Class WarcFilter

java.lang.Object

org.netpreserve.jwarc.WarcFilter

All Implemented Interfaces:

Predicate<WarcRecord>

public class WarcFilter
extends Object
implements Predicate<WarcRecord>

Filter expressions for matching WARC records.

Simplified grammar for the expression language:

 
 expression = "(" expression ")"         ; grouping
            | "!(" expression ")"        ; boolean NOT
            | expression "&&" expression ; boolean AND
            | expression "||" expression ; boolean OR
            | field "==" string          ; string equality
            | field "!=" string          ; string inequality
            | field "=~" string          ; regex match
            | field "!~" string          ; regex non-match
            | field "==" number          ; integer equality
            | field "!=" number          ; integer inequality
            | field "<"  number          ; integer less-than
            | field "<=" number          ; integer less-than-or-equal
            | field ">"  number          ; integer greater-than
            | field ">=" number          ; integer greater-than-or-equal

 field = ":status"          ; HTTP response code psuedo-field
       | "http:" field-name ; HTTP header field
       | field-name         ; WARC header field

 string = '"' [^"]* '"'
 
 

Whitespace outside a string or field is ignored. Fields that do not exist are treated as an empty string when subject to string comparison. Fields that do not contain a valid number are treated as zero when subject to integer comparison.

Method Summary

Modifier and Type	Method	Description
static WarcFilter	compile(String expression)	Compiles a filter expression from a string.
boolean	test(WarcRecord warcRecord)
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.Predicate

and, negate, or

Method Details

compile

public static WarcFilter compile(String expression)

Compiles a filter expression from a string.

Throws:

WarcFilterException - when the expression contains a syntax error

test

public boolean test(WarcRecord warcRecord)

Specified by:

test in interface Predicate<WarcRecord>

toString

public String toString()

Overrides:

toString in class Object