ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."SERIAL#"IS    'Session serial#';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."USER#"IS    'User ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."SQL_ID"IS    'Executing SQL statement ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."JOB"IS    'Identifier of job';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."ID"IS    'Current operation ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."PARENT_ID"IS    'Parent operation ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."SEQ_NUMBER"IS    'Cube build log sequence number';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."TIME"IS    'Time of record';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."LOG_LEVEL"IS    'Verbosity level of record';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."DEPTH"IS    'Nesting depth of record';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."OPERATION"IS    'Current operation';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."SUBOPERATION"IS    'Current suboperation';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."STATUS"IS    'Status of current operation';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."NAME"IS    'Name of record';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."VALUE"IS    'Value of record';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"."DETAILS"IS    'Extra information for record';    COMMENT ON TABLE "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"IS    'Cube operations log';CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000407301C00018$$" ON "ATTRIBDW_OWN"."CUBE_OPERATIONS_LOG"    (        PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" PARALLEL (DEGREE 0 INSTANCES 0) ; CUBE REJECTED RECORDS CREATE TABLE "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"        (            "ID"            NUMBER,            "SEQ_NUMBER"    NUMBER,            "ERROR#"        NUMBER(8,0) NOT NULL ENABLE,            "ERROR_MESSAGE" VARCHAR2(2000 BYTE),            "RECORD#"       NUMBER(38,0),            "SOURCE_ROW" ROWID,            "REJECTED_RECORD" CLOB        )        SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING STORAGE        (            INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT        )        TABLESPACE "ATTRIBDW_DATA" LOB        (            "REJECTED_RECORD"        )        STORE AS BASICFILE        (            TABLESPACE "ATTRIBDW_DATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION NOCACHE LOGGING STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)        ) ;COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."ID"IS    'Current operation ID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."SEQ_NUMBER"IS    'Cube build log sequence number';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."ERROR#"IS    'Error number being reported';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."ERROR_MESSAGE"IS    'Error text being reported';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."RECORD#"IS    'Rejected record number';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."SOURCE_ROW"IS    'Rejected record''s ROWID';    COMMENT ON COLUMN "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"."REJECTED_RECORD"IS    'Rejected record copy';    COMMENT ON TABLE "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"IS    'Cube rejected records log';CREATE UNIQUE INDEX "ATTRIBDW_OWN"."SYS_IL0000407304C00007$$" ON "ATTRIBDW_OWN"."CUBE_REJECTED_RECORDS"    (        PCTFREE 10 INITRANS 2 MAXTRANS 255 STORAGE(INITIAL 1048576 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) TABLESPACE "ATTRIBDW_DATA" PARALLEL (DEGREE 0 INSTANCES 0) ;

  Read the article

• C# 5 Async, Part 3: Preparing Existing code For Await

  - by Reed

  While the Visual Studio Async CTP provides a fantastic model for asynchronous programming, it requires code to be implemented in terms of Task and Task<T>.  The CTP adds support for Task-based asynchrony to the .NET Framework methods, and promises to have these implemented directly in the framework in the future.  However, existing code outside the framework will need to be converted to using the Task class prior to being usable via the CTP. Wrapping existing asynchronous code into a Task or Task<T> is, thankfully, fairly straightforward.  There are two main approaches to this. Code written using the Asynchronous Programming Model (APM) is very easy to convert to using Task<T>.  The TaskFactory class provides the tools to directly convert APM code into a method returning a Task<T>.  This is done via the FromAsync method.  This method takes the BeginOperation and EndOperation methods, as well as any parameters and state objects as arguments, and returns a Task<T> directly. For example, we could easily convert the WebRequest BeginGetResponse and EndGetResponse methods into a method which returns a Task<WebResponse> via: Task<WebResponse> task = Task.Factory .FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Event-based Asynchronous Pattern (EAP) code can also be wrapped into a Task<T>, though this requires a bit more effort than the one line of code above.  This is handled via the TaskCompletionSource<T> class.  MSDN provides a detailed example of using this to wrap an EAP operation into a method returning Task<T>.  It demonstrates handling cancellation and exception handling as well as the basic operation of the asynchronous method itself. The basic form of this operation is typically: Task<YourResult> GetResultAsync() { var tcs = new TaskCompletionSource<YourResult>(); // Handle the event, and setup the task results... this.GetResultCompleted += (o,e) => { if (e.Error != null) tcs.TrySetException(e.Error); else if (e.Cancelled) tcs.TrySetCanceled(); else tcs.TrySetResult(e.Result); }; // Call the asynchronous method this.GetResult(); // Return the task from the TaskCompletionSource return tcs.Task; } We can easily use these methods to wrap our own code into a method that returns a Task<T>.  Existing libraries which cannot be edited can be extended via Extension methods.  The CTP uses this technique to add appropriate methods throughout the framework. The suggested naming for these methods is to define these methods as “Task<YourResult> YourClass.YourOperationAsync(…)”.  However, this naming often conflicts with the default naming of the EAP.  If this is the case, the CTP has standardized on using “Task<YourResult> YourClass.YourOperationTaskAsync(…)”. Once we’ve wrapped all of our existing code into operations that return Task<T>, we can begin investigating how the Async CTP can be used with our own code.

  Read the article

• ConcurrentDictionary<TKey,TValue> used with Lazy<T>

  - by Reed

  In a recent thread on the MSDN forum for the TPL, Stephen Toub suggested mixing ConcurrentDictionary<T,U> with Lazy<T>.  This provides a fantastic model for creating a thread safe dictionary of values where the construction of the value type is expensive.  This is an incredibly useful pattern for many operations, such as value caches. The ConcurrentDictionary<TKey, TValue> class was added in .NET 4, and provides a thread-safe, lock free collection of key value pairs.  While this is a fantastic replacement for Dictionary<TKey, TValue>, it has a potential flaw when used with values where construction of the value class is expensive. The typical way this is used is to call a method such as GetOrAdd to fetch or add a value to the dictionary.  It handles all of the thread safety for you, but as a result, if two threads call this simultaneously, two instances of TValue can easily be constructed. If TValue is very expensive to construct, or worse, has side effects if constructed too often, this is less than desirable.  While you can easily work around this with locking, Stephen Toub provided a very clever alternative – using Lazy<TValue> as the value in the dictionary instead. This looks like the following.  Instead of calling: MyValue value = dictionary.GetOrAdd( key, () => new MyValue(key)); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We would instead use a ConcurrentDictionary<TKey, Lazy<TValue>>, and write: MyValue value = dictionary.GetOrAdd( key, () => new Lazy<MyValue>( () => new MyValue(key))) .Value; This simple change dramatically changes how the operation works.  Now, if two threads call this simultaneously, instead of constructing two MyValue instances, we construct two Lazy<MyValue> instances. However, the Lazy<T> class is very cheap to construct.  Unlike “MyValue”, we can safely afford to construct this twice and “throw away” one of the instances. We then call Lazy<T>.Value at the end to fetch our “MyValue” instance.  At this point, GetOrAdd will always return the same instance of Lazy<MyValue>.  Since Lazy<T> doesn’t construct the MyValue instance until requested, the actual MyClass instance returned is only constructed once.

  Read the article

• Linux Fiber Channel Host Setup Basic

  - by Jim

  I've been googling for about 4 hours now with no luck. I am trying to setup a Linux server running Oracle Server 6.3 as a Fiber Channel host. And then connect it to a Dell Compellent Fibre Channel Host contain a 500GB Volume. The Oracle server itself contains two Brocade 815 FC HBAs. I've discovered their WWN(I think) via cat /sys/class/fc_host/host1/port_name 0x100000051efc3d85 cat /sys/class/fc_host/host2/port_name 0x100000051efc3d9f The next part is where I am at a loss. I've used iSCSI before...is FC the same deal where you have an initiator and a target? If so where do I specific that in linux? I'm also new to Fiber Channel as a protocol, so i am unsure what is needed to make a transaction? WWN and port ID? Similar to IP:Port combination in the Ethernet world. I've read alot regarding using systool, multipath, fc_transport commands, however none of these is recognized as a valid command from Oracle Server 6.3 Appreciate the guidance and assistance. I installed sccsi-target-utils and can now run rescan-scsi-bus and sg_map -x. rescan-scsi-bus.sh -l -w -r Host adapter 0 (megaraid_sas) found. Host adapter 1 ((null)) found. Host adapter 2 ((null)) found. Host adapter 3 (ata_piix) found. Host adapter 4 (ata_piix) found. Scanning SCSI subsystem for new devices and remove devices that have disappeared Scanning host 0 for SCSI target IDs 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15, LUNs 0 1 2 3 4 5 6 7 Scanning for device 0 2 0 0 .... OLD: Host: scsi0 Channel: 02 Id: 00 Lun: 00 Vendor: DELL Model: PERC H700 Rev: 2.30 Type: Direct-Access ANSI SCSI revision: 05 Scanning for device 0 2 1 0 ... OLD: Host: scsi0 Channel: 02 Id: 01 Lun: 00 Vendor: DELL Model: PERC H700 Rev: 2.30 Type: Direct-Access ANSI SCSI revision: 05 Scanning host 1 for all SCSI target IDs, LUNs 0 1 2 3 4 5 6 7 Scanning for device 1 0 3 1 ... OLD: Host: scsi1 Channel: 00 Id: 03 Lun: 01 Vendor: COMPELNT Model: Compellent Vol Rev: 0505 Type: Direct-Access ANSI SCSI revision: 05 Scanning host 2 for all SCSI target IDs, LUNs 0 1 2 3 4 5 6 7 Scanning host 3 for all SCSI target IDs, LUNs 0 1 2 3 4 5 6 7 Scanning for device 3 0 0 0 ... REM: Host: scsi3 Channel: 00 Id: 00 Lun: 00 DEL: Vendor: TEAC Model: DVD-ROM DV-28SW Rev: R.2A Type: CD-ROM ANSI SCSI revision: 05 Scanning host 4 channels 0 for SCSI target IDs 0, LUNs 0 1 2 3 4 5 6 7 0 new device(s) found. 1 device(s) removed. and sg_map -x /dev/sg0 0 0 32 0 13 /dev/sg1 0 2 0 0 0 /dev/sda /dev/sg2 0 2 1 0 0 /dev/sdb /dev/sg4 1 0 3 1 0 /dev/sdc I'm not sure what this all means...

