TextDelimited (Cascading 3.1.2-wip-62)

java.lang.Object
- cascading.scheme.Scheme<Properties,InputStream,OutputStream,LineNumberReader,PrintWriter>
- - cascading.scheme.local.TextDelimited

All Implemented Interfaces:

Traceable, Serializable
```
public class TextDelimited
extends Scheme<Properties,InputStream,OutputStream,LineNumberReader,PrintWriter>
```
Class TextDelimited provides direct support for delimited text files, like TAB (\t) or COMMA (,) delimited files. It also optionally allows for quoted values.
TextDelimited may also be used to skip the "header" in a file, where the header is defined as the very first line in every input file. That is, if the byte offset of the current line from the input is zero (0), that line will be skipped.
It is assumed if sink/source fields is set to either Fields.ALL or Fields.UNKNOWN and skipHeader or hasHeader is true, the field names will be retrieved from the header of the file and used during planning. The header will parsed with the same rules as the body of the file.
By default headers are not skipped.
TextDelimited may also be used to write a "header" in a file. The fields names for the header are taken directly from the declared fields. Or if the declared fields are Fields.ALL or Fields.UNKNOWN, the resolved field names will be used, if any.
By default headers are not written.
If hasHeaders is set to true on a constructor, both skipHeader and writeHeader will be set to true.
By default this Scheme is both strict and safe.
Strict meaning if a line of text does not parse into the expected number of fields, this class will throw a TapException. If strict is false, then Tuple will be returned with null values for the missing fields.
Safe meaning if a field cannot be coerced into an expected type, a null will be used for the value. If safe is false, a TapException will be thrown.
Also by default, quote strings are not searched for to improve processing speed. If a file is COMMA delimited but may have COMMA's in a value, the whole value should be surrounded by the quote string, typically double quotes (").
Note all empty fields in a line will be returned as null unless coerced into a new type.
This Scheme may source/sink Fields.ALL, when given on the constructor the new instance will automatically default to strict == false as the number of fields parsed are arbitrary or unknown. A type array may not be given either, so all values will be returned as Strings.
By default, all text is encoded/decoded as UTF-8. This can be changed via the charsetName constructor argument.
To override field and line parsing behaviors, sub-class DelimitedParser or provide a FieldTypeResolver implementation.
Note that there should be no expectation that TextDelimited, or specifically DelimitedParser, can handle all delimited and quoted combinations reliably. Attempting to do so would impair its performance and maintainability.
Further, it can be safely said any corrupted files will not be supported for obvious reasons. Corrupted files may result in exceptions or could cause edge cases in the underlying java regular expression engine.
A large part of Cascading was designed to help users cleans data. Thus the recommendation is to create Flows that are responsible for cleansing large data-sets when faced with the problem
DelimitedParser maybe sub-classed and extended if necessary.

See Also:
TextLine, Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

static String DEFAULT_CHARSET

Fields
Modifier and Type	Field and Description
`static String`	`DEFAULT_CHARSET`

Constructor Summary

Constructors
Constructor and Description
`TextDelimited()` Constructor TextDelimited creates a new TextDelimited instance sourcing `Fields.UNKNOWN`, sinking `Fields.ALL` and using TAB as the default delimiter.
`TextDelimited(boolean hasHeader, DelimitedParser delimitedParser)` Constructor TextDelimited creates a new TextDelimited instance sourcing `Fields.UNKNOWN`, sinking `Fields.ALL` and using the given delimitedParser instance for parsing.
`TextDelimited(boolean hasHeader, String delimiter)` Constructor TextDelimited creates a new TextDelimited instance sourcing `Fields.UNKNOWN`, sinking `Fields.ALL` and using TAB as the default delimiter.
`TextDelimited(boolean hasHeader, String delimiter, String quote)` Constructor TextDelimited creates a new TextDelimited instance sourcing `Fields.UNKNOWN`, sinking `Fields.ALL` and using TAB as the default delimiter.
`TextDelimited(DelimitedParser delimitedParser)` Constructor TextDelimited creates a new TextDelimited instance sourcing `Fields.UNKNOWN`, sinking `Fields.ALL` and using the given delimitedParser instance for parsing.
`TextDelimited(Fields fields)` Constructor TextDelimited creates a new TextDelimited instance with TAB as the default delimiter.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, DelimitedParser delimitedParser)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter, boolean strict, String quote, Class[] types, boolean safe)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter, boolean strict, String quote, Class[] types, boolean safe, String charsetName)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String charsetName, DelimitedParser delimitedParser)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter, String quote, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean skipHeader, boolean writeHeader, String delimiter, String quote, Class[] types, boolean safe)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, DelimitedParser delimitedParser)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, String quote)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, String quote, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, String quote, Class[] types, boolean safe)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, String quote, Class[] types, boolean safe, String charsetName)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, boolean hasHeader, String delimiter, String quote, String charsetName)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, String delimiter)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, String delimiter, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, String delimiter, String quote)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, String delimiter, String quote, Class[] types)` Constructor TextDelimited creates a new TextDelimited instance.
`TextDelimited(Fields fields, String delimiter, String quote, Class[] types, boolean safe)` Constructor TextDelimited creates a new TextDelimited instance.

