Class query.Field

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Class query.Field

java.lang.Object
   |
   +----query.ExpNode
           |
           +----query.Field

public class Field
extends ExpNode
implements STARTSnode, FilterNode, RankingNode

An ExpNode that represents a Field node in either a ranking or filter expression. Field nodes have no children and two properties: - field name: string - attribute set: string

Field(Query, String): Build a new field using the default attribute set.
Field(Query, String, String): Build a new field specifying the attribute set and field name.

Check(): Check this field node to see whether it is supported by the source in the query context.
ExtractTerms(Vector): noop for extracting terms from an expnode subtree.
GetAttributeSet(): Return the attribute set of this Field
GetFieldName(): Return the field name of this node
LanguageSupported_p(String): Predicate answering whether the specfied language is supported for this field.
Supported_p(): Predicate answering this field is supported by the source in the query context.
TranslateToFilter(): Translate this field node in the context of a source specific filter expression.
TranslateToRanking(): Translate this field node in the context of a source specific ranking expression.
Unparse(): Return the unparsed string represenation of this field node

Field

  public Field(Query query,
               String field)

Build a new field using the default attribute set.

Parameters:: query - the query context of this node; field - the field name for this field node.

Field

  public Field(Query query,
               String attributeSet,
               String field)

Build a new field specifying the attribute set and field name.

Parameters:: query - the query context for this node.; attributeSet - the attribute set; field - the field name

GetFieldName

  public String GetFieldName()

Return the field name of this node

Returns:: the string that is the field name (e.g. title)

GetAttributeSet

  public String GetAttributeSet()

Return the attribute set of this Field

Returns:: the String that is the attribute set (e.g., basic-1

Supported_p

  public boolean Supported_p()

Predicate answering this field is supported by the source in the query context.

Returns:: true or false depending on wheter this Field is supported by its Query context.

LanguageSupported_p

  public boolean LanguageSupported_p(String language)

Predicate answering whether the specfied language is supported for this field.

Parameters:: language - the language in ISO format
Returns:: true or false depending on whether the input language is supported for this field.

Unparse

  public String Unparse()

Return the unparsed string represenation of this field node

Returns:: the Sting representation of this Field node.
Overrides:: Unparse in class ExpNode

Check

  public ExpNode Check() throws UnsupportedQueryException

Check this field node to see whether it is supported by the source in the query context. If not supported, then return the "wildcard" field "any". If supported then return the field node

TranslateToFilter

  public ExpNode TranslateToFilter() throws SourceQueryException

Translate this field node in the context of a source specific filter expression.

Returns:: the sub-tree that is the source translated filter equivalanet of this Field subtree.
Throws: SourceQueryException: if there are translation errors.

TranslateToRanking

  public ExpNode TranslateToRanking() throws SourceQueryException

Translate this field node in the context of a source specific ranking expression.

Returns:: the subtree that is the source equivalent ranking expression for this Field sub-tree.
Throws: SourceQueryException: if there are translations errors.

ExtractTerms

  public void ExtractTerms(Vector termVector)

noop for extracting terms from an expnode subtree. Must be defined since the superclass defines it as abstract, but nothing ever descends from Fields so do nothing.

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