  Read the article

• WinPE, Startnet.CMD and passing variables to second batch file not working

  - by user140892

  I don't know scripting or PowerShell (yes I need to learn something). I'm not an expert batch file maker either. I have a WinPE flash drive which I used to deploy OS images. I have the WIM, drivers and anything needed else outside the WinPE environment to ensure that Updates, changes are easier for me to make. I use the "STARTNET.CMD" batch file which is part of the WinPE. The reason to go through the letter drives is that the WinPE always gets the X letter drive assigned. The flash drive itself can receive a random letter which always changes. My deployment menu is located on the flash drive it self and not inside the WinPE. This is so that if I need to make a change I don't have to re-do the WinPE. I am able to locate the "menu.bat" batch file and launch it. I use a variable to capture the letter drive. I call the second batch file named "menu.bat" and pass the variable to it. When the second batch file loads, I believe that I am calling the variable correctly. If I break out of the batch file I can echo the variable and see the expected reply. The issue is that I can't use the variable to work with anything on the second batch file. In my test, I can get this to work over and over. When it runs from the real USB flash drive it does not work. I removed comments from the second batch file to make it smaller. My issue is that files below all get a message stating that the system cannot find the path specified. Diskpart Imagex.exe bcdboot.exe Why can't I get the varible to properly function when I try to using example "ImageX.exe"? Contents of the Startnet.cmd @echo off for %%p in (a b c d e f g h i j k l m n o p q r s t u v w x y z) do if exist %%p:\Tools\ set w=%%p Set execpatch=%w%\Tools\ call %w%:\Menu.bat \Tools\ Contents of the Menu.BAT @echo off set SecondPath=%1 cls :Start cls Echo. Echo.============================================================== Echo. Windows 7 64 Bit Ent Basic Desktops Echo.============================================================== Echo. Echo A. 790 Windows 7 - Basic Echo. Echo. Echo I. Exit Echo. Echo. set /p choice=Choose your option = if not '%choice%'=='' set choice=%choice:~0,1% if '%choice%'=='a' goto 790_Windows_7_Basic echo "%choice%" is not a valid (answer/command) echo. goto start :790_Windows_7_Basic REM DISKPART /s %SecondPath%BatchFiles\Make-Partition.txt %SecondPath%imagex.exe /apply %SecondPath%Images\Win7-64b-Ent-Basic-SysPreped.wim 1 o:\ /verify %SecondPath%bcdboot.exe o:\Windows /s S: Copy %SecondPath%Unattended\unattend.XML o:\Windows\System32\sysprep\unattend.XML /y xcopy %SecondPath%Drivers\790\*.* o:\Windows\INF\790\ /E /Q /Y MD o:\Windows\Setup\Scripts\ Copy %SecondPath%BatchFiles\SetupComplete.cmd o:\Windows\Setup\Scripts\ /y Goto Done :Done Exit

  Read the article

• CakePHP in a subdirectory using nginx (Rewrite rules?)

  - by lhnz

  I managed to get this to work a while back, but on returning to the cakephp project I had started it seems that whatever changes I've made to nginx recently (or perhaps a recent update) have broken my rewrite rules. Currently I have: worker_processes 1; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; server { listen 80; server_name localhost; location / { root html; index index.php index.html index.htm; } location /basic_cake/ { index index.php; if (-f $request_filename) { break; } if (!-f $request_filename) { rewrite ^/basic_cake/(.+)$ /basic_cake/index.php?url=$1 last; break; } } location /cake_test/ { index index.php; if (-f $request_filename) { break; } if (!-f $request_filename) { rewrite ^/cake_test/(.+)$ /cake_test/index.php?url=$1 last; break; } } # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { root html; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } } server { listen 8081; server_name localhost; root /srv/http/html/xsp; location / { index index.html index.htm index.aspx default.aspx; } location ~ \.(aspx|asmx|ashx|asax|ascx|soap|rem|axd|cs|config|dll)$ { fastcgi_pass 127.0.0.1:9001; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } } } The problem that I have is that the css and images will not load from the webroot. Instead if I visit http://localhost/basic_cake/css/cake.generic.css, I get a page which tells me: CakePHP: the rapid development php framework Missing Controller Error: CssController could not be found. Error: Create the class CssController below in file: app/controllers/css_controller.php var $name = 'Css'; } ? Notice: If you want to customize this error message, create app/views/errors/missing_controller.ctp CakePHP: the rapid development php framework Does anybody have any ideas on how to fix this?

  Read the article

• C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

  - by Reed

  Today’s announcement at PDC of the future directions C# is taking excite me greatly.  The new Visual Studio Async CTP is amazing.  Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability.  This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await. This core of the new asynchronous functionality is built upon three key features.  First is the Task functionality in .NET 4, and based on Task and Task<TResult>.  While Task was intended to be the primary means of asynchronous programming with .NET 4, the .NET Framework was still based mainly on the Asynchronous Pattern and the Event-based Asynchronous Pattern. The .NET Framework added functionality and guidance for wrapping existing APIs into a Task based API, but the framework itself didn’t really adopt Task or Task<TResult> in any meaningful way.  The CTP shows that, going forward, this is changing. One of the three key new features coming in C# is actually a .NET Framework feature.  Nearly every asynchronous API in the .NET Framework has been wrapped into a new, Task-based method calls.  In the CTP, this is done via as external assembly (AsyncCtpLibrary.dll) which uses Extension Methods to wrap the existing APIs.  However, going forward, this will be handled directly within the Framework.  This will have a unifying effect throughout the .NET Framework.  This is the first building block of the new features for asynchronous programming: Going forward, all asynchronous operations will work via a method that returns Task or Task<TResult> The second key feature is the new async contextual keyword being added to the language.  The async keyword is used to declare an asynchronous function, which is a method that either returns void, a Task, or a Task<T>. Inside the asynchronous function, there must be at least one await expression.  This is a new C# keyword (await) that is used to automatically take a series of statements and break it up to potentially use discontinuous evaluation.  This is done by using await on any expression that evaluates to a Task or Task<T>. For example, suppose we want to download a webpage as a string.  There is a new method added to WebClient: Task<string> WebClient.DownloadStringTaskAsync(Uri).  Since this returns a Task<string> we can use it within an asynchronous function.  Suppose, for example, that we wanted to do something similar to my asynchronous Task example – download a web page asynchronously and check to see if it supports XHTML 1.0, then report this into a TextBox.  This could be done like so: private async void button1_Click(object sender, RoutedEventArgs e) { string url = "http://reedcopsey.com"; string content = await new WebClient().DownloadStringTaskAsync(url); this.textBox1.Text = string.Format("Page {0} supports XHTML 1.0: {1}", url, content.Contains("XHTML 1.0")); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Let’s walk through what’s happening here, step by step.  By adding the async contextual keyword to the method definition, we are able to use the await keyword on our WebClient.DownloadStringTaskAsync method call. When the user clicks this button, the new method (Task<string> WebClient.DownloadStringTaskAsync(string)) is called, which returns a Task<string>.  By adding the await keyword, the runtime will call this method that returns Task<string>, and execution will return to the caller at this point.  This means that our UI is not blocked while the webpage is downloaded.  Instead, the UI thread will “await” at this point, and let the WebClient do it’s thing asynchronously. When the WebClient finishes downloading the string, the user interface’s synchronization context will automatically be used to “pick up” where it left off, and the Task<string> returned from DownloadStringTaskAsync is automatically unwrapped and set into the content variable.  At this point, we can use that and set our text box content. There are a couple of key points here: Asynchronous functions are declared with the async keyword, and contain one or more await expressions In addition to the obvious benefits of shorter, simpler code – there are some subtle but tremendous benefits in this approach.  When the execution of this asynchronous function continues after the first await statement, the initial synchronization context is used to continue the execution of this function.  That means that we don’t have to explicitly marshal the call that sets textbox1.Text back to the UI thread – it’s handled automatically by the language and framework!  Exception handling around asynchronous method calls also just works. I’d recommend every C# developer take a look at the documentation on the new Asynchronous Programming for C# and Visual Basic page, download the Visual Studio Async CTP, and try it out.

