Subversion Repositories mkgmap

/*
 * Copyright (C) 2012.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 or
 * version 2 as published by the Free Software Foundation.
 *
 * 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.
 */

package uk.me.parabola.mkgmap.osmstyle.function;

import static uk.me.parabola.mkgmap.osmstyle.eval.NodeType.FUNCTION;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;

import uk.me.parabola.mkgmap.osmstyle.eval.ValueOp;
import uk.me.parabola.mkgmap.reader.osm.FeatureKind;
import uk.me.parabola.mkgmap.reader.osm.Node;
import uk.me.parabola.mkgmap.reader.osm.Relation;
import uk.me.parabola.mkgmap.reader.osm.Way;
import uk.me.parabola.mkgmap.scan.SyntaxException;

/**
 * The interface for all functions that can be used within a style file.<br>
 * The input parameter of a function is one element. The resulting value is a
 * string which can carry number values.
 * @author WanMil
 */
public abstract class StyleFunction extends ValueOp {

        protected int reqdNumParams = 0;
        protected List<String> params;
        protected FeatureKind kind;

        public StyleFunction(String value) {
                super(value);
                setType(FUNCTION);
        }

        public void setParams(List<String> params, FeatureKind kind) {
                if (params.size() != reqdNumParams)
                        throw new SyntaxException(String.format("Function %s takes %d parameters, %d given", getName(), reqdNumParams, params.size()));
                this.params = new ArrayList<>(params);
                this.kind = kind;
        }

        /**
         * Retrieves if the function accepts {@link Node} objects as input parameter.
         *
         * @return {@code true} {@link Node} objects are supported; {@code false} .. are not supported
         */
        public boolean supportsNode() {
                return false;
        }

        /**
         * Retrieves if the function accepts {@link Way} objects as input parameter.
         *
         * @return {@code true} {@link Way} objects are supported; {@code false} .. are not supported
         */
        public boolean supportsWay() {
                return false;
        }

        /**
         * Retrieves if the function accepts {@link Relation} objects as input parameter.
         *
         * @return {@code true} {@link Relation} objects are supported; {@code false} .. are not supported
         */
        public boolean supportsRelation() {
                return false;
        }

        /**
         * Retrieves the function name. This is the part without function brackets (). It is case sensitive but should be lower
         * case.
         *
         * @return the function name (e.g. length for length())
         */
        public String getName() {
                return getKeyValue();
        }

        @Override
        public String toString() {
                return getName() + "()";
        }

        /**
         * @return the tag keys evaluated in this function.
         */
        public Set<String> getUsedTags() {
                return Collections.emptySet();
        }

        /**
         *
         * @return an estimate for the complexity of this function, a value >= 1 and <= 10
         */
        public int getComplexity() {
                return 1;
        }
}