r.lang.CollectionUtils.java Source code

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Here is the source code for r.lang.CollectionUtils.java

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/*
 * R : A Computer Language for Statistical Data Analysis
 * Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 * Copyright (C) 1997--2008  The R Development Core Team
 * Copyright (C) 2003, 2004  The R Foundation
 * Copyright (C) 2010 bedatadriven
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package r.lang;

import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import r.lang.exception.EvalException;

public class CollectionUtils {

    private CollectionUtils() {
    }

    public static Function<SEXP, Integer> length() {
        return new Function<SEXP, Integer>() {
            @Override
            public Integer apply(SEXP input) {
                return input.length();
            }
        };
    }

    public static Function<AtomicVector, String> stringElementAt(final int index) {
        return new Function<AtomicVector, String>() {
            @Override
            public String apply(AtomicVector input) {
                return input.getElementAsString(index % input.length());
            }
        };
    }

    public static Predicate<SEXP> modePredicate(String mode) {
        if (mode.equals("any")) {
            return Predicates.alwaysTrue();
        } else if (mode.equals("function")) {
            return IS_FUNCTION;
        } else {
            throw new EvalException(" mode '%s' as a predicate is implemented.", mode);
        }
    }

    public static class TagName implements Function<PairList.Node, String> {
        @Override
        public String apply(PairList.Node input) {
            return ((Symbol) input.getTag()).getPrintName();
        }
    }

    public static final Predicate<SEXP> IS_FUNCTION = new Predicate<SEXP>() {
        @Override
        public boolean apply(SEXP input) {
            return input instanceof r.lang.Function;
        }
    };
}