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High-performance Java Dataframe with integrated columnar storage (fork of tablesaw)

There is a newer version: 0.9.1

package org.datavec.dataframe.api;

import org.datavec.dataframe.columns.ColumnReference;
import org.datavec.dataframe.filtering.AllOf;
import org.datavec.dataframe.filtering.AnyOf;
import org.datavec.dataframe.filtering.Filter;
import org.datavec.dataframe.filtering.IsFalse;
import org.datavec.dataframe.filtering.IsTrue;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * A static utility class designed to take some of the work, and verbosity, out of making queries.
 * 
 * It is intended to be imported statically in any class that will run queries as it makes them easier to write - and
 * read.
 */
public class QueryHelper {

    /**
     * Returns a column reference for a column with the given name. It will be resolved at query time by associating
     * it with a table. At construction time, the columnType it will resolve to is unknown.
     */
    public static ColumnReference column(String columnName) {
        return new ColumnReference(columnName);
    }

    public static Filter both(Filter a, Filter b) {
        List filterList = new ArrayList<>();
        filterList.add(a);
        filterList.add(b);
        return AllOf.allOf(filterList);
    }

    public static Filter allOf(Filter... filters) {
        return AllOf.allOf(filters);
    }

    public static Filter allOf(Collection filters) {
        return AllOf.allOf(filters);
    }

    public static Filter and(Filter... filters) {
        return AllOf.allOf(filters);
    }

    public static Filter and(Collection filters) {
        return AllOf.allOf(filters);
    }

    public static Filter not(Filter filter) {
        return IsFalse.isFalse(filter);
    }

    public static Filter isFalse(Filter filter) {
        return IsFalse.isFalse(filter);
    }

    public static Filter isTrue(Filter filter) {
        return IsTrue.isTrue(filter);
    }

    public static Filter either(Filter a, Filter b) {
        List filterList = new ArrayList<>();
        filterList.add(a);
        filterList.add(b);
        return AnyOf.anyOf(filterList);
    }

    public static Filter anyOf(Filter... filters) {
        return AnyOf.anyOf(filters);
    }

    public static Filter anyOf(Collection filters) {
        return AnyOf.anyOf(filters);
    }

    public static Filter or(Filter... filters) {
        return AnyOf.anyOf(filters);
    }

    public static Filter or(Collection filters) {
        return AnyOf.anyOf(filters);
    }

}