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7FileOutputFormat (Hadoop 0.20.1 API)
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91org.apache.hadoop.mapred</FONT>
92<BR>
93Class FileOutputFormat&lt;K,V&gt;</H2>
94<PRE>
95<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">java.lang.Object</A>
96  <IMG SRC="../../../../resources/inherit.gif" ALT="extended by "><B>org.apache.hadoop.mapred.FileOutputFormat&lt;K,V&gt;</B>
97</PRE>
98<DL>
99<DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html" title="interface in org.apache.hadoop.mapred">OutputFormat</A>&lt;K,V&gt;</DD>
100</DL>
101<DL>
102<DT><B>Direct Known Subclasses:</B> <DD><A HREF="../../../../org/apache/hadoop/contrib/index/mapred/IndexUpdateOutputFormat.html" title="class in org.apache.hadoop.contrib.index.mapred">IndexUpdateOutputFormat</A>, <A HREF="../../../../org/apache/hadoop/mapred/MapFileOutputFormat.html" title="class in org.apache.hadoop.mapred">MapFileOutputFormat</A>, <A HREF="../../../../org/apache/hadoop/mapred/lib/MultipleOutputFormat.html" title="class in org.apache.hadoop.mapred.lib">MultipleOutputFormat</A>, <A HREF="../../../../org/apache/hadoop/mapred/SequenceFileOutputFormat.html" title="class in org.apache.hadoop.mapred">SequenceFileOutputFormat</A>, <A HREF="../../../../org/apache/hadoop/mapred/TextOutputFormat.html" title="class in org.apache.hadoop.mapred">TextOutputFormat</A></DD>
103</DL>
104<HR>
105<DL>
106<DT><PRE>public abstract class <B>FileOutputFormat&lt;K,V&gt;</B><DT>extends <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A><DT>implements <A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html" title="interface in org.apache.hadoop.mapred">OutputFormat</A>&lt;K,V&gt;</DL>
107</PRE>
108
109<P>
110A base class for <A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html" title="interface in org.apache.hadoop.mapred"><CODE>OutputFormat</CODE></A>.
111<P>
112
113<P>
114<HR>
115
116<P>
117
118<!-- ======== CONSTRUCTOR SUMMARY ======== -->
119
120<A NAME="constructor_summary"><!-- --></A>
121<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
122<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
123<TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2">
124<B>Constructor Summary</B></FONT></TH>
125</TR>
126<TR BGCOLOR="white" CLASS="TableRowColor">
127<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#FileOutputFormat()">FileOutputFormat</A></B>()</CODE>
128
129<BR>
130&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</TD>
131</TR>
132</TABLE>
133&nbsp;
134<!-- ========== METHOD SUMMARY =========== -->
135
136<A NAME="method_summary"><!-- --></A>
137<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
138<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
139<TH ALIGN="left" COLSPAN="2"><FONT SIZE="+2">
140<B>Method Summary</B></FONT></TH>
141</TR>
142<TR BGCOLOR="white" CLASS="TableRowColor">
143<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
144<CODE>&nbsp;void</CODE></FONT></TD>
145<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#checkOutputSpecs(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf)">checkOutputSpecs</A></B>(<A HREF="../../../../org/apache/hadoop/fs/FileSystem.html" title="class in org.apache.hadoop.fs">FileSystem</A>&nbsp;ignored,
146                 <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;job)</CODE>
147
148<BR>
149&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Check for validity of the output-specification for the job.</TD>
150</TR>
151<TR BGCOLOR="white" CLASS="TableRowColor">
152<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
153<CODE>static&nbsp;boolean</CODE></FONT></TD>
154<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getCompressOutput(org.apache.hadoop.mapred.JobConf)">getCompressOutput</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</CODE>
155
156<BR>
157&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Is the job output compressed?</TD>
158</TR>
159<TR BGCOLOR="white" CLASS="TableRowColor">
160<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
161<CODE>static&nbsp;<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt;</CODE></FONT></TD>
162<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getOutputCompressorClass(org.apache.hadoop.mapred.JobConf, java.lang.Class)">getOutputCompressorClass</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
163                         <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt;&nbsp;defaultValue)</CODE>
164
165<BR>
166&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> for compressing the job outputs.</TD>
167</TR>
168<TR BGCOLOR="white" CLASS="TableRowColor">
169<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
170<CODE>static&nbsp;<A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A></CODE></FONT></TD>
171<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getOutputPath(org.apache.hadoop.mapred.JobConf)">getOutputPath</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</CODE>
