com.turn.splicer.tsdbutils.expression.Expressions.java Source code

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Here is the source code for com.turn.splicer.tsdbutils.expression.Expressions.java

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/**
 * Copyright 2015-2016 The Splicer Query Engine Authors
 *
 * 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 com.turn.splicer.tsdbutils.expression;

import com.turn.splicer.tsdbutils.TsQuery;

import java.util.List;

import com.google.common.base.Preconditions;

public class Expressions {

    public static ExpressionTree parse(String expr, List<String> metricQueries, TsQuery dataQuery) {
        Preconditions.checkNotNull(expr);
        if (expr.indexOf('(') == -1 || expr.indexOf(')') == -1) {
            throw new RuntimeException("Invalid Expression: " + expr);
        }

        ExprReader reader = new ExprReader(expr.toCharArray());
        reader.skipWhitespaces();

        String funcName = reader.readFuncName();
        Expression rootExpr = ExpressionFactory.getByName(funcName);
        if (rootExpr == null) {
            throw new RuntimeException("Could not find evaluator " + "for function '" + funcName + "'");
        }

        ExpressionTree root = new ExpressionTree(rootExpr, dataQuery);

        reader.skipWhitespaces();
        if (reader.peek() == '(') {
            reader.next();
            parse(reader, metricQueries, root, dataQuery);
        }

        return root;
    }

    private static void parse(ExprReader reader, List<String> metricQueries, ExpressionTree root,
            TsQuery dataQuery) {

        int parameterIndex = 0;
        reader.skipWhitespaces();
        if (reader.peek() != ')') {
            String param = reader.readNextParameter();
            parseParam(param, metricQueries, root, dataQuery, parameterIndex++);
        }

        while (true) {
            reader.skipWhitespaces();
            if (reader.peek() == ')') {
                return;
            } else if (reader.isNextSeq(",,")) {
                reader.skip(2); //swallow the ",," delimiter
                reader.skipWhitespaces();
                String param = reader.readNextParameter();
                parseParam(param, metricQueries, root, dataQuery, parameterIndex++);
            } else {
                throw new RuntimeException("Invalid delimiter in parameter " + "list at pos=" + reader.getMark()
                        + ", expr=" + reader.toString());
            }
        }
    }

    private static void parseParam(String param, List<String> metricQueries, ExpressionTree root, TsQuery dataQuery,
            int index) {
        if (param == null || param.length() == 0) {
            throw new RuntimeException("Invalid Parameter in " + "Expression");
        }

        if (param.indexOf('(') > 0 && param.indexOf(')') > 0) {
            // sub expression
            ExpressionTree subTree = parse(param, metricQueries, dataQuery);
            root.addSubExpression(subTree, index);
        } else if (param.indexOf(':') >= 0) {
            // metric query
            metricQueries.add(param);
            root.addSubMetricQuery(param, metricQueries.size() - 1, index);
        } else {
            // expression parameter
            root.addFunctionParameter(param);
        }
    }

}