  Read the article

• Parallelism in .NET – Part 13, Introducing the Task class

  - by Reed

  Once we’ve used a task-based decomposition to decompose a problem, we need a clean abstraction usable to implement the resulting decomposition.  Given that task decomposition is founded upon defining discrete tasks, .NET 4 has introduced a new API for dealing with task related issues, the aptly named Task class. The Task class is a wrapper for a delegate representing a single, discrete task within your decomposition.  We will go into various methods of construction for tasks later, but, when reduced to its fundamentals, an instance of a Task is nothing more than a wrapper around a delegate with some utility functionality added.  In order to fully understand the Task class within the new Task Parallel Library, it is important to realize that a task really is just a delegate – nothing more.  In particular, note that I never mentioned threading or parallelism in my description of a Task.  Although the Task class exists in the new System.Threading.Tasks namespace: Tasks are not directly related to threads or multithreading. Of course, Task instances will typically be used in our implementation of concurrency within an application, but the Task class itself does not provide the concurrency used.  The Task API supports using Tasks in an entirely single threaded, synchronous manner. Tasks are very much like standard delegates.  You can execute a task synchronously via Task.RunSynchronously(), or you can use Task.Start() to schedule a task to run, typically asynchronously.  This is very similar to using delegate.Invoke to execute a delegate synchronously, or using delegate.BeginInvoke to execute it asynchronously. The Task class adds some nice functionality on top of a standard delegate which improves usability in both synchronous and multithreaded environments. The first addition provided by Task is a means of handling cancellation via the new unified cancellation mechanism of .NET 4.  If the wrapped delegate within a Task raises an OperationCanceledException during it’s operation, which is typically generated via calling ThrowIfCancellationRequested on a CancellationToken, or if the CancellationToken used to construct a Task instance is flagged as canceled, the Task’s IsCanceled property will be set to true automatically.  This provides a clean way to determine whether a Task has been canceled, often without requiring specific exception handling. Tasks also provide a clean API which can be used for waiting on a task.  Although the Task class explicitly implements IAsyncResult, Tasks provide a nicer usage model than the traditional .NET Asynchronous Programming Model.  Instead of needing to track an IAsyncResult handle, you can just directly call Task.Wait() to block until a Task has completed.  Overloads exist for providing a timeout, a CancellationToken, or both to prevent waiting indefinitely.  In addition, the Task class provides static methods for waiting on multiple tasks – Task.WaitAll and Task.WaitAny, again with overloads providing time out options.  This provides a very simple, clean API for waiting on single or multiple tasks. Finally, Tasks provide a much nicer model for Exception handling.  If the delegate wrapped within a Task raises an exception, the exception will automatically get wrapped into an AggregateException and exposed via the Task.Exception property.  This exception is stored with the Task directly, and does not tear down the application.  Later, when Task.Wait() (or Task.WaitAll or Task.WaitAny) is called on this task, an AggregateException will be raised at that point if any of the tasks raised an exception.  For example, suppose we have the following code: Task taskOne = new Task( () => { throw new ApplicationException("Random Exception!"); }); Task taskTwo = new Task( () => { throw new ArgumentException("Different exception here"); }); // Start the tasks taskOne.Start(); taskTwo.Start(); try { Task.WaitAll(new[] { taskOne, taskTwo }); } catch (AggregateException e) { Console.WriteLine(e.InnerExceptions.Count); foreach (var inner in e.InnerExceptions) Console.WriteLine(inner.Message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, our routine will print: 2 Different exception here Random Exception! Note that we had two separate tasks, each of which raised two distinctly different types of exceptions.  We can handle this cleanly, with very little code, in a much nicer manner than the Asynchronous Programming API.  We no longer need to handle TargetInvocationException or worry about implementing the Event-based Asynchronous Pattern properly by setting the AsyncCompletedEventArgs.Error property.  Instead, we just raise our exception as normal, and handle AggregateException in a single location in our calling code.

  Read the article

• Parallelism in .NET – Part 16, Creating Tasks via a TaskFactory

  - by Reed

  The Task class in the Task Parallel Library supplies a large set of features.  However, when creating the task, and assigning it to a TaskScheduler, and starting the Task, there are quite a few steps involved.  This gets even more cumbersome when multiple tasks are involved.  Each task must be constructed, duplicating any options required, then started individually, potentially on a specific scheduler.  At first glance, this makes the new Task class seem like more work than ThreadPool.QueueUserWorkItem in .NET 3.5. In order to simplify this process, and make Tasks simple to use in simple cases, without sacrificing their power and flexibility, the Task Parallel Library added a new class: TaskFactory. The TaskFactory class is intended to “Provide support for creating and scheduling Task objects.”  Its entire purpose is to simplify development when working with Task instances.  The Task class provides access to the default TaskFactory via the Task.Factory static property.  By default, TaskFactory uses the default TaskScheduler to schedule tasks on a ThreadPool thread.  By using Task.Factory, we can automatically create and start a task in a single “fire and forget” manner, similar to how we did with ThreadPool.QueueUserWorkItem: Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides us with the same level of simplicity we had with ThreadPool.QueueUserWorkItem, but even more power.  For example, we can now easily wait on the task: // Start our task on a background thread var task = Task.Factory.StartNew(() => this.ExecuteBackgroundWork(myData) ); // Do other work on the main thread, // while the task above executes in the background this.ExecuteWorkSynchronously(); // Wait for the background task to finish task.Wait(); TaskFactory simplifies creation and startup of simple background tasks dramatically. In addition to using the default TaskFactory, it’s often useful to construct a custom TaskFactory.  The TaskFactory class includes an entire set of constructors which allow you to specify the default configuration for every Task instance created by that factory.  This is particularly useful when using a custom TaskScheduler.  For example, look at the sample code for starting a task on the UI thread in Part 15: // Given the following, constructed on the UI thread // TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // When inside a background task, we can do string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); This is actually quite a bit more complicated than necessary.  When we create the uiScheduler instance, we can use that to construct a TaskFactory that will automatically schedule tasks on the UI thread.  To do that, we’d create the following on our main thread, prior to constructing our background tasks: // Construct a task scheduler from the current SynchronizationContext (UI thread) var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Construct a new TaskFactory using our UI scheduler var uiTaskFactory = new TaskFactory(uiScheduler); If we do this, when we’re on a background thread, we can use this new TaskFactory to marshal a Task back onto the UI thread.  Our previous code simplifies to: // When inside a background task, we can do string status = GetUpdatedStatus(); // Update our UI uiTaskFactory.StartNew( () => statusLabel.Text = status); Notice how much simpler this becomes!  By taking advantage of the convenience provided by a custom TaskFactory, we can now marshal to set data on the UI thread in a single, clear line of code!

  Read the article

• Tweaking a few URL validation settings on ASP.NET v4.0

  - by Carlyle Dacosta

  ASP.NET has a few default settings for URLs out of the box. These can be configured quite easily in the web.config file within the  <system.web>/<httpRuntime> configuration section. Some of these are: <httpRuntime maxUrlLength=”<number here>”. This number should be an integer value (defaults to 260 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. This attribute gates the length of the Url without query string. <httpRuntime maxQueryStringLength=”<number here>”. This number should be an integer value (defaults to 2048 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. <httpRuntime requestPathInvalidCharacters=”List of characters you need included in ASP.NETs validation checks”. By default the characters are “<,>,*,%,&,:,\,?”. However once can easily change this by setting by modifying web.config. Remember, these characters can be specified in a variety of formats. For example, I want the character ‘!’ to be included in ASP.NETs URL validation logic. So I set the following: <httpRuntime requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,!”. A character could also be specified in its xml encoded form. ‘&lt;;’ would mean the ‘<’ sign). I could specify the ‘!’ in its xml encoded unicode format such as requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,$#x0021;” or I could specify it in its unicode encoded form or in the “<,>,*,%,&,:,\,?,%u0021” format. The following settings can be applied at Root Web.Config level, App Web.config level, Folder level or within a location tag: <location path="some path here"> <system.web> <httpRuntime maxUrlLength="" maxQueryStringLength="" requestPathInvalidChars="" .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If any of the above settings fail request validation, an Http 400 “Bad Request” HttpException is thrown. These can be easily handled on the Application_Error handler on Global.asax.   Also, a new attribute in <httpRuntime /> called “relaxedUrlToFileSystemMapping” has been added with a default of false. <httpRuntime … relaxedUrlToFileSystemMapping="true|false" /> When the relaxedUrlToFileSystemMapping attribute is set to false inbound Urls still need to be valid NTFS file paths. For example Urls (sans query string) need to be less than 260 characters; no path segment within a Url can use old-style DOS device names (LPT1, COM1, etc…); Urls must be valid Windows file paths. A url like “http://digg.com/http://cnn.com” should work with this attribute set to true (of course a few characters will need to be unblocked by removing them from requestPathInvalidCharacters="" above). Managed configuration for non-NTFS-compliant Urls is determined from the first valid configuration path found when walking up the path segments of the Url. For example, if the request Url is "/foo/bar/baz/<blah>data</blah>", and there is a web.config in the "/foo/bar" directory, then the managed configuration for the request comes from merging the configuration hierarchy to include the web.config from "/foo/bar". The value of the public property HttpRequest.PhysicalPath is set to [physical file path of the application root] + "REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". For example, given a request Url like "/foo/bar/baz/<blah>data</blah>", where the application root is "/foo/bar" and the physical file path for that root is "c:\inetpub\wwwroot\foo\bar", then PhysicalPath would be "c:\inetpub\wwwroot\foo\bar\ REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". Carl Dacosta ASP.NET QA Team