172
173<BR>
174&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the output directory for the map-reduce job.</TD>
175</TR>
176<TR BGCOLOR="white" CLASS="TableRowColor">
177<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
178<CODE>static&nbsp;<A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A></CODE></FONT></TD>
179<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getPathForCustomFile(org.apache.hadoop.mapred.JobConf, java.lang.String)">getPathForCustomFile</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
180                     <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)</CODE>
181
182<BR>
183&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Helper function to generate a <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> for a file that is unique for
184 the task within the job output directory.</TD>
185</TR>
186<TR BGCOLOR="white" CLASS="TableRowColor">
187<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
188<CODE>abstract &nbsp;<A HREF="../../../../org/apache/hadoop/mapred/RecordWriter.html" title="interface in org.apache.hadoop.mapred">RecordWriter</A>&lt;<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">K</A>,<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">V</A>&gt;</CODE></FONT></TD>
189<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getRecordWriter(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf, java.lang.String, org.apache.hadoop.util.Progressable)">getRecordWriter</A></B>(<A HREF="../../../../org/apache/hadoop/fs/FileSystem.html" title="class in org.apache.hadoop.fs">FileSystem</A>&nbsp;ignored,
190                <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;job,
191                <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name,
192                <A HREF="../../../../org/apache/hadoop/util/Progressable.html" title="interface in org.apache.hadoop.util">Progressable</A>&nbsp;progress)</CODE>
193
194<BR>
195&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the <A HREF="../../../../org/apache/hadoop/mapred/RecordWriter.html" title="interface in org.apache.hadoop.mapred"><CODE>RecordWriter</CODE></A> for the given job.</TD>
196</TR>
197<TR BGCOLOR="white" CLASS="TableRowColor">
198<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
199<CODE>static&nbsp;<A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A></CODE></FONT></TD>
200<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getTaskOutputPath(org.apache.hadoop.mapred.JobConf, java.lang.String)">getTaskOutputPath</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
201                  <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)</CODE>
202
203<BR>
204&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Helper function to create the task's temporary output directory and
205 return the path to the task's output file.</TD>
206</TR>
207<TR BGCOLOR="white" CLASS="TableRowColor">
208<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
209<CODE>static&nbsp;<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A></CODE></FONT></TD>
210<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getUniqueName(org.apache.hadoop.mapred.JobConf, java.lang.String)">getUniqueName</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
211              <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)</CODE>
212
213<BR>
214&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Helper function to generate a name that is unique for the task.</TD>
215</TR>
216<TR BGCOLOR="white" CLASS="TableRowColor">
217<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
218<CODE>static&nbsp;<A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A></CODE></FONT></TD>
219<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)">getWorkOutputPath</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</CODE>
220
221<BR>
222&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Get the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the task's temporary output directory
223  for the map-reduce job
224 
225 <h4 id="SideEffectFiles">Tasks' Side-Effect Files</TD>
226</TR>
227<TR BGCOLOR="white" CLASS="TableRowColor">
228<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
229<CODE>static&nbsp;void</CODE></FONT></TD>
230<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#setCompressOutput(org.apache.hadoop.mapred.JobConf, boolean)">setCompressOutput</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
231                  boolean&nbsp;compress)</CODE>
232
233<BR>
234&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Set whether the output of the job is compressed.</TD>
235</TR>
236<TR BGCOLOR="white" CLASS="TableRowColor">
237<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
238<CODE>static&nbsp;void</CODE></FONT></TD>
239<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#setOutputCompressorClass(org.apache.hadoop.mapred.JobConf, java.lang.Class)">setOutputCompressorClass</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