Method Summary

Methods
Modifier and Type	Method and Description
`LineNumberReader`	`createInput(InputStream inputStream)`
`PrintWriter`	`createOutput(OutputStream outputStream)`
`String`	`getCharsetName()`
`String`	`getDelimiter()` Method getDelimiter returns the delimiter used to parse fields from the current line of text.
`String`	`getQuote()` Method getQuote returns the quote string, if any, used to encapsulate each field in a line to delimited text.
`boolean`	`isSymmetrical()`
`void`	`presentSinkFields(FlowProcess<? extends Properties> flowProcess, Tap tap, Fields fields)`
`void`	`presentSourceFields(FlowProcess<? extends Properties> process, Tap tap, Fields fields)`
`Fields`	`retrieveSourceFields(FlowProcess<? extends Properties> process, Tap tap)`
`void`	`setSinkFields(Fields sinkFields)`
`void`	`setSourceFields(Fields sourceFields)`
`void`	`sink(FlowProcess<? extends Properties> flowProcess, SinkCall<PrintWriter,OutputStream> sinkCall)`
`void`	`sinkCleanup(FlowProcess<? extends Properties> flowProcess, SinkCall<PrintWriter,OutputStream> sinkCall)`
`void`	`sinkConfInit(FlowProcess<? extends Properties> flowProcess, Tap<Properties,InputStream,OutputStream> tap, Properties conf)`
`void`	`sinkPrepare(FlowProcess<? extends Properties> flowProcess, SinkCall<PrintWriter,OutputStream> sinkCall)`
`boolean`	`source(FlowProcess<? extends Properties> flowProcess, SourceCall<LineNumberReader,InputStream> sourceCall)`
`void`	`sourceCleanup(FlowProcess<? extends Properties> flowProcess, SourceCall<LineNumberReader,InputStream> sourceCall)`
`void`	`sourceConfInit(FlowProcess<? extends Properties> flowProcess, Tap<Properties,InputStream,OutputStream> tap, Properties conf)`
`void`	`sourcePrepare(FlowProcess<? extends Properties> flowProcess, SourceCall<LineNumberReader,InputStream> sourceCall)`

Methods inherited from class cascading.scheme.Scheme
equals, getNumSinkParts, getSinkFields, getSourceFields, getTrace, hashCode, isSink, isSource, presentSinkFieldsInternal, presentSourceFieldsInternal, retrieveSinkFields, setNumSinkParts, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail
- DEFAULT_CHARSET
```
public static final String DEFAULT_CHARSET
```
  See Also:
  Constant Field Values

Constructor Detail

TextDelimited
```
public TextDelimited()
```
Constructor TextDelimited creates a new TextDelimited instance sourcing Fields.UNKNOWN, sinking Fields.ALL and using TAB as the default delimiter.
Use this constructor if the source and sink fields will be resolved during planning, for example, when using with a Checkpoint Tap.

TextDelimited
```
@ConstructorProperties(value={"hasHeader","delimiter"})
public TextDelimited(boolean hasHeader,
                                        String delimiter)
```
Constructor TextDelimited creates a new TextDelimited instance sourcing Fields.UNKNOWN, sinking Fields.ALL and using TAB as the default delimiter.
Use this constructor if the source and sink fields will be resolved during planning, for example, when using with a Checkpoint Tap.

Parameters:
hasHeader -
delimiter -

TextDelimited
```
@ConstructorProperties(value={"hasHeader","delimiter","quote"})
public TextDelimited(boolean hasHeader,
                                        String delimiter,
                                        String quote)
```
Constructor TextDelimited creates a new TextDelimited instance sourcing Fields.UNKNOWN, sinking Fields.ALL and using TAB as the default delimiter.
Use this constructor if the source and sink fields will be resolved during planning, for example, when using with a Checkpoint Tap.

Parameters:
hasHeader -
delimiter -
quote -

TextDelimited
```
@ConstructorProperties(value={"hasHeader","delimitedParser"})
public TextDelimited(boolean hasHeader,
                                        DelimitedParser delimitedParser)
```
Constructor TextDelimited creates a new TextDelimited instance sourcing Fields.UNKNOWN, sinking Fields.ALL and using the given delimitedParser instance for parsing.
Use this constructor if the source and sink fields will be resolved during planning, for example, when using with a Checkpoint Tap.

Parameters:
hasHeader -
delimitedParser -

TextDelimited
```
@ConstructorProperties(value="delimitedParser")
public TextDelimited(DelimitedParser delimitedParser)
```
Constructor TextDelimited creates a new TextDelimited instance sourcing Fields.UNKNOWN, sinking Fields.ALL and using the given delimitedParser instance for parsing.
Use this constructor if the source and sink fields will be resolved during planning, for example, when using with a Checkpoint Tap.
This constructor will set skipHeader and writeHeader values to true.

Parameters:
delimitedParser -

TextDelimited
```
@ConstructorProperties(value="fields")
public TextDelimited(Fields fields)
```
Constructor TextDelimited creates a new TextDelimited instance with TAB as the default delimiter.

Parameters:
fields - of type Fields