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    • org.mvel.util.CollectionParser Maven / Gradle / Ivy

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    /**
 * MVEL (The MVFLEX Expression Language)
 *
 * Copyright (C) 2007 Christopher Brock, MVFLEX/Valhalla Project and the Codehaus
 *
 * Licensed 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.mvel.util;

import static org.mvel.util.ParseTools.balancedCapture;
import static org.mvel.util.PropertyTools.createStringTrimmed;
import static org.mvel.util.PropertyTools.isIdentifierPart;

import static org.mvel.util.ParseTools.isWhitespace;
import static org.mvel.util.ParseTools.subCompileExpression;

import static java.lang.System.arraycopy;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * This is the inline collection sub-parser.  It produces a skeleton model of the collection which is in turn translated
 * into a sequenced AST to produce the collection efficiently at runtime, and passed off to one of the JIT's if
 * configured.
 *
 * @author Christopher Brock
 */
public class CollectionParser {
    private char[] property;

    private int cursor;
    private int length;
    private int start;

    private int type;

    public static final int LIST = 0;
    public static final int ARRAY = 1;
    public static final int MAP = 2;

    private static final Object[] EMPTY_ARRAY = new Object[0];

    public CollectionParser() {
    }

    public CollectionParser(int type) {
        this.type = type;
    }

    public Object parseCollection(char[] property, boolean subcompile) {
        this.cursor = 0;
        if ((this.length = (this.property = property).length) > 0)
            while (length > 0 && isWhitespace(property[length - 1]))
                length--;

        return parseCollection(subcompile);
    }


    private Object parseCollection(boolean subcompile) {
        if (length == 0) {
            if (type == LIST) return new ArrayList();
            else return EMPTY_ARRAY;
        }

        Map map = null;
        List list = null;
        String ex = null;

        if (type != -1) {
            switch (type) {
                case ARRAY:
                case LIST:
                    list = new ArrayList();
                    break;
                case MAP:
                    map = new HashMap();
                    break;
            }
        }

        Object curr = null;
        int newType = -1;

        for (; cursor < length; cursor++) {
            switch (property[cursor]) {
                case '{':
                    if (newType == -1) {
                        newType = ARRAY;
                    }

                case '[':
                    if (cursor > 0 && isIdentifierPart(property[cursor-1])) continue;
                    
                    if (newType == -1) {
                        newType = LIST;
                    }

                    /**
                     * Sub-parse nested collections.
                     */
                    Object o = new CollectionParser(newType).parseCollection(subset(property, (start = cursor) + 1,
                            cursor = balancedCapture(property, start, property[start])), subcompile);

                    if (type == MAP) {
                        map.put(curr, o);
                    }
                    else {
                        list.add(curr = o);
                    }


                    if ((start = ++cursor) < (length - 1) && property[cursor] == ',') {
                        start = cursor + 1;
                    }

                    continue;

                case '(':
                    cursor = balancedCapture(property, cursor, property[cursor]);

                    break;

                case '\"':
                case '\'':
                    cursor = balancedCapture(property, cursor, property[cursor]);

                    break;

                case ',':
                    if (type != MAP) {
                        list.add(ex = new String(property, start, cursor - start));
                    }
                    else {
                        map.put(curr, ex = createStringTrimmed(property, start, cursor - start));
                    }

                    if (subcompile) subCompileExpression(ex);

                    start = cursor + 1;

                    break;

                case ':':
                    if (type != MAP) {
                        map = new HashMap();
                        type = MAP;
                    }
                    curr = createStringTrimmed(property, start, cursor - start);

                    if (subcompile) subCompileExpression((String) curr);

                    start = cursor + 1;
                    break;

                case '.':
                    cursor++;
                    while (cursor != length && isWhitespace(property[cursor])) cursor++;
                    if (property[cursor] == '{') {
                        cursor = balancedCapture(property, cursor, '{');                        
                    }
                    break;
            }
        }

        if (start < length) {
            if (cursor < (length - 1)) cursor++;

            if (type == MAP) {
                map.put(curr, ex = createStringTrimmed(property, start, cursor - start));
            }
            else {
                if (cursor < length) cursor++;
                list.add(ex = createStringTrimmed(property, start, cursor - start));
            }

            if (subcompile) subCompileExpression(ex);
        }

        switch (type) {
            case MAP:
                return map;
            case ARRAY:
                return list.toArray();
            default:
                return list;
        }
    }

    private static char[] subset(char[] property, int start, int end) {
        while (start < (end - 1) && isWhitespace(property[start]))
            start++;

        char[] newA = new char[end - start];
        //arraycopy(property, start, newA, 0, end - start);
        for (int i = 0; i < newA.length; i++) {
            newA[i] = property[i + start];
        }

        return newA;
    }


    public int getCursor() {
        return cursor;
    }

}
    
    
    
    

    




    
    
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