io.virtdata.libbasics.shared.from_long.to_string.ListTemplate Maven / Gradle / Ivy

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With inspiration from other libraries

There is a newer version: 2.12.15

package io.virtdata.libbasics.shared.from_long.to_string;

import io.virtdata.annotations.Example;
import io.virtdata.annotations.ThreadSafeMapper;

import java.util.ArrayList;
import java.util.List;
import java.util.function.LongFunction;
import java.util.function.LongToIntFunction;

/**
 * Create a {@code List} based on two functions, the first to
 * determine the list size, and the second to populate the list with
 * string values. The input fed to the second function is incremented
 * between elements.
 */
@ThreadSafeMapper
public class ListTemplate implements LongFunction> {

    private final LongToIntFunction sizeFunc;
    private final LongFunction valueFunc;

    @Example({"ListTemplate(HashRange(3,7),NumberNameToString())", "create a list between 3 and 7 elements, with number names as the values"})
    public ListTemplate(LongToIntFunction sizeFunc,
                        LongFunction valueFunc) {
        this.sizeFunc = sizeFunc;
        this.valueFunc = valueFunc;
    }

    @Override
    public List apply(long value) {
        int size = sizeFunc.applyAsInt(value);
        List list = new ArrayList<>(size);
        for (int i = 0; i < size; i++) {
            list.add(valueFunc.apply(value+i));
        }
        return list;
    }
}