  Read the article

• Tweaking a few URL validation settings on ASP.NET v4.0

  - by Carlyle Dacosta

  ASP.NET has a few default settings for URLs out of the box. These can be configured quite easily in the web.config file within the  <system.web>/<httpRuntime> configuration section. Some of these are: <httpRuntime maxUrlLength=”<number here>” This number should be an integer value (defaults to 260 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. This attribute gates the length of the Url without query string. <httpRuntime maxQueryStringLength=”<number here>”. This number should be an integer value (defaults to 2048 characters). The value must be greater than or equal to zero, though obviously small values will lead to an un-useable website. <httpRuntime requestPathInvalidCharacters=”List of characters you need included in ASP.NETs validation checks” /> By default the characters are “<,>,*,%,&,:,\,?”. However once can easily change this by setting by modifying web.config. Remember, these characters can be specified in a variety of formats. For example, I want the character ‘!’ to be included in ASP.NETs URL validation logic. So I set the following: <httpRuntime requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,!”. A character could also be specified in its xml encoded form. ‘&lt;;’ would mean the ‘<’ sign). I could specify the ‘!’ in its xml encoded unicode format such as requestPathInvalidCharacters=”<,>,*,%,&,:,\,?,$#x0021;” or I could specify it in its unicode encoded form or in the “<,>,*,%,&,:,\,?,%u0021” format. The following settings can be applied at Root Web.Config level, App Web.config level, Folder level or within a location tag: <location path="some path here"> <system.web> <httpRuntime maxUrlLength="" maxQueryStringLength="" requestPathInvalidChars="" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If any of the above settings fail request validation, an Http 400 “Bad Request” HttpException is thrown. These can be easily handled on the Application_Error handler on Global.asax.   Also, a new attribute in <httpRuntime /> called “relaxedUrlToFileSystemMapping” has been added with a default of false. <httpRuntime … relaxedUrlToFileSystemMapping="true|false" /> When the relaxedUrlToFileSystemMapping attribute is set to false inbound Urls still need to be valid NTFS file paths. For example Urls (sans query string) need to be less than 260 characters; no path segment within a Url can use old-style DOS device names (LPT1, COM1, etc…); Urls must be valid Windows file paths. A url like “http://digg.com/http://cnn.com” should work with this attribute set to true (of course a few characters will need to be unblocked by removing them from requestPathInvalidCharacters="" above). Managed configuration for non-NTFS-compliant Urls is determined from the first valid configuration path found when walking up the path segments of the Url. For example, if the request Url is "/foo/bar/baz/<blah>data</blah>", and there is a web.config in the "/foo/bar" directory, then the managed configuration for the request comes from merging the configuration hierarchy to include the web.config from "/foo/bar". The value of the public property HttpRequest.PhysicalPath is set to [physical file path of the application root] + "REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH". For example, given a request Url like "/foo/bar/baz/<blah>data</blah>", where the application root is "/foo/bar" and the physical file path for that root is "c:\inetpub\wwwroot\foo\bar", then PhysicalPath would be "c:\inetpub\wwwroot\foo\bar\ REQUEST_URL_IS_NOT_A_VALID_FILESYSTEM_PATH".

  Read the article

• Parallelism in .NET – Part 8, PLINQ’s ForAll Method

  - by Reed

  Parallel LINQ extends LINQ to Objects, and is typically very similar.  However, as I previously discussed, there are some differences.  Although the standard way to handle simple Data Parellelism is via Parallel.ForEach, it’s possible to do the same thing via PLINQ. PLINQ adds a new method unavailable in standard LINQ which provides new functionality… LINQ is designed to provide a much simpler way of handling querying, including filtering, ordering, grouping, and many other benefits.  Reading the description in LINQ to Objects on MSDN, it becomes clear that the thinking behind LINQ deals with retrieval of data.  LINQ works by adding a functional programming style on top of .NET, allowing us to express filters in terms of predicate functions, for example. PLINQ is, generally, very similar.  Typically, when using PLINQ, we write declarative statements to filter a dataset or perform an aggregation.  However, PLINQ adds one new method, which provides a very different purpose: ForAll. The ForAll method is defined on ParallelEnumerable, and will work upon any ParallelQuery<T>.  Unlike the sequence operators in LINQ and PLINQ, ForAll is intended to cause side effects.  It does not filter a collection, but rather invokes an action on each element of the collection. At first glance, this seems like a bad idea.  For example, Eric Lippert clearly explained two philosophical objections to providing an IEnumerable<T>.ForEach extension method, one of which still applies when parallelized.  The sole purpose of this method is to cause side effects, and as such, I agree that the ForAll method “violates the functional programming principles that all the other sequence operators are based upon”, in exactly the same manner an IEnumerable<T>.ForEach extension method would violate these principles.  Eric Lippert’s second reason for disliking a ForEach extension method does not necessarily apply to ForAll – replacing ForAll with a call to Parallel.ForEach has the same closure semantics, so there is no loss there. Although ForAll may have philosophical issues, there is a pragmatic reason to include this method.  Without ForAll, we would take a fairly serious performance hit in many situations.  Often, we need to perform some filtering or grouping, then perform an action using the results of our filter.  Using a standard foreach statement to perform our action would avoid this philosophical issue: // Filter our collection var filteredItems = collection.AsParallel().Where( i => i.SomePredicate() ); // Now perform an action foreach (var item in filteredItems) { // These will now run serially item.DoSomething(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This would cause a loss in performance, since we lose any parallelism in place, and cause all of our actions to be run serially. We could easily use a Parallel.ForEach instead, which adds parallelism to the actions: // Filter our collection var filteredItems = collection.AsParallel().Where( i => i.SomePredicate() ); // Now perform an action once the filter completes Parallel.ForEach(filteredItems, item => { // These will now run in parallel item.DoSomething(); }); This is a noticeable improvement, since both our filtering and our actions run parallelized.  However, there is still a large bottleneck in place here.  The problem lies with my comment “perform an action once the filter completes”.  Here, we’re parallelizing the filter, then collecting all of the results, blocking until the filter completes.  Once the filtering of every element is completed, we then repartition the results of the filter, reschedule into multiple threads, and perform the action on each element.  By moving this into two separate statements, we potentially double our parallelization overhead, since we’re forcing the work to be partitioned and scheduled twice as many times. This is where the pragmatism comes into play.  By violating our functional principles, we gain the ability to avoid the overhead and cost of rescheduling the work: // Perform an action on the results of our filter collection .AsParallel() .Where( i => i.SomePredicate() ) .ForAll( i => i.DoSomething() ); The ability to avoid the scheduling overhead is a compelling reason to use ForAll.  This really goes back to one of the key points I discussed in data parallelism: Partition your problem in a way to place the most work possible into each task.  Here, this means leaving the statement attached to the expression, even though it causes side effects and is not standard usage for LINQ. This leads to my one guideline for using ForAll: The ForAll extension method should only be used to process the results of a parallel query, as returned by a PLINQ expression. Any other usage scenario should use Parallel.ForEach, instead.