240                         <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt;&nbsp;codecClass)</CODE>
241
242<BR>
243&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Set the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> to be used to compress job outputs.</TD>
244</TR>
245<TR BGCOLOR="white" CLASS="TableRowColor">
246<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
247<CODE>static&nbsp;void</CODE></FONT></TD>
248<TD><CODE><B><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#setOutputPath(org.apache.hadoop.mapred.JobConf, org.apache.hadoop.fs.Path)">setOutputPath</A></B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
249              <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A>&nbsp;outputDir)</CODE>
250
251<BR>
252&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Set the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> of the output directory for the map-reduce job.</TD>
253</TR>
254</TABLE>
255&nbsp;<A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A>
256<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
257<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
258<TH ALIGN="left"><B>Methods inherited from class java.lang.<A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</A></B></TH>
259</TR>
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262</TR>
263</TABLE>
264&nbsp;
265<P>
266
267<!-- ========= CONSTRUCTOR DETAIL ======== -->
268
269<A NAME="constructor_detail"><!-- --></A>
270<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
271<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
272<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
273<B>Constructor Detail</B></FONT></TH>
274</TR>
275</TABLE>
276
277<A NAME="FileOutputFormat()"><!-- --></A><H3>
278FileOutputFormat</H3>
279<PRE>
280public <B>FileOutputFormat</B>()</PRE>
281<DL>
282</DL>
283
284<!-- ============ METHOD DETAIL ========== -->
285
286<A NAME="method_detail"><!-- --></A>
287<TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY="">
288<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
289<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
290<B>Method Detail</B></FONT></TH>
291</TR>
292</TABLE>
293
294<A NAME="setCompressOutput(org.apache.hadoop.mapred.JobConf, boolean)"><!-- --></A><H3>
295setCompressOutput</H3>
296<PRE>
297public static void <B>setCompressOutput</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
298                                     boolean&nbsp;compress)</PRE>
299<DL>
300<DD>Set whether the output of the job is compressed.
301<P>
302<DD><DL>
303</DL>
304</DD>
305<DD><DL>
306<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred"><CODE>JobConf</CODE></A> to modify<DD><CODE>compress</CODE> - should the output of the job be compressed?</DL>
307</DD>
308</DL>
309<HR>
310
311<A NAME="getCompressOutput(org.apache.hadoop.mapred.JobConf)"><!-- --></A><H3>
312getCompressOutput</H3>
313<PRE>
314public static boolean <B>getCompressOutput</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</PRE>
315<DL>
316<DD>Is the job output compressed?
317<P>
318<DD><DL>
319</DL>
320</DD>
321<DD><DL>
322<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred"><CODE>JobConf</CODE></A> to look in
323<DT><B>Returns:</B><DD><code>true</code> if the job output should be compressed,
324         <code>false</code> otherwise</DL>
325</DD>
326</DL>
327<HR>
328
329<A NAME="setOutputCompressorClass(org.apache.hadoop.mapred.JobConf, java.lang.Class)"><!-- --></A><H3>
330setOutputCompressorClass</H3>
331<PRE>
332public static void <B>setOutputCompressorClass</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
333                                            <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt;&nbsp;codecClass)</PRE>
334<DL>
335<DD>Set the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> to be used to compress job outputs.
336<P>
337<DD><DL>
338</DL>
339</DD>
340<DD><DL>
341<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred"><CODE>JobConf</CODE></A> to modify<DD><CODE>codecClass</CODE> - the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> to be used to
342                   compress the job outputs</DL>
343</DD>
344</DL>
345<HR>
346
347<A NAME="getOutputCompressorClass(org.apache.hadoop.mapred.JobConf, java.lang.Class)"><!-- --></A><H3>
348getOutputCompressorClass</H3>
349<PRE>
350public static <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt; <B>getOutputCompressorClass</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
351                                                                         <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true" title="class or interface in java.lang">Class</A>&lt;? extends <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress">CompressionCodec</A>&gt;&nbsp;defaultValue)</PRE>
352<DL>
353<DD>Get the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> for compressing the job outputs.
