HBASE-14638 Move Jython info from the Wiki to the Ref Guide
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@ -27,14 +27,10 @@
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:icons: font
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:experimental:
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This chapter will cover access to Apache HBase either through non-Java languages, or through custom protocols.
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For information on using the native HBase APIs, refer to link:http://hbase.apache.org/apidocs/index.html[User API Reference] and the new <<hbase_apis,HBase APIs>> chapter.
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[[nonjava.jvm]]
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== Non-Java Languages Talking to the JVM
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Currently the documentation on this topic is in the link:http://wiki.apache.org/hadoop/Hbase[Apache HBase Wiki].
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See also the link:http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/thrift/package-summary.html#package_description[Thrift API Javadoc].
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This chapter will cover access to Apache HBase either through non-Java languages and
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through custom protocols. For information on using the native HBase APIs, refer to
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link:http://hbase.apache.org/apidocs/index.html[User API Reference] and the
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<<hbase_apis,HBase APIs>> chapter.
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== REST
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@ -640,6 +636,17 @@ To use Scala with HBase, your CLASSPATH must include HBase's classpath as well a
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the Scala JARs required by your code. First, use the following command on a server
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running the HBase RegionServer process, to get HBase's classpath.
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[[jython]]
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== Jython
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=== Setting the Classpath
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To use Jython with HBase, your CLASSPATH must include HBase's classpath as well as
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`jython.jar`. First, use the following command on a server running the HBase RegionServer
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process, to get HBase's classpath.
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>>>>>>> HBASE-14638 Move Jython info from the Wiki to the Ref Guide
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[source, bash]
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----
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$ ps aux |grep regionserver| awk -F 'java.library.path=' {'print $2'} | awk {'print $1'}
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@ -648,6 +655,7 @@ $ ps aux |grep regionserver| awk -F 'java.library.path=' {'print $2'} | awk {'pr
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----
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Set the `$CLASSPATH` environment variable to include the path you found in the previous
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<<<<<<< 12a718d0ca507c911f589d2926cfc408e4155b0e
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step, plus the path of `scala-library.jar` and each additional Scala-related JAR needed for
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your project.
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@ -704,3 +712,97 @@ val result=table.get(theget)
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val value=result.value()
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println(Bytes.toString(value))
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----
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=======
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step, plus the path to `jython.jar`.
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[source, bash]
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----
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$ export CLASSPATH=$CLASSPATH:/usr/lib/hadoop/lib/native:/usr/lib/hbase/lib/native/Linux-amd64-64:/path/to/jython.jar
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----
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Start a Jython shell with HBase and Hadoop JARs in the classpath:
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$ bin/hbase org.python.util.jython
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=== Jython Code Examples
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.Table Creation, Population, Get, and Delete with Jython
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====
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The following Jython code example creates a table, populates it with data, fetches
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the data, and deletes the table.
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[source,jython]
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----
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import java.lang
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from org.apache.hadoop.hbase import HBaseConfiguration, HTableDescriptor, HColumnDescriptor, HConstants
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from org.apache.hadoop.hbase.client import HBaseAdmin, HTable, Get
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from org.apache.hadoop.hbase.io import Cell, RowResult
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# First get a conf object. This will read in the configuration
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# that is out in your hbase-*.xml files such as location of the
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# hbase master node.
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conf = HBaseConfiguration()
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# Create a table named 'test' that has two column families,
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# one named 'content, and the other 'anchor'. The colons
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# are required for column family names.
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tablename = "test"
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desc = HTableDescriptor(tablename)
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desc.addFamily(HColumnDescriptor("content:"))
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desc.addFamily(HColumnDescriptor("anchor:"))
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admin = HBaseAdmin(conf)
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# Drop and recreate if it exists
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if admin.tableExists(tablename):
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admin.disableTable(tablename)
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admin.deleteTable(tablename)
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admin.createTable(desc)
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tables = admin.listTables()
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table = HTable(conf, tablename)
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# Add content to 'column:' on a row named 'row_x'
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row = 'row_x'
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update = Get(row)
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update.put('content:', 'some content')
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table.commit(update)
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# Now fetch the content just added, returns a byte[]
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data_row = table.get(row, "content:")
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data = java.lang.String(data_row.value, "UTF8")
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print "The fetched row contains the value '%s'" % data
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# Delete the table.
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admin.disableTable(desc.getName())
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admin.deleteTable(desc.getName())
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----
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====
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.Table Scan Using Jython
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====
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This example scans a table and returns the results that match a given family qualifier.
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[source, jython]
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----
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# Print all rows that are members of a particular column family
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# by passing a regex for family qualifier
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import java.lang
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from org.apache.hadoop.hbase import HBaseConfiguration
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from org.apache.hadoop.hbase.client import HTable
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conf = HBaseConfiguration()
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table = HTable(conf, "wiki")
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col = "title:.*$"
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scanner = table.getScanner([col], "")
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while 1:
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result = scanner.next()
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if not result:
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break
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print java.lang.String(result.row), java.lang.String(result.get('title:').value)
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----
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====
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