  Read the article

• Parallelism in .NET – Part 17, Think Continuations, not Callbacks

  - by Reed

  In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

  Read the article

• Switching the layout in Orchard CMS

  - by Bertrand Le Roy

  The UI composition in Orchard is extremely flexible, thanks in no small part to the usage of dynamic Clay shapes. Every notable UI construct in Orchard is built as a shape that other parts of the system can then party on and modify any way they want. Case in point today: modifying the layout (which is a shape) on the fly to provide custom page structures for different parts of the site. This might actually end up being built-in Orchard 1.0 but for the moment it’s not in there. Plus, it’s quite interesting to see how it’s done. We are going to build a little extension that allows for specialized layouts in addition to the default layout.cshtml that Orchard understands out of the box. The extension will add the possibility to add the module name (or, in MVC terms, area name) to the template name, or module and controller names, or module, controller and action names. For example, the home page is served by the HomePage module, so with this extension you’ll be able to add an optional layout-homepage.cshtml file to your theme to specialize the look of the home page while leaving all other pages using the regular layout.cshtml. I decided to implement this sample as a theme with code. This way, the new overrides are only enabled as the theme is activated, which makes a lot of sense as this is going to be where you’ll be creating those additional layouts. The first thing I did was to create my own theme, derived from the default TheThemeMachine with this command: codegen theme CustomLayoutMachine /CreateProject:true /IncludeInSolution:true /BasedOn:TheThemeMachine .csharpcode, .csharpcode pre { font-size: 12px; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Once that was done, I worked around a known bug and moved the new project from the Modules solution folder into Themes (the code was already physically in the right place, this is just about Visual Studio editing). The CreateProject flag in the command-line created a project file for us in the theme’s folder. This is only necessary if you want to run code outside of views from that theme. The code that we want to add is the following LayoutFilter.cs: using System.Linq; using System.Web.Mvc; using System.Web.Routing; using Orchard; using Orchard.Mvc.Filters; namespace CustomLayoutMachine.Filters { public class LayoutFilter : FilterProvider, IResultFilter { private readonly IWorkContextAccessor _wca; public LayoutFilter(IWorkContextAccessor wca) { _wca = wca; } public void OnResultExecuting(ResultExecutingContext filterContext) { var workContext = _wca.GetContext(); var routeValues = filterContext.RouteData.Values; workContext.Layout.Metadata.Alternates.Add( BuildShapeName(routeValues, "area")); workContext.Layout.Metadata.Alternates.Add( BuildShapeName(routeValues, "area", "controller")); workContext.Layout.Metadata.Alternates.Add( BuildShapeName(routeValues, "area", "controller", "action")); } public void OnResultExecuted(ResultExecutedContext filterContext) { } private static string BuildShapeName( RouteValueDictionary values, params string[] names) { return "Layout__" + string.Join("__", names.Select(s => ((string)values[s] ?? "").Replace(".", "_"))); } } } This filter is intercepting ResultExecuting, which is going to provide a context object out of which we can extract the route data. We are also injecting an IWorkContextAccessor dependency that will give us access to the current Layout object, so that we can add alternate shape names to its metadata. We are adding three possible shape names to the default, with different combinations of area, controller and action names. For example, a request to a blog post is going to be routed to the “Orchard.Blogs” module’s “BlogPost” controller’s “Item” action. Our filters will then add the following shape names to the default “Layout”: Layout__Orchard_Blogs Layout__Orchard_Blogs__BlogPost Layout__Orchard_Blogs__BlogPost__Item Those template names get mapped into the following file names by the system (assuming the Razor view engine): Layout-Orchard_Blogs.cshtml Layout-Orchard_Blogs-BlogPost.cshtml Layout-Orchard_Blogs-BlogPost-Item.cshtml This works for any module/controller/action of course, but in the sample I created Layout-HomePage.cshtml (a specific layout for the home page), Layout-Orchard_Blogs.cshtml (a layout for all the blog views) and Layout-Orchard_Blogs-BlogPost-Item.cshtml (a layout that is specific to blog posts). Of course, this is just an example, and this kind of dynamic extension of shapes that you didn’t even create in the first place is highly encouraged in Orchard. You don’t have to do it from a filter, we only did it this way because that was a good place where we could get the context that we needed. And of course, you can base your alternate shape names on something completely different from route values if you want. For example, you might want to create your own part that modifies the layout for a specific content item, or you might want to do it based on the raw URL (like it’s done in widget rules) or who knows what crazy custom rule. The point of all this is to show that extending or modifying shapes is easy, and the layout just happens to be a shape. In other words, you can do whatever you want. Ain’t that nice? The custom theme can be found here: Orchard.Theme.CustomLayoutMachine.1.0.nupkg Many thanks to Louis, who showed me how to do this.

  Read the article

• Dynamically switching the theme in Orchard

  - by Bertrand Le Roy

  It may sound a little puzzling at first, but in Orchard CMS, more than one theme can be active at any given time. The reason for that is that we have an extensibility point that allows a module (or a theme) to participate in the choice of the theme to use, for each request. The motivation for building the theme engine this way was to enable developers to switch themes based on arbitrary criteria, such as user preferences or the user agent (if you want to serve a mobile theme for phones for example). The choice is made between the active themes, which is why there is a difference between the default theme and the active themes. In order to have a say in the choice of the theme, all you have to do is implement IThemeSelector. That interface is quite simple as it only has one method, GetTheme, that takes the current RequestContext and returns a ThemeSelectorResult or null if the implementation of the interface does not want to participate in the current request (we'll see an example in a moment). ThemeSelectorResult itself is just a ThemeName string property and an integer Priority. We're using a priority so that an arbitrary number of implementations of IThemeSelector can contribute to the choice of a theme. If you look for existing implementations of the interface in Orchard, you'll find four: AdminThemeSelector: selects the TheAdmin theme with a very high priority (100) if the current request is for a page that is part of the admin. Otherwise, null is returned, which enables other implementations to choose the theme. PreviewThemeSelector: selects the preview theme if there is one, with a high priority (90), and null otherwise. This enables administrators to view the site under a different theme while everybody else continues to see the current default theme. SiteThemeSelector: this is the implementation that is doing what you expect most of the time, which is to get the current theme from site settings and set it with a priority of –5. SafeModeThemeSelector: this is the fallback implementation, which should almost never win. It sets the theme as the safe mode theme, which has no style and just uses the default templates for everything. The priority is very low (-100). While this extensibility mechanism is great to have, I wanted to bring that level of choice into the hands of the site administrator rather than just developers. In order to achieve that, I built the Vandelay Theme Picker module. The module provides administration UI to create rules for theme selection. It provides its own extensibility point (the IThemeSelectionRule interface) and one implementation of a rule: UserAgentThemeSelectorRule. This rule gets the current user agent from the context and tries to match it with a regular expression that the administrator can configure in the admin UI. You can for example configure a rule with a regular expression that matches IE6 and serve a different subtheme where the stylesheet has been tweaked for such an antique browser. Another possible configuration is to detect mobile devices from their agent string and serve the mobile theme. All those operations can be done with this module entirely from the admin UI, without writing a line of code. The module also offers the administrator the opportunity to inject a link into the front-end in a specific zone and with a specific position that enables the user to switch to the default theme if he wishes to. This is especially useful for sites that use a mobile theme but still want to allow users to use the full desktop site. While the module is nice and flexible, it may be overkill. On my own personal blog, I have only two active themes: the desktop theme and the mobile theme. I'm fine with going into code to change the criteria on which to switch the theme, so I'm not using my own Theme Picker module. Instead, I made the mobile theme a theme with code (in other words there is a csproj file in the theme). The project includes a single C# file, my MobileThemeSelector for which the code is the following: public class MobileThemeSelector : IThemeSelector { private static readonly Regex _Msie678 = new Regex(@"^Mozilla\/4\.0 \(compatible; MSIE [678]" + @"\.0; Windows NT \d\.\d(.*)\)$", RegexOptions.IgnoreCase); private ThemeSelectorResult _requestCache; private bool _requestCached; public ThemeSelectorResult GetTheme(RequestContext context) { if (_requestCached) return _requestCache; _requestCached = true; var userAgent = context.HttpContext.Request.UserAgent; if (userAgent.IndexOf("phone", StringComparison.OrdinalIgnoreCase) != -1 || _Msie678.IsMatch(userAgent) || userAgent.IndexOf("windows live writer", StringComparison.OrdinalIgnoreCase) != -1) { _requestCache = new ThemeSelectorResult { Priority = 10, ThemeName = "VuLuMobile" }; } return _requestCache; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The theme selector selects the current theme for Internet Explorer versions 6 to 8, for phones, and for Windows Live Writer (so that the theme that is used when I write posts is as simple as possible). What's interesting here is that it's the theme that selects itself here, based on its own criteria. This should give you a good panorama of what's possible in terms of dynamic theme selection in Orchard. I hope you find some fun uses for it. As usual, I can't wait to see what you're going to come up with…

  Read the article

• Telerik Releases a new Visual Entity Designer

  Love LINQ to SQL but are concerned that it is a second class citizen? Need to connect to more databases other than SQL Server? Think that the Entity Framework is too complex? Want a domain model designer for data access that is easy, yet powerful? Then the Telerik Visual Entity Designer is for you. Built on top of Telerik OpenAccess ORM, a very mature and robust product, Teleriks Visual Entity Designer is a new way to build your domain model that is very powerful and also real easy to use. How easy? Ill show you here. First Look: Using the Telerik Visual Entity Designer To get started, you need to install the Telerik OpenAccess ORM Q1 release for Visual Studio 2008 or 2010. You dont need to use any of the Telerik OpenAccess wizards, designers, or using statements. Just right click on your project and select Add|New Item from the context menu. Choose Telerik OpenAccess Domain Model from the Visual Studio project templates. (Note to existing OpenAccess users, dont run the Enable ORM wizard or any other OpenAccess menu unless you are building OpenAccess Entities.) You will then have to specify the database backend (SQL Server, SQL Azure, Oracle, MySQL, etc) and connection. After you establish your connection, select the database objects you want to add to your domain model. You can also name your model, by default it will be NameofyourdatabaseEntityDiagrams. You can click finish here if you are comfortable, or tweak some advanced settings. Many users of domain models like to add prefixes and suffixes to classes, fields, and properties as well as handle pluralization. I personally accept the defaults, however, I hate how DBAs force underscores on me, so I click on the option to remove them. You can also tweak your namespace, mapping options, and define your own code generation template to gain further control over the outputted code. This is a very powerful feature, but for now, I will just accept the defaults.   When we click finish, you can see your domain model as a file with the .rlinq extension in the Solution Explorer. You can also bring up the visual designer to view or further tweak your model by double clicking on the model in the Solution Explorer.  Time to use the model! Writing a LINQ Query Programming against the domain model is very simple using LINQ. Just set a reference to the model (line 12 of the code below) and write a standard LINQ statement (lines 14-16).  (OpenAccess users: notice the you dont need any using statements for OpenAccess or an IObjectScope, just raw LINQ against your model.) 1: using System; 2: using System.Linq; 3: //no need for anOpenAccess using statement 4:   5: namespace ConsoleApplication3 6: { 7: class Program 8: { 9: static void Main(string[] args) 10: { 11: //a reference tothe data context 12: NorthwindEntityDiagrams dat = new NorthwindEntityDiagrams(); 13: //LINQ Statement 14: var result = from c in dat.Customers 15: where c.Country == "Germany" 16: select c; 17:   18: //Print out the company name 19: foreach (var cust in result) 20: { 21: Console.WriteLine("CompanyName: " + cust.CompanyName); 22: } 23: //keep the consolewindow open 24: Console.Read(); 25: } 26: } 27: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Lines 19-24 loop through the result of our LINQ query and displays the results. Thats it! All of the super powerful features of OpenAccess are available to you to further enhance your experience, however, in most cases this is all you need. In future posts I will show how to use the Visual Designer with some other scenarios. Stay tuned. Enjoy! Technorati Tags: Telerik,OpenAccess,LINQ Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Nodemanager Init.d Script