354<P>
355<DD><DL>
356</DL>
357</DD>
358<DD><DL>
359<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred"><CODE>JobConf</CODE></A> to look in<DD><CODE>defaultValue</CODE> - the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> to return if not set
360<DT><B>Returns:</B><DD>the <A HREF="../../../../org/apache/hadoop/io/compress/CompressionCodec.html" title="interface in org.apache.hadoop.io.compress"><CODE>CompressionCodec</CODE></A> to be used to compress the
361         job outputs
362<DT><B>Throws:</B>
363<DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/lang/IllegalArgumentException.html?is-external=true" title="class or interface in java.lang">IllegalArgumentException</A></CODE> - if the class was specified, but not found</DL>
364</DD>
365</DL>
366<HR>
367
368<A NAME="getRecordWriter(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf, java.lang.String, org.apache.hadoop.util.Progressable)"><!-- --></A><H3>
369getRecordWriter</H3>
370<PRE>
371public abstract <A HREF="../../../../org/apache/hadoop/mapred/RecordWriter.html" title="interface in org.apache.hadoop.mapred">RecordWriter</A>&lt;<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">K</A>,<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">V</A>&gt; <B>getRecordWriter</B>(<A HREF="../../../../org/apache/hadoop/fs/FileSystem.html" title="class in org.apache.hadoop.fs">FileSystem</A>&nbsp;ignored,
372                                                  <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;job,
373                                                  <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name,
374                                                  <A HREF="../../../../org/apache/hadoop/util/Progressable.html" title="interface in org.apache.hadoop.util">Progressable</A>&nbsp;progress)
375                                           throws <A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></PRE>
376<DL>
377<DD><B>Description copied from interface: <CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html#getRecordWriter(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf, java.lang.String, org.apache.hadoop.util.Progressable)">OutputFormat</A></CODE></B></DD>
378<DD>Get the <A HREF="../../../../org/apache/hadoop/mapred/RecordWriter.html" title="interface in org.apache.hadoop.mapred"><CODE>RecordWriter</CODE></A> for the given job.
379<P>
380<DD><DL>
381<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html#getRecordWriter(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf, java.lang.String, org.apache.hadoop.util.Progressable)">getRecordWriter</A></CODE> in interface <CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html" title="interface in org.apache.hadoop.mapred">OutputFormat</A>&lt;<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">K</A>,<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">V</A>&gt;</CODE></DL>
382</DD>
383<DD><DL>
384<DD><CODE>job</CODE> - configuration for the job whose output is being written.<DD><CODE>name</CODE> - the unique name for this part of the output.<DD><CODE>progress</CODE> - mechanism for reporting progress while writing to file.
385<DT><B>Returns:</B><DD>a <A HREF="../../../../org/apache/hadoop/mapred/RecordWriter.html" title="interface in org.apache.hadoop.mapred"><CODE>RecordWriter</CODE></A> to write the output for the job.
386<DT><B>Throws:</B>
387<DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></CODE></DL>
388</DD>
389</DL>
390<HR>
391
392<A NAME="checkOutputSpecs(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf)"><!-- --></A><H3>
393checkOutputSpecs</H3>
394<PRE>
395public void <B>checkOutputSpecs</B>(<A HREF="../../../../org/apache/hadoop/fs/FileSystem.html" title="class in org.apache.hadoop.fs">FileSystem</A>&nbsp;ignored,
396                             <A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;job)
397                      throws <A HREF="../../../../org/apache/hadoop/mapred/FileAlreadyExistsException.html" title="class in org.apache.hadoop.mapred">FileAlreadyExistsException</A>,
398                             <A HREF="../../../../org/apache/hadoop/mapred/InvalidJobConfException.html" title="class in org.apache.hadoop.mapred">InvalidJobConfException</A>,
399                             <A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></PRE>
400<DL>
401<DD><B>Description copied from interface: <CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html#checkOutputSpecs(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf)">OutputFormat</A></CODE></B></DD>
402<DD>Check for validity of the output-specification for the job.
403 
404 <p>This is to validate the output specification for the job when it is
405 a job is submitted.  Typically checks that it does not already exist,
406 throwing an exception when it already exists, so that output is not
407 overwritten.</p>
408<P>
409<DD><DL>
410<DT><B>Specified by:</B><DD><CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html#checkOutputSpecs(org.apache.hadoop.fs.FileSystem, org.apache.hadoop.mapred.JobConf)">checkOutputSpecs</A></CODE> in interface <CODE><A HREF="../../../../org/apache/hadoop/mapred/OutputFormat.html" title="interface in org.apache.hadoop.mapred">OutputFormat</A>&lt;<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">K</A>,<A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html" title="type parameter in FileOutputFormat">V</A>&gt;</CODE></DL>
411</DD>
412<DD><DL>
413<DD><CODE>job</CODE> - job configuration.
