org.apache.lucene.spatial.query.SpatialArgsParser.java Source code

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Here is the source code for org.apache.lucene.spatial.query.SpatialArgsParser.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.lucene.spatial.query;

import org.locationtech.spatial4j.context.SpatialContext;
import org.locationtech.spatial4j.exception.InvalidShapeException;
import org.locationtech.spatial4j.shape.Shape;

import java.text.ParseException;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;

/**
 * Parses a string that usually looks like "OPERATION(SHAPE)" into a {@link SpatialArgs}
 * object. The set of operations supported are defined in {@link SpatialOperation}, such
 * as "Intersects" being a common one. The shape portion is defined by WKT {@link org.locationtech.spatial4j.io.WktShapeParser},
 * but it can be overridden/customized via {@link #parseShape(String, org.locationtech.spatial4j.context.SpatialContext)}.
 * There are some optional name-value pair parameters that follow the closing parenthesis.  Example:
 * <pre>
 *   Intersects(ENVELOPE(-10,-8,22,20)) distErrPct=0.025
 * </pre>
 * <p>
 * In the future it would be good to support something at least semi-standardized like a
 * variant of <a href="http://docs.geoserver.org/latest/en/user/filter/ecql_reference.html#spatial-predicate">
 *   [E]CQL</a>.
 *
 * @lucene.experimental
 */
public class SpatialArgsParser {

    public static final String DIST_ERR_PCT = "distErrPct";
    public static final String DIST_ERR = "distErr";

    /** Writes a close approximation to the parsed input format. */
    static String writeSpatialArgs(SpatialArgs args) {
        StringBuilder str = new StringBuilder();
        str.append(args.getOperation().getName());
        str.append('(');
        str.append(args.getShape().toString());
        if (args.getDistErrPct() != null)
            str.append(" distErrPct=").append(String.format(Locale.ROOT, "%.2f%%", args.getDistErrPct() * 100d));
        if (args.getDistErr() != null)
            str.append(" distErr=").append(args.getDistErr());
        str.append(')');
        return str.toString();
    }

    /**
     * Parses a string such as "Intersects(ENVELOPE(-10,-8,22,20)) distErrPct=0.025".
     *
     * @param v   The string to parse. Mandatory.
     * @param ctx The spatial context. Mandatory.
     * @return Not null.
     * @throws IllegalArgumentException if the parameters don't make sense or an add-on parameter is unknown
     * @throws ParseException If there is a problem parsing the string
     * @throws InvalidShapeException When the coordinates are invalid for the shape
     */
    public SpatialArgs parse(String v, SpatialContext ctx) throws ParseException, InvalidShapeException {
        int idx = v.indexOf('(');
        int edx = v.lastIndexOf(')');

        if (idx < 0 || idx > edx) {
            throw new ParseException("missing parens: " + v, -1);
        }

        SpatialOperation op = SpatialOperation.get(v.substring(0, idx).trim());

        String body = v.substring(idx + 1, edx).trim();
        if (body.length() < 1) {
            throw new ParseException("missing body : " + v, idx + 1);
        }

        Shape shape = parseShape(body, ctx);
        SpatialArgs args = newSpatialArgs(op, shape);

        if (v.length() > (edx + 1)) {
            body = v.substring(edx + 1).trim();
            if (body.length() > 0) {
                Map<String, String> aa = parseMap(body);
                readNameValuePairs(args, aa);
                if (!aa.isEmpty()) {
                    throw new IllegalArgumentException("unused parameters: " + aa);
                }
            }
        }
        args.validate();
        return args;
    }

    protected SpatialArgs newSpatialArgs(SpatialOperation op, Shape shape) {
        return new SpatialArgs(op, shape);
    }

    protected void readNameValuePairs(SpatialArgs args, Map<String, String> nameValPairs) {
        args.setDistErrPct(readDouble(nameValPairs.remove(DIST_ERR_PCT)));
        args.setDistErr(readDouble(nameValPairs.remove(DIST_ERR)));
    }

    protected Shape parseShape(String str, SpatialContext ctx) throws ParseException {
        //return ctx.readShape(str);//still in Spatial4j 0.4 but will be deleted
        return ctx.readShapeFromWkt(str);
    }

    protected static Double readDouble(String v) {
        return v == null ? null : Double.valueOf(v);
    }

    protected static boolean readBool(String v, boolean defaultValue) {
        return v == null ? defaultValue : Boolean.parseBoolean(v);
    }

    /** Parses "a=b c=d f" (whitespace separated) into name-value pairs. If there
     * is no '=' as in 'f' above then it's short for f=f. */
    protected static Map<String, String> parseMap(String body) {
        Map<String, String> map = new HashMap<>();
        StringTokenizer st = new StringTokenizer(body, " \n\t");
        while (st.hasMoreTokens()) {
            String a = st.nextToken();
            int idx = a.indexOf('=');
            if (idx > 0) {
                String k = a.substring(0, idx);
                String v = a.substring(idx + 1);
                map.put(k, v);
            } else {
                map.put(a, a);
            }
        }
        return map;
    }
}