  - by john.graves(at)oracle.com

  I’ve seen many of these floating around.  This is my favourite on an Ubuntu based machine. Just throw it into the /etc/init.d directory and update the following lines: export MW_HOME=/opt/app/wls10.3.4 user='weblogic' Then run: update-rc.d nodemanager default Everything else should be ok for 10.3.4. #!/bin/sh # ### BEGIN INIT INFO # Provides: nodemanager # Required-Start: # Required-Stop: # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: WebLogic Nodemanager ### END INIT INFO # nodemgr Oracle Weblogic NodeManager service # # chkconfig: 345 85 15 # description: Oracle Weblogic NodeManager service # ### BEGIN INIT INFO # Provides: nodemgr # Required-Start: $network $local_fs # Required-Stop: # Should-Start: # Should-Stop: # Default-Start: 3 4 5 # Default-Stop: 0 1 2 6 # Short-Description: Oracle Weblogic NodeManager service. # Description: Starts and stops Oracle Weblogic NodeManager. ### END INIT INFO # Source function library. . /lib/lsb/init-functions # set Weblogic environment defining CLASSPATH and LD_LIBRARY_PATH # to start/stop various components. export MW_HOME=/opt/app/wls10.3.4 # # Note: # The setWLSEnv.sh not only does a good job of setting the environment, # but also advertises the fact explicitly in the console! Silence it. # . $MW_HOME/wlserver_10.3/server/bin/setWLSEnv.sh > /dev/null # set NodeManager environment export NodeManagerHome=$WL_HOME/common/nodemanager NodeManagerLockFile=$NodeManagerHome/nodemanager.log.lck # check JAVA_HOME if [ -z ${JAVA_HOME:-} ]; then export JAVA_HOME=/opt/sun/products/java/jdk1.6.0_18 fi exec=$MW_HOME/wlserver_10.3/server/bin/startNodeManager.sh prog='nodemanager' user='weblogic' is_nodemgr_running() { local nodemgr_cnt=`ps -ef | \ grep -i 'java ' | \ grep -i ' weblogic.NodeManager ' | \ grep -v grep | \ wc -l` echo $nodemgr_cnt } get_nodemgr_pid() { nodemgr_pid=0 if [ `is_nodemgr_running` -eq 1 ]; then nodemgr_pid=`ps -ef | \ grep -i 'java ' | \ grep -i ' weblogic.NodeManager ' | \ grep -v grep | \ tr -s ' ' | \ cut -d' ' -f2` fi echo $nodemgr_pid } check_nodemgr_status () { local retval=0 local nodemgr_cnt=`is_nodemgr_running` if [ $nodemgr_cnt -eq 0 ]; then if [ -f $NodeManagerLockFile ]; then retval=2 else retval=3 fi elif [ $nodemgr_cnt -gt 1 ]; then retval=4 else retval=0 fi echo $retval } start() { ulimit -n 65535 [ -x $exec ] || exit 5 echo -n $"Starting $prog: " su $user -c "$exec &" retval=$? echo return $retval } stop() { echo -n $"Stopping $prog: " kill -s 9 `get_nodemgr_pid` &> /dev/null retval=$? echo [ $retval -eq 0 ] && rm -f $NodeManagerLockFile return $retval } restart() { stop start } reload() { restart } force_reload() { restart } rh_status() { local retval=`check_nodemgr_status` if [ $retval -eq 0 ]; then echo "$prog (pid:`get_nodemgr_pid`) is running..." elif [ $retval -eq 4 ]; then echo "Multiple instances of $prog are running..." else echo "$prog is stopped" fi return $retval } rh_status_q() { rh_status >/dev/null 2>&1 } case "$1" in start) rh_status_q && exit 0 $1 ;; stop) rh_status_q || exit 0 $1 ;; restart) $1 ;; reload) rh_status_q || exit 7 $1 ;; force-reload) force_reload ;; status) rh_status ;; condrestart|try-restart) rh_status_q || exit 0 restart ;; *) echo -n "Usage: $0 {" echo -n "start|" echo -n "stop|" echo -n "status|" echo -n "restart|" echo -n "condrestart|" echo -n "try-restart|" echo -n "reload|" echo -n "force-reload" echo "}" exit 2 esac exit $? .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

  Read the article

• Namespaces are obsolete

  - by Bertrand Le Roy

  To those of us who have been around for a while, namespaces have been part of the landscape. One could even say that they have been defining the large-scale features of the landscape in question. However, something happened fairly recently that I think makes this venerable structure obsolete. Before I explain this development and why it’s a superior concept to namespaces, let me recapitulate what namespaces are and why they’ve been so good to us over the years… Namespaces are used for a few different things: Scope: a namespace delimits the portion of code where a name (for a class, sub-namespace, etc.) has the specified meaning. Namespaces are usually the highest-level scoping structures in a software package. Collision prevention: name collisions are a universal problem. Some systems, such as jQuery, wave it away, but the problem remains. Namespaces provide a reasonable approach to global uniqueness (and in some implementations such as XML, enforce it). In .NET, there are ways to relocate a namespace to avoid those rare collision cases. Hierarchy: programmers like neat little boxes, and especially boxes within boxes within boxes. For some reason. Regular human beings on the other hand, tend to think linearly, which is why the Windows explorer for example has tried in a few different ways to flatten the file system hierarchy for the user. 1 is clearly useful because we need to protect our code from bleeding effects from the rest of the application (and vice versa). A language with only global constructs may be what some of us started programming on, but it’s not desirable in any way today. 2 may not be always reasonably worth the trouble (jQuery is doing fine with its global plug-in namespace), but we still need it in many cases. One should note however that globally unique names are not the only possible implementation. In fact, they are a rather extreme solution. What we really care about is collision prevention within our application. What happens outside is irrelevant. 3 is, more than anything, an aesthetical choice. A common convention has been to encode the whole pedigree of the code into the namespace. Come to think about it, we never think we need to import “Microsoft.SqlServer.Management.Smo.Agent” and that would be very hard to remember. What we want to do is bring nHibernate into our app. And this is precisely what you’ll do with modern package managers and module loaders. I want to take the specific example of RequireJS, which is commonly used with Node. Here is how you import a module with RequireJS: var http = require("http"); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is of course importing a HTTP stack module into the code. There is no noise here. Let’s break this down. Scope (1) is provided by the one scoping mechanism in JavaScript: the closure surrounding the module’s code. Whatever scoping mechanism is provided by the language would be fine here. Collision prevention (2) is very elegantly handled. Whereas relocating is an afterthought, and an exceptional measure with namespaces, it is here on the frontline. You always relocate, using an extremely familiar pattern: variable assignment. We are very much used to managing our local variable names and any possible collision will get solved very easily by picking a different name. Wait a minute, I hear some of you say. This is only taking care of collisions on the client-side, on the left of that assignment. What if I have two libraries with the name “http”? Well, You can better qualify the path to the module, which is what the require parameter really is. As for hierarchical organization, you don’t really want that, do you? RequireJS’ module pattern does elegantly cover the bases that namespaces used to cover, but it also promotes additional good practices. First, it promotes usage of self-contained, single responsibility units of code through the closure-based, stricter scoping mechanism. Namespaces are somewhat more porous, as using/import statements can be used bi-directionally, which leads us to my second point… Sane dependency graphs are easier to achieve and sustain with such a structure. With namespaces, it is easy to construct dependency cycles (that’s bad, mmkay?). With this pattern, the equivalent would be to build mega-components, which are an easier problem to spot than a decay into inter-dependent namespaces, for which you need specialized tools. I really like this pattern very much, and I would like to see more environments implement it. One could argue that dependency injection has some commonalities with this for example. What do you think? This is the half-baked result of some morning shower reflections, and I’d love to read your thoughts about it. What am I missing?