414<DT><B>Throws:</B>
415<DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></CODE> - when output should not be attempted
416<DD><CODE><A HREF="../../../../org/apache/hadoop/mapred/FileAlreadyExistsException.html" title="class in org.apache.hadoop.mapred">FileAlreadyExistsException</A></CODE>
417<DD><CODE><A HREF="../../../../org/apache/hadoop/mapred/InvalidJobConfException.html" title="class in org.apache.hadoop.mapred">InvalidJobConfException</A></CODE></DL>
418</DD>
419</DL>
420<HR>
421
422<A NAME="setOutputPath(org.apache.hadoop.mapred.JobConf, org.apache.hadoop.fs.Path)"><!-- --></A><H3>
423setOutputPath</H3>
424<PRE>
425public static void <B>setOutputPath</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
426                                 <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A>&nbsp;outputDir)</PRE>
427<DL>
428<DD>Set the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> of the output directory for the map-reduce job.
429<P>
430<DD><DL>
431</DL>
432</DD>
433<DD><DL>
434<DT><B>Parameters:</B><DD><CODE>conf</CODE> - The configuration of the job.<DD><CODE>outputDir</CODE> - the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> of the output directory for
435 the map-reduce job.</DL>
436</DD>
437</DL>
438<HR>
439
440<A NAME="getOutputPath(org.apache.hadoop.mapred.JobConf)"><!-- --></A><H3>
441getOutputPath</H3>
442<PRE>
443public static <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A> <B>getOutputPath</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</PRE>
444<DL>
445<DD>Get the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the output directory for the map-reduce job.
446<P>
447<DD><DL>
448</DL>
449</DD>
450<DD><DL>
451
452<DT><B>Returns:</B><DD>the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the output directory for the map-reduce job.<DT><B>See Also:</B><DD><A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"><CODE>getWorkOutputPath(JobConf)</CODE></A></DL>
453</DD>
454</DL>
455<HR>
456
457<A NAME="getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"><!-- --></A><H3>
458getWorkOutputPath</H3>
459<PRE>
460public static <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A> <B>getWorkOutputPath</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf)</PRE>
461<DL>
462<DD>Get the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the task's temporary output directory
463  for the map-reduce job
464 
465 <h4 id="SideEffectFiles">Tasks' Side-Effect Files</h4>
466 
467 <p><i>Note:</i> The following is valid only if the <A HREF="../../../../org/apache/hadoop/mapred/OutputCommitter.html" title="class in org.apache.hadoop.mapred"><CODE>OutputCommitter</CODE></A>
468  is <A HREF="../../../../org/apache/hadoop/mapred/FileOutputCommitter.html" title="class in org.apache.hadoop.mapred"><CODE>FileOutputCommitter</CODE></A>. If <code>OutputCommitter</code> is not
469  a <code>FileOutputCommitter</code>, the task's temporary output
470  directory is same as <A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getOutputPath(org.apache.hadoop.mapred.JobConf)"><CODE>getOutputPath(JobConf)</CODE></A> i.e.
471  <tt>${mapred.output.dir}$</tt></p>
472 
473 <p>Some applications need to create/write-to side-files, which differ from
474 the actual job-outputs.
475 
476 <p>In such cases there could be issues with 2 instances of the same TIP
477 (running simultaneously e.g. speculative tasks) trying to open/write-to the
478 same file (path) on HDFS. Hence the application-writer will have to pick
479 unique names per task-attempt (e.g. using the attemptid, say
480 <tt>attempt_200709221812_0001_m_000000_0</tt>), not just per TIP.</p> 
481 
482 <p>To get around this the Map-Reduce framework helps the application-writer
483 out by maintaining a special
484 <tt>${mapred.output.dir}/_temporary/_${taskid}</tt> 
485 sub-directory for each task-attempt on HDFS where the output of the
486 task-attempt goes. On successful completion of the task-attempt the files
487 in the <tt>${mapred.output.dir}/_temporary/_${taskid}</tt> (only)
488 are <i>promoted</i> to <tt>${mapred.output.dir}</tt>. Of course, the
489 framework discards the sub-directory of unsuccessful task-attempts. This
490 is completely transparent to the application.</p>
491 
492 <p>The application-writer can take advantage of this by creating any
493 side-files required in <tt>${mapred.work.output.dir}</tt> during execution
494 of his reduce-task i.e. via <A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"><CODE>getWorkOutputPath(JobConf)</CODE></A>, and the
495 framework will move them out similarly - thus she doesn't have to pick
496 unique paths per task-attempt.</p>
497 
498 <p><i>Note</i>: the value of <tt>${mapred.work.output.dir}</tt> during
499 execution of a particular task-attempt is actually
500 <tt>${mapred.output.dir}/_temporary/_{$taskid}</tt>, and this value is
501 set by the map-reduce framework. So, just create any side-files in the
502 path  returned by <A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"><CODE>getWorkOutputPath(JobConf)</CODE></A> from map/reduce
503 task to take advantage of this feature.</p>
504 
505 <p>The entire discussion holds true for maps of jobs with
506 reducer=NONE (i.e. 0 reduces) since output of the map, in that case,
507 goes directly to HDFS.</p>
508<P>
509<DD><DL>
510</DL>
511</DD>
512<DD><DL>
513
514<DT><B>Returns:</B><DD>the <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> to the task's temporary output directory
515 for the map-reduce job.</DL>
516</DD>
517</DL>
518<HR>
519
520<A NAME="getTaskOutputPath(org.apache.hadoop.mapred.JobConf, java.lang.String)"><!-- --></A><H3>
521getTaskOutputPath</H3>
522<PRE>
523public static <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A> <B>getTaskOutputPath</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
524                                     <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)
525                              throws <A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></PRE>
526<DL>
527<DD>Helper function to create the task's temporary output directory and
528 return the path to the task's output file.
