public class LastModifiedMetadataChecksummer extends AbstractMetadataChecksummer
Default implementation of IMetadataChecksummer
for the
Norconex HTTP Collector which simply
returns the exact value of the "Last-Modified" HTTP header field, or
null
if not present.
You have the option to keep the checksum as a document metadata field.
When AbstractMetadataChecksummer.setKeep(boolean)
is true
, the checksum will be
stored in the target field name specified. If you do not specify any,
it stores it under the metadata field name
CrawlDocMetadata.CHECKSUM_METADATA
.
To use different fields (one or several) to constitute a checksum,
you can instead use the GenericMetadataChecksummer
.
<metadataChecksummer
class="com.norconex.collector.http.checksum.impl.LastModifiedMetadataChecksummer"
keep="[false|true]"
toField="(field to store checksum)"/>
<metadataChecksummer
keep="true"
toField="metaChecksum"/>
The above example will store the last modified date used for checksum purposes in a field called "metaChecksum".
Since 2.0.0, a self-closing
<metadataChecksummer/>
tag without any attributes
is used to disable checksum generation.
GenericMetadataChecksummer
Constructor and Description |
---|
LastModifiedMetadataChecksummer() |
Modifier and Type | Method and Description |
---|---|
protected String |
doCreateMetaChecksum(Properties metadata) |
boolean |
equals(Object other) |
int |
hashCode() |
boolean |
isDisabled()
Deprecated.
Since 2.0.0, not having a checksummer defined or
setting one explicitly to
null effectively disables
it. |
protected void |
loadChecksummerFromXML(XML xml) |
protected void |
saveChecksummerToXML(XML xml) |
void |
setDisabled(boolean disabled)
Deprecated.
Since 2.0.0, not having a checksummer defined or
setting one explicitly to
null effectively disable
it. |
String |
toString() |
createMetadataChecksum, getOnSet, getTargetField, getToField, isKeep, loadFromXML, saveToXML, setKeep, setOnSet, setTargetField, setToField
protected String doCreateMetaChecksum(Properties metadata)
doCreateMetaChecksum
in class AbstractMetadataChecksummer
@Deprecated public boolean isDisabled()
null
effectively disables
it.false
@Deprecated public void setDisabled(boolean disabled)
null
effectively disable
it.disabled
- argument is ignoredprotected void loadChecksummerFromXML(XML xml)
loadChecksummerFromXML
in class AbstractMetadataChecksummer
protected void saveChecksummerToXML(XML xml)
saveChecksummerToXML
in class AbstractMetadataChecksummer
public boolean equals(Object other)
equals
in class AbstractMetadataChecksummer
public int hashCode()
hashCode
in class AbstractMetadataChecksummer
public String toString()
toString
in class AbstractMetadataChecksummer
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