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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.document.select;
import com.yahoo.document.BucketIdFactory;
import com.yahoo.document.select.parser.ParseException;
import com.yahoo.document.select.parser.SelectInput;
import com.yahoo.document.select.parser.SelectParser;
import com.yahoo.document.select.parser.TokenMgrException;
import com.yahoo.document.select.simple.SelectionParser;
/**
* This class is used to find out in which locations a document might be in, if
* it matches a given document selection string.
*
* @author <a href="mailto:humbe@yahoo-inc.com">Håkon Humberset</a>
*/
public class BucketSelector {
// A local reference to the factory used by the current application.
private BucketIdFactory factory;
/**
* The bucket selector needs to be instantiated to be used, as it will
* depend on config.
*
* @param factory The bucket factory is needed to get information of how
* bucket ids are put together.
*/
public BucketSelector(BucketIdFactory factory) {
this.factory = factory;
}
/**
* Get the set of buckets that may contain documents that match the given
* document selection, as long as the document selection does not result in
* an unknown set of buckets. If it does, <code>null</code> will be
* returned. This requires the caller to be aware of the meaning of these
* return values, but also removes the need for redundant space utilization
* when dealing with unknown bucket sets.
*
* @param selector The document selection string
* @return a list of buckets with arbitrary number of location bits set,
* <i>or</i>, <code>null</code> if the document selection resulted
* in an unknown set
* @throws ParseException if <code>selector</code> couldn't be parsed
*/
public BucketSet getBucketList(String selector) throws ParseException {
try {
SelectionParser simple = new SelectionParser();
if (simple.parse(selector) && (simple.getRemaining().length() == 0)) {
return simple.getNode().getBucketSet(factory);
} else {
SelectParser parser = new SelectParser(new SelectInput(selector));
return parser.expression().getBucketSet(factory);
}
} catch (TokenMgrException e) {
ParseException t = new ParseException();
throw (ParseException) t.initCause(e);
} catch (RuntimeException e) {
ParseException t = new ParseException(
"Unexpected exception while parsing '" + selector + "'.");
throw (ParseException) t.initCause(e);
}
}
}
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