org.apache.hawq.pxf.service.rest

Class MetadataResource

java.lang.Object

org.apache.hawq.pxf.service.rest.RestResource

org.apache.hawq.pxf.service.rest.MetadataResource

public class MetadataResource
extends RestResource

Class enhances the API of the WEBHDFS REST server. Returns the metadata of a given hcatalog table.
Example for querying API FRAGMENTER from a web client:
curl -i "http://localhost:51200/pxf/{version}/Metadata/getTableMetadata?table=t1"
/pxf/ is made part of the path when there is a webapp by that name in tomcat.

Constructor Summary

Constructors

Constructor and Description
MetadataResource()

Method Summary

Modifier and Type	Method and Description
javax.ws.rs.core.Response	read(javax.servlet.ServletContext servletContext, javax.ws.rs.core.HttpHeaders headers, java.lang.String profile, java.lang.String pattern) This function queries the underlying store based on the given profile to get schema for items that match the given pattern metadata: Item name, field names, field types.

Methods inherited from class org.apache.hawq.pxf.service.rest.RestResource

convertToCaseInsensitiveMap

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MetadataResource

public MetadataResource()
                 throws java.io.IOException

Throws:

java.io.IOException

Method Detail

read

public javax.ws.rs.core.Response read(@Context
                                      javax.servlet.ServletContext servletContext,
                                      @Context
                                      javax.ws.rs.core.HttpHeaders headers,
                                      java.lang.String profile,
                                      java.lang.String pattern)
                               throws java.lang.Exception

This function queries the underlying store based on the given profile to get schema for items that match the given pattern metadata: Item name, field names, field types. The types are converted from the underlying types to HAWQ types. Unsupported types result in an error.
Response Examples:
For a table default.t1 with 2 fields (a int, b float) will be returned as: {"PXFMetadata":[{"item":{"path":"default","name":"t1"},"fields":[{"name":"a","type":"int"},{"name":"b","type":"float"}]}]}

Parameters:

servletContext - servlet context

headers - http headers

profile - based on this the metadata source can be inferred

pattern - table/file name or pattern in the given source

Returns:

JSON formatted response with metadata of each item that corresponds to the pattern

Throws:

java.lang.Exception - if connection to the source/catalog failed, item didn't exist for the pattern its type or fields are not supported