529<P>
530<DD><DL>
531</DL>
532</DD>
533<DD><DL>
534<DT><B>Parameters:</B><DD><CODE>conf</CODE> - job-configuration<DD><CODE>name</CODE> - temporary task-output filename
535<DT><B>Returns:</B><DD>path to the task's temporary output file
536<DT><B>Throws:</B>
537<DD><CODE><A HREF="http://java.sun.com/javase/6/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</A></CODE></DL>
538</DD>
539</DL>
540<HR>
541
542<A NAME="getUniqueName(org.apache.hadoop.mapred.JobConf, java.lang.String)"><!-- --></A><H3>
543getUniqueName</H3>
544<PRE>
545public static <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A> <B>getUniqueName</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
546                                   <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)</PRE>
547<DL>
548<DD>Helper function to generate a name that is unique for the task.
549
550 <p>The generated name can be used to create custom files from within the
551 different tasks for the job, the names for different tasks will not collide
552 with each other.</p>
553
554 <p>The given name is postfixed with the task type, 'm' for maps, 'r' for
555 reduces and the task partition number. For example, give a name 'test'
556 running on the first map o the job the generated name will be
557 'test-m-00000'.</p>
558<P>
559<DD><DL>
560</DL>
561</DD>
562<DD><DL>
563<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the configuration for the job.<DD><CODE>name</CODE> - the name to make unique.
564<DT><B>Returns:</B><DD>a unique name accross all tasks of the job.</DL>
565</DD>
566</DL>
567<HR>
568
569<A NAME="getPathForCustomFile(org.apache.hadoop.mapred.JobConf, java.lang.String)"><!-- --></A><H3>
570getPathForCustomFile</H3>
571<PRE>
572public static <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs">Path</A> <B>getPathForCustomFile</B>(<A HREF="../../../../org/apache/hadoop/mapred/JobConf.html" title="class in org.apache.hadoop.mapred">JobConf</A>&nbsp;conf,
573                                        <A HREF="http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true" title="class or interface in java.lang">String</A>&nbsp;name)</PRE>
574<DL>
575<DD>Helper function to generate a <A HREF="../../../../org/apache/hadoop/fs/Path.html" title="class in org.apache.hadoop.fs"><CODE>Path</CODE></A> for a file that is unique for
576 the task within the job output directory.
577
578 <p>The path can be used to create custom files from within the map and
579 reduce tasks. The path name will be unique for each task. The path parent
580 will be the job output directory.</p>ls
581
582 <p>This method uses the <A HREF="../../../../org/apache/hadoop/mapred/FileOutputFormat.html#getUniqueName(org.apache.hadoop.mapred.JobConf, java.lang.String)"><CODE>getUniqueName(org.apache.hadoop.mapred.JobConf, java.lang.String)</CODE></A> method to make the file name
583 unique for the task.</p>
584<P>
585<DD><DL>
586</DL>
587</DD>
588<DD><DL>
589<DT><B>Parameters:</B><DD><CODE>conf</CODE> - the configuration for the job.<DD><CODE>name</CODE> - the name for the file.
590<DT><B>Returns:</B><DD>a unique path accross all tasks of the job.</DL>
591</DD>
592</DL>
593<!-- ========= END OF CLASS DATA ========= -->
594<HR>
595
596
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