  Read the article

• Orchard shapeshifting

  - by Bertrand Le Roy

  I've shown in a previous post how to make it easier to change the layout template for specific contents or areas. But what if you want to change another shape template for specific pages, for example the main Content shape on the home page? Here's how. When we changed the layout, we had the problem that layout is created very early, so early that in fact it can't know what content is going to be rendered. For that reason, we had to rely on a filter and on the routing information to determine what layout template alternates to add. This time around, we are dealing with a content shape, a shape that is directly related to a content item. That makes things a little easier as we have access to a lot more information. What I'm going to do here is handle an event that is triggered every time a shape named "Content" is about to be displayed: public class ContentShapeProvider : IShapeTableProvider { public void Discover(ShapeTableBuilder builder) { builder.Describe("Content") .OnDisplaying(displaying => { // do stuff to the shape }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This handler is implemented in a shape table provider which is where you do all shape related site-wide operations. The first thing we want to do in this event handler is check that we are on the front-end, displaying the "Detail" version, and not the "Summary" or the admin editor: if (displaying.ShapeMetadata.DisplayType == "Detail") { Now I want to provide the ability for the theme developer to provide an alternative template named "Content-HomePage.cshtml" for the home page. In order to determine if we are indeed on the home page I can look at the current site's home page property, which for the default home page provider contains the home page item's id at the end after a semicolon. Compare that with the content item id for the shape we are looking at and you can know if that's the homepage content item. Please note that if that content is also displayed on another page than the home page it will also get the alternate: we are altering at the shape level and not at the URL/routing level like we did with the layout. ContentItem contentItem = displaying.Shape.ContentItem; if (_workContextAccessor.GetContext().CurrentSite .HomePage.EndsWith(';' + contentItem.Id.ToString())) { _workContextAccessor is an injected instance of IWorkContextAccessor from which we can get the current site and its home page. Finally, once we've determined that we are in the specific conditions that we want to alter, we can add the alternate: displaying.ShapeMetadata.Alternates.Add("Content__HomePage"); And that's it really. Here's the full code for the shape provider that I added to a custom theme (but it could really live in any module or theme): using Orchard; using Orchard.ContentManagement; using Orchard.DisplayManagement.Descriptors; namespace CustomLayoutMachine.ShapeProviders { public class ContentShapeProvider : IShapeTableProvider { private readonly IWorkContextAccessor _workContextAccessor; public ContentShapeProvider( IWorkContextAccessor workContextAccessor) { _workContextAccessor = workContextAccessor; } public void Discover(ShapeTableBuilder builder) { builder.Describe("Content") .OnDisplaying(displaying => { if (displaying.ShapeMetadata.DisplayType == "Detail") { ContentItem contentItem = displaying.Shape.ContentItem; if (_workContextAccessor.GetContext() .CurrentSite.HomePage.EndsWith( ';' + contentItem.Id.ToString())) { displaying.ShapeMetadata.Alternates.Add( "Content__HomePage"); } } }); } } } The code for the custom theme, with layout and content alternates, can be downloaded from the following link: Orchard.Themes.CustomLayoutMachine.1.0.nupkg Note: this code is going to be used in the Contoso theme that should be available soon from the theme gallery.

  Read the article

• Storing non-content data in Orchard

  - by Bertrand Le Roy

  A CMS like Orchard is, by definition, designed to store content. What differentiates content from other kinds of data is rather subtle. The way I would describe it is by saying that if you would put each instance of a kind of data on its own web page, if it would make sense to add comments to it, or tags, or ratings, then it is content and you can store it in Orchard using all the convenient composition options that it offers. Otherwise, it probably isn't and you can store it using somewhat simpler means that I will now describe. In one of the modules I wrote, Vandelay.ThemePicker, there is some configuration data for the module. That data is not content by the definition I gave above. Let's look at how this data is stored and queried. The configuration data in question is a set of records, each of which has a number of properties: public class SettingsRecord { public virtual int Id { get; set;} public virtual string RuleType { get; set; } public virtual string Name { get; set; } public virtual string Criterion { get; set; } public virtual string Theme { get; set; } public virtual int Priority { get; set; } public virtual string Zone { get; set; } public virtual string Position { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Each property has to be virtual for nHibernate to handle it (it creates derived classed that are instrumented in all kinds of ways). We also have an Id property. The way these records will be stored in the database is described from a migration: public int Create() { SchemaBuilder.CreateTable("SettingsRecord", table => table .Column<int>("Id", column => column.PrimaryKey().Identity()) .Column<string>("RuleType", column => column.NotNull().WithDefault("")) .Column<string>("Name", column => column.NotNull().WithDefault("")) .Column<string>("Criterion", column => column.NotNull().WithDefault("")) .Column<string>("Theme", column => column.NotNull().WithDefault("")) .Column<int>("Priority", column => column.NotNull().WithDefault(10)) .Column<string>("Zone", column => column.NotNull().WithDefault("")) .Column<string>("Position", column => column.NotNull().WithDefault("")) ); return 1; } When we enable the feature, the migration will run, which will create the table in the database. Once we've done that, all we have to do in order to use the data is inject an IRepository<SettingsRecord>, which is what I'm doing from the set of helpers I put under the SettingsService class: private readonly IRepository<SettingsRecord> _repository; private readonly ISignals _signals; private readonly ICacheManager _cacheManager; public SettingsService( IRepository<SettingsRecord> repository, ISignals signals, ICacheManager cacheManager) { _repository = repository; _signals = signals; _cacheManager = cacheManager; } The repository has a Table property, which implements IQueryable<SettingsRecord> (enabling all kind of Linq queries) as well as methods such as Delete and Create. Here's for example how I'm getting all the records in the table: _repository.Table.ToList() And here's how I'm deleting a record: _repository.Delete(_repository.Get(r => r.Id == id)); And here's how I'm creating one: _repository.Create(new SettingsRecord { Name = name, RuleType = ruleType, Criterion = criterion, Theme = theme, Priority = priority, Zone = zone, Position = position }); In summary, you create a record class, a migration, and you're in business and can just manipulate the data through the repository that the framework is exposing. You even get ambient transactions from the work context.

  Read the article

• AutoIt scripts runs without error but I can't see archive?

  - by Scott

  #include <File.au3> #include <Zip.au3> ; bad file extensions Local $extData="ade|adp|app|asa|ashx|asp|bas|bat|cdx|cer|chm|class|cmd|com|cpl|crt|csh|der|exe|fxp|gadget|hlp|hta|htr|htw|ida|idc|idq|ins|isp|its|jse|ksh|lnk|mad|maf|mag|mam|maq|mar|mas|mat|mau|mav|maw|mda|mdb|mde|mdt|mdw|mdz|msc|msh|msh1|msh1xml|msh2|msh2xml|mshxml|msi|msp|mst|ops|pcd|pif|prf|prg|printer|pst|reg|rem|scf|scr|sct|shb|shs|shtm|shtml|soap|stm|url|vb|vbe|vbs|ws|wsc|wsf|wsh" Local $extensions = StringSplit($extData, "|") ; What is the root directory? $rootDirectory = InputBox("Root Directory", "Please enter the root directory...") archiveDir($rootDirectory) Func archiveDir($dir) $goDirs = True $goFiles = True ; Get all the files under the current dir $allOfDir = _FileListToArray($dir) Local $countDirs = 0 Local $countFiles = 0 $imax = UBound($allOfDir) For $i = 0 to $imax - 1 If StringInStr(FileGetAttrib($dir & "\" & $allOfDir[$i]),"D") Then $countDirs = $countDirs + 1 ElseIf StringInStr(($allOfDir[$i]),".") Then $countFiles = $countFiles + 1 EndIf Next MsgBox(0, "Value of $countDirs in " & $dir, $countDirs) MsgBox(0, "Value of $countFiles in " & $dir, $countFiles) If ($countDirs > 0) Then Local $allDirs[$countDirs] $goDirs = True Else $goDirs = False EndIf If ($countFiles > 0) Then Local $allFiles[$countFiles] $goFiles = True Else $goFiles = False EndIf $dirCount = 0 $fileCount = 0 For $i = 0 to $imax - 1 If (StringInStr(FileGetAttrib($dir & "\" & $allOfDir[$i]),"D")) And ($goDirs == True) Then $allDirs[$dirCount] = $allOfDir[$i] $dirCount = $dirCount + 1 ElseIf (StringInStr(($allOfDir[$i]),".")) And ($goFiles == True) Then $allFiles[$fileCount] = $allOfDir[$i] $fileCount = $fileCount + 1 EndIf Next ; Zip them if need be in current spot using 'ext_zip.zip' as file name, loop through each file ext. If ($goFiles == True) Then $emax = UBound($extensions) $fmax = UBound($allFiles) For $e = 0 to $emax - 1 For $f = 0 to $fmax - 1 $currentExt = getExt($allFiles[$f]) If ($currentExt == $extensions[$e]) Then $zip = _Zip_Create($dir & "\" & $currentExt & "_zip.zip") _Zip_AddFile($zip, $allFiles[$f]) EndIf Next Next EndIf ; Get all dirs under current DirCopy ; For each dir, recursive call from step 2 If ($goDirs == True) Then $dmax = UBound($allDirs) $rootDirectory = $rootDirectory & "\" For $d = 0 to $dmax - 1 archiveDir($rootDirectory & $allDirs[$d]) Next EndIf EndFunc Func getExt($filename) $pos = StringInStr($filename, ".") $retval = StringTrimLeft($filename, $pos + 1) Return $retval EndFunc This should output the .zip archives in the directories it finds the files that it needs to zip but it doesn't. Is there something I have to do after I create and add files to the archive within the code to put this created archive in the directory?

