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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.grouping.request;
import java.util.List;
import java.util.stream.Collectors;
/**
* This class represents a predefined bucket-function in a {@link GroupingExpression} for expressions that evaluate to a
* string.
*
* @author Simon Thoresen Hult
*/
public class StringPredefined extends PredefinedFunction {
/**
* Constructs a new instance of this class.
*
* @param exp The expression to evaluate, must evaluate to a string.
* @param arg1 The compulsory bucket.
* @param argN The optional buckets.
*/
public StringPredefined(GroupingExpression exp, StringBucket arg1, StringBucket... argN) {
this(null, null, exp, asList(arg1, argN));
}
private StringPredefined(String label, Integer level, GroupingExpression exp, List<StringBucket> args) {
super(label, level, exp, args);
}
@Override
public StringPredefined copy() {
return new StringPredefined(getLabel(),
getLevelOrNull(),
getArg(0),
args().stream()
.skip(1)
.map(StringBucket.class::cast)
.map(arg -> arg.copy())
.collect(Collectors.toList()));
}
@Override
public StringBucket getBucket(int i) {
return (StringBucket)getArg(i + 1);
}
/**
* Constructs a new instance of this class from a list of arguments.
*
* @param exp The expression to evaluate, must evaluate to a string.
* @param args The buckets to pass to the constructor.
* @return The created instance.
* @throws IllegalArgumentException Thrown if the list of buckets is empty.
*/
public static StringPredefined newInstance(GroupingExpression exp, List<StringBucket> args) {
if (args.isEmpty()) {
throw new IllegalArgumentException("Expected at least one bucket, got none.");
}
return new StringPredefined(null, null, exp, args);
}
}
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