Interface TapMetaReader
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- All Known Implementing Classes:
TableSetTapMetaReader
,TapSchemaTapMetaReader
,VizierTapMetaReader
,Vosi11TapMetaReader
public interface TapMetaReader
Object which can acquire table metadata about a TAP service. Theread*
methods in this interface are in general time-consuming and should not be invoked on the event dispatch thread.This class deals with reading metadata from some external source, not with caching or managing the results, which should be done as required by clients of this class.
The only mandatory read method here is the top-level
readSchemas()
. This will supply all known schemas, but each schema may or may not have its tables filled in; those tables may or may not have their columns and foreign keys filled in. If the schemas do not have their tables filled in (schemaMeta.getTables()!=null
), thenreadTables
methods can be called to read the table metadata for each schema as required; that table metadata may then be cached in the schema object for later use. If the tables are filled in to start with, thenreadTables
may throw an UnsupportedOperationException. The same applies to filled in columns/foreign keys for table objects.- Since:
- 18 Mar 2015
- Author:
- Mark Taylor
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.lang.String
getMeans()
Returns a textual indication of the method or protocol this reader uses to acquire TAP metadata.java.lang.String
getSource()
Returns a textual indication of where the metadata is coming from, typically a URL.ColumnMeta[]
readColumns(TableMeta table)
Acquires metadata about columns in a given table from a TAP service.ForeignMeta[]
readForeignKeys(TableMeta table)
Acquires metadata about foreign keys in a given table from a TAP service.SchemaMeta[]
readSchemas()
Acquires metadata about schemas in a TAP service.TableMeta[]
readTables(SchemaMeta schema)
Acquires metadata about tables in a given schema from a TAP service.
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Method Detail
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readSchemas
SchemaMeta[] readSchemas() throws java.io.IOException
Acquires metadata about schemas in a TAP service.May be slow.
- Returns:
- schema metadata array
- Throws:
java.io.IOException
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readTables
TableMeta[] readTables(SchemaMeta schema) throws java.io.IOException
Acquires metadata about tables in a given schema from a TAP service.May be slow. May throw UnsupportedOperationException if not needed.
- Parameters:
schema
- schema containing tables; not altered by call- Returns:
- table metadata array
- Throws:
java.io.IOException
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readColumns
ColumnMeta[] readColumns(TableMeta table) throws java.io.IOException
Acquires metadata about columns in a given table from a TAP service.May be slow. May throw UnsupportedOperationException if not needed.
- Parameters:
table
- table containing columns; not altered by call- Returns:
- column metadata array
- Throws:
java.io.IOException
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readForeignKeys
ForeignMeta[] readForeignKeys(TableMeta table) throws java.io.IOException
Acquires metadata about foreign keys in a given table from a TAP service.May be slow. May throw UnsupportedOperationException if not needed.
- Parameters:
table
- table containing columns; not altered by call- Returns:
- foreign key metadata array
- Throws:
java.io.IOException
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getSource
java.lang.String getSource()
Returns a textual indication of where the metadata is coming from, typically a URL.- Returns:
- address of metadata
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getMeans
java.lang.String getMeans()
Returns a textual indication of the method or protocol this reader uses to acquire TAP metadata.- Returns:
- short description of metadata acquisition method
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