| /* |
| * 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 com.epam.dlab.core.parser; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.commons.jexl3.JexlBuilder; |
| import org.apache.commons.jexl3.JexlContext; |
| import org.apache.commons.jexl3.JexlEngine; |
| import org.apache.commons.jexl3.MapContext; |
| import org.apache.commons.jexl3.internal.Script; |
| import org.apache.commons.lang3.StringUtils; |
| |
| import com.epam.dlab.exceptions.InitializationException; |
| import com.epam.dlab.exceptions.ParseException; |
| import com.google.common.base.MoreObjects; |
| import com.google.common.base.MoreObjects.ToStringHelper; |
| |
| /** Evaluate condition for filtering source data. |
| */ |
| public class ConditionEvaluate { |
| |
| /** Names of columns for condition. */ |
| private String [] columnNames; |
| |
| /** Indexes of columns for condition. */ |
| private int [] columnIndexes; |
| |
| /** JEXL expression for evaluation. */ |
| private final Script expression; |
| |
| /** JEXL context to evaluate row. */ |
| private final JexlContext jexlContext; |
| |
| /** Instantiate the engine to evaluate condition. |
| * @param columnNames the list of column names. |
| * @param condition condition for filtering data. |
| * @throws InitializationException |
| */ |
| public ConditionEvaluate(List<String> columnNames, String condition) throws InitializationException { |
| //Replace : to . in column names |
| List<String> colNames = new ArrayList<>(columnNames.size()); |
| for (int i = 0; i < columnNames.size(); i++) { |
| String name = columnNames.get(i); |
| if (name.indexOf(':') > -1 && condition.indexOf(name) > -1) { |
| String newName = StringUtils.replaceChars(name, ':', '.'); |
| colNames.add(newName); |
| condition = StringUtils.replace(condition, name, newName); |
| } else { |
| colNames.add(name); |
| } |
| } |
| |
| try { |
| JexlEngine engine = new JexlBuilder().strict(true).silent(false).debug(true).create(); |
| expression = (Script) engine.createExpression(condition); |
| jexlContext = new MapContext(); |
| } catch (Exception e) { |
| throw new InitializationException("Cannot initialize JEXL engine for condition: " + condition + ". " + |
| e.getLocalizedMessage(), e); |
| } |
| |
| // Create mapping of columns for evaluations. |
| List<String> names = new ArrayList<>(); |
| List<Integer> indexes = new ArrayList<>(); |
| for (List<String> variableList : expression.getVariables()) { |
| String columnName = StringUtils.join(variableList, '.'); |
| int index = getColumnIndex(colNames, columnName); |
| if (index == -1) { |
| throw new InitializationException("Unknow source column name \"" + columnName + "\" in condition: " + |
| expression.getSourceText() + ". Known column names: " + StringUtils.join(columnNames, ", ") + "."); |
| } |
| names.add(columnName); |
| indexes.add(index); |
| } |
| |
| this.columnNames = new String[names.size()]; |
| this.columnIndexes = new int[indexes.size()]; |
| for (int i = 0; i < indexes.size(); i++) { |
| this.columnNames[i] = names.get(i); |
| this.columnIndexes[i] = indexes.get(i); |
| } |
| } |
| |
| /** Find and return the index of column in the given column list. |
| * @param columnNames the list of column names. |
| * @param columnName the name of column to find. |
| */ |
| private int getColumnIndex(List<String> columnNames, String columnName) { |
| for (int i = 0; i < columnNames.size(); i++) { |
| if (columnName.equals(columnNames.get(i))) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** Evaluate condition for given row. |
| * @param row the row to evaluate. |
| * @return <true> if condition is true. |
| * @throws ParseException if condition is not return boolean type. |
| */ |
| public boolean evaluate(List<String> row) throws ParseException { |
| for (int i = 0; i < columnNames.length; i++) { |
| jexlContext.set(columnNames[i], row.get(columnIndexes[i])); |
| } |
| Object value; |
| try { |
| value = expression.evaluate(jexlContext); |
| } catch (Exception e) { |
| throw new ParseException("Cannot evaluate condition: " + expression.getSourceText() + ". " + |
| e.getLocalizedMessage(), e); |
| } |
| if (value instanceof Boolean) { |
| return (Boolean)value; |
| } |
| throw new ParseException("Invalid condition: " + expression.getSourceText()); |
| } |
| |
| |
| /** Returns a string representation of the object. |
| * @param self the object to generate the string for (typically this), used only for its class name. |
| */ |
| public ToStringHelper toStringHelper(Object self) { |
| return MoreObjects.toStringHelper(self) |
| .add("columnNames", columnNames) |
| .add("columnIndexes", columnIndexes); |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this).toString(); |
| } |
| } |