  Read the article

• Help to Install STLPort in VC6

  - by Yan Cheng CHEOK

  I try to follow the following steps to install STLPort in VC6 1) I change C:\Program Files\Microsoft Visual Studio\VC98\Bin\VCVARS32.BAT content set INCLUDE=%MSVCDir%\ATL\INCLUDE;%MSVCDir%\INCLUDE;%MSVCDir%\MFC\INCLUDE;%INCLUDE% set LIB=%MSVCDir%\LIB;%MSVCDir%\MFC\LIB;%LIB% to (The directory C:\STLport-5.2.1\lib is not exsits?) set INCLUDE=C:\STLport-5.2.1\stlport;%MSVCDir%\ATL\INCLUDE;%MSVCDir%\INCLUDE;%MSVCDir%\MFC\INCLUDE;%INCLUDE% set LIB=C:\STLport-5.2.1\lib;%MSVCDir%\LIB;%MSVCDir%\MFC\LIB;%LIB% 2) I C:\>cd C:\STLport-5.2.1\build\lib C:\STLport-5.2.1\build\lib>"c:\Program Files\Microsoft Visual Studio\VC98\bin\VCVARS32.BAT" Setting environment for using Microsoft Visual C++ tools. C:\STLport-5.2.1\build\lib>c:\STLport-5.2.1\configure.bat msvc6 STLport Configuration Tool for Windows The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. Setting compiler: Microsoft Visual C++ 6.0 The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. The system cannot find the path specified. Setting platform: Windows XP The system cannot find the path specified. Done configuring STLport. Go to build/lib folder and type "nmake clean install" to build and install STLport to the "lib" and "bin" folders. Go to build/test/unit folder and type nmake clean install to build unit tests and install them in bin folder. 3) The code within configure.bat, which give me The system cannot find the path specified is REM initially create/overwrite config.mak echo # STLport Configuration Tool for Windows > build\Makefiles\nmake\config.mak echo # >> build\Makefiles\nmake\config.mak echo # config.mak generated with command line: >> build\Makefiles\nmake\config.mak echo # configure %1 %2 %3 %4 %5 %6 %7 %8 %9 >> build\Makefiles\nmake\config.mak echo # >> build\Makefiles\nmake\config.mak What I shall change them to? How can I continue the build? Thanks.

  Read the article

• AutoIt scripts runs without error but I can't see archive? - UPDATE

  - by Scott

  #include <File.au3> #include <Zip.au3> #include <Array.au3> ; bad file extensions Local $extData="ade|adp|app|asa|ashx|asp|bas|bat|cdx|cer|chm|class|cmd|com|cpl|crt|csh|der|exe|fxp|gadget|hlp|hta|htr|htw|ida|idc|idq|ins|isp|its|jse|ksh|lnk|mad|maf|mag|mam|maq|mar|mas|mat|mau|mav|maw|mda|mdb|mde|mdt|mdw|mdz|msc|msh|msh1|msh1xml|msh2|msh2xml|mshxml|msi|msp|mst|ops|pcd|pif|prf|prg|printer|pst|reg|rem|scf|scr|sct|shb|shs|shtm|shtml|soap|stm|url|vb|vbe|vbs|ws|wsc|wsf|wsh" Local $extensions = StringSplit($extData, "|") ; What is the root directory? $rootDirectory = InputBox("Root Directory", "Please enter the root directory...") archiveDir($rootDirectory) Func archiveDir($dir) $goDirs = True $goFiles = True ; Get all the files under the current dir $allOfDir = _FileListToArray($dir) $tmax = UBound($allOfDir) For $t = 0 to $tmax - 1 Next Local $countDirs = 0 Local $countFiles = 0 $imax = UBound($allOfDir) For $i = 0 to $imax - 1 If StringInStr(FileGetAttrib($dir & "\" & $allOfDir[$i]),"D") Then $countDirs = $countDirs + 1 ElseIf StringInStr(($allOfDir[$i]),".") Then $countFiles = $countFiles + 1 EndIf Next If ($countDirs > 0) Then Local $allDirs[$countDirs] $goDirs = True Else $goDirs = False EndIf If ($countFiles > 0) Then Local $allFiles[$countFiles] $goFiles = True Else $goFiles = False EndIf $dirCount = 0 $fileCount = 0 For $i = 0 to $imax - 1 If (StringInStr(FileGetAttrib($dir & "\" & $allOfDir[$i]),"D")) And ($goDirs == True) Then $allDirs[$dirCount] = $allOfDir[$i] $dirCount = $dirCount + 1 ElseIf (StringInStr(($allOfDir[$i]),".")) And ($goFiles == True) Then $allFiles[$fileCount] = $allOfDir[$i] $fileCount = $fileCount + 1 EndIf Next ; Zip them if need be in current spot using 'ext_zip.zip' as file name, loop through each file ext. If ($goFiles == True) Then $fmax = UBound($allFiles) For $f = 0 to $fmax - 1 $currentExt = getExt($allFiles[$f]) $position = _ArraySearch($extensions, $currentExt) If @error Then MsgBox(0, "Not Found", "Not Found") Else $zip = _Zip_Create($dir & "\" & $currentExt & "_zip.zip") _Zip_AddFile($zip, $dir & "\" & $allFiles[$f]) EndIf Next EndIf ; Get all dirs under current DirCopy ; For each dir, recursive call from step 2 If ($goDirs == True) Then $dmax = UBound($allDirs) $rootDirectory = $rootDirectory & "\" For $d = 0 to $dmax - 1 archiveDir($rootDirectory & $allDirs[$d]) Next EndIf EndFunc Func getExt($filename) $pos = StringInStr($filename, ".") $retval = StringTrimLeft($filename, $pos - 1) Return $retval EndFunc Updated, fixed a lot of bugs. Still not working. Like I said I have a list of 'bad' file extensions, this script should go through a directory of files (and subdirectories), and zip up (in separate zip files for each bad extension), all files WITH those bad extensions in the directories it finds them. What is wrong???

  Read the article

• Parallelism in .NET – Part 14, The Different Forms of Task

  - by Reed

  Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

  Read the article

• Parallelism in .NET – Part 15, Making Tasks Run: The TaskScheduler

  - by Reed

  In my introduction to the Task class, I specifically made mention that the Task class does not directly provide it’s own execution.  In addition, I made a strong point that the Task class itself is not directly related to threads or multithreading.  Rather, the Task class is used to implement our decomposition of tasks.  Once we’ve implemented our tasks, we need to execute them.  In the Task Parallel Library, the execution of Tasks is handled via an instance of the TaskScheduler class. The TaskScheduler class is an abstract class which provides a single function: it schedules the tasks and executes them within an appropriate context.  This class is the class which actually runs individual Task instances.  The .NET Framework provides two (internal) implementations of the TaskScheduler class. Since a Task, based on our decomposition, should be a self-contained piece of code, parallel execution makes sense when executing tasks.  The default implementation of the TaskScheduler class, and the one most often used, is based on the ThreadPool.  This can be retrieved via the TaskScheduler.Default property, and is, by default, what is used when we just start a Task instance with Task.Start(). Normally, when a Task is started by the default TaskScheduler, the task will be treated as a single work item, and run on a ThreadPool thread.  This pools tasks, and provides Task instances all of the advantages of the ThreadPool, including thread pooling for reduced resource usage, and an upper cap on the number of work items.  In addition, .NET 4 brings us a much improved thread pool, providing work stealing and reduced locking within the thread pool queues.  By using the default TaskScheduler, our Tasks are run asynchronously on the ThreadPool. There is one notable exception to my above statements when using the default TaskScheduler.  If a Task is created with the TaskCreationOptions set to TaskCreationOptions.LongRunning, the default TaskScheduler will generate a new thread for that Task, at least in the current implementation.  This is useful for Tasks which will persist for most of the lifetime of your application, since it prevents your Task from starving the ThreadPool of one of it’s work threads. The Task Parallel Library provides one other implementation of the TaskScheduler class.  In addition to providing a way to schedule tasks on the ThreadPool, the framework allows you to create a TaskScheduler which works within a specified SynchronizationContext.  This scheduler can be retrieved within a thread that provides a valid SynchronizationContext by calling the TaskScheduler.FromCurrentSynchronizationContext() method. This implementation of TaskScheduler is intended for use with user interface development.  Windows Forms and Windows Presentation Foundation both require any access to user interface controls to occur on the same thread that created the control.  For example, if you want to set the text within a Windows Forms TextBox, and you’re working on a background thread, that UI call must be marshaled back onto the UI thread.  The most common way this is handled depends on the framework being used.  In Windows Forms, Control.Invoke or Control.BeginInvoke is most often used.  In WPF, the equivelent calls are Dispatcher.Invoke or Dispatcher.BeginInvoke. As an example, say we’re working on a background thread, and we want to update a TextBlock in our user interface with a status label.  The code would typically look something like: // Within background thread work... string status = GetUpdatedStatus(); Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action( () => { statusLabel.Text = status; })); // Continue on in background method .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This works fine, but forces your method to take a dependency on WPF or Windows Forms.  There is an alternative option, however.  Both Windows Forms and WPF, when initialized, setup a SynchronizationContext in their thread, which is available on the UI thread via the SynchronizationContext.Current property.  This context is used by classes such as BackgroundWorker to marshal calls back onto the UI thread in a framework-agnostic manner. The Task Parallel Library provides the same functionality via the TaskScheduler.FromCurrentSynchronizationContext() method.  When setting up our Tasks, as long as we’re working on the UI thread, we can construct a TaskScheduler via: TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); We then can use this scheduler on any thread to marshal data back onto the UI thread.  For example, our code above can then be rewritten as: string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); // Continue on in background method This is nice since it allows us to write code that isn’t tied to Windows Forms or WPF, but is still fully functional with those technologies.  I’ll discuss even more uses for the SynchronizationContext based TaskScheduler when I demonstrate task continuations, but even without continuations, this is a very useful construct. In addition to the two implementations provided by the Task Parallel Library, it is possible to implement your own TaskScheduler.  The ParallelExtensionsExtras project within the Samples for Parallel Programming provides nine sample TaskScheduler implementations.  These include schedulers which restrict the maximum number of concurrent tasks, run tasks on a single threaded apartment thread, use a new thread per task, and more.

  Read the article

< Previous Page | 6 7 8 9 10 11  | Next Page >