| /* |
| * 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.iotdb.commons.schema.view.viewExpression.unary; |
| |
| import org.apache.iotdb.commons.schema.view.viewExpression.ViewExpression; |
| import org.apache.iotdb.commons.schema.view.viewExpression.ViewExpressionType; |
| import org.apache.iotdb.commons.schema.view.viewExpression.visitor.ViewExpressionVisitor; |
| |
| import org.apache.tsfile.utils.ReadWriteIOUtils; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import java.nio.ByteBuffer; |
| import java.util.regex.Pattern; |
| |
| public class LikeViewExpression extends UnaryViewExpression { |
| |
| // region member variables and init functions |
| private final String patternString; |
| private final Pattern pattern; |
| |
| private final boolean isNot; |
| |
| public LikeViewExpression(ViewExpression expression, String patternString, boolean isNot) { |
| super(expression); |
| this.patternString = patternString; |
| this.isNot = isNot; |
| pattern = this.compile(); |
| } |
| |
| public LikeViewExpression( |
| ViewExpression expression, String patternString, Pattern pattern, boolean isNot) { |
| super(expression); |
| this.patternString = patternString; |
| this.pattern = pattern; |
| this.isNot = isNot; |
| } |
| |
| public LikeViewExpression(ByteBuffer byteBuffer) { |
| super(ViewExpression.deserialize(byteBuffer)); |
| patternString = ReadWriteIOUtils.readString(byteBuffer); |
| isNot = ReadWriteIOUtils.readBool(byteBuffer); |
| pattern = compile(); |
| } |
| |
| public LikeViewExpression(InputStream inputStream) { |
| super(ViewExpression.deserialize(inputStream)); |
| try { |
| patternString = ReadWriteIOUtils.readString(inputStream); |
| isNot = ReadWriteIOUtils.readBool(inputStream); |
| pattern = compile(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| // endregion |
| |
| // region common interfaces that have to be implemented |
| @Override |
| public <R, C> R accept(ViewExpressionVisitor<R, C> visitor, C context) { |
| return visitor.visitLikeExpression(this, context); |
| } |
| |
| @Override |
| public ViewExpressionType getExpressionType() { |
| return ViewExpressionType.LIKE; |
| } |
| |
| @Override |
| public String toString(boolean isRoot) { |
| String basicString = |
| this.expression.toString(false) + (isNot ? "NOT LIKE " : "LIKE ") + this.patternString; |
| if (isRoot) { |
| return basicString; |
| } |
| return "( " + basicString + " )"; |
| } |
| |
| @Override |
| protected void serialize(ByteBuffer byteBuffer) { |
| super.serialize(byteBuffer); |
| ReadWriteIOUtils.write(patternString, byteBuffer); |
| ReadWriteIOUtils.write(isNot, byteBuffer); |
| } |
| |
| @Override |
| protected void serialize(OutputStream stream) throws IOException { |
| super.serialize(stream); |
| ReadWriteIOUtils.write(patternString, stream); |
| ReadWriteIOUtils.write(isNot, stream); |
| } |
| // endregion |
| |
| public String getPatternString() { |
| return patternString; |
| } |
| |
| public Pattern getPattern() { |
| return pattern; |
| } |
| |
| public boolean isNot() { |
| return isNot; |
| } |
| |
| /** |
| * This Method is for un-escaping strings except '\' before special string '%', '_', '\', because |
| * we need to use '\' to judge whether to replace this to regexp string |
| */ |
| private String unescapeString(String value) { |
| StringBuilder stringBuilder = new StringBuilder(); |
| for (int i = 0; i < value.length(); i++) { |
| String ch = String.valueOf(value.charAt(i)); |
| if ("\\".equals(ch)) { |
| if (i < value.length() - 1) { |
| String nextChar = String.valueOf(value.charAt(i + 1)); |
| if ("%".equals(nextChar) || "_".equals(nextChar) || "\\".equals(nextChar)) { |
| stringBuilder.append(ch); |
| } |
| if ("\\".equals(nextChar)) { |
| i++; |
| } |
| } |
| } else { |
| stringBuilder.append(ch); |
| } |
| } |
| return stringBuilder.toString(); |
| } |
| |
| /** |
| * The main idea of this part comes from |
| * https://codereview.stackexchange.com/questions/36861/convert-sql-like-to-regex/36864 |
| */ |
| private Pattern compile() { |
| String unescapeValue = unescapeString(patternString); |
| String specialRegexString = ".^$*+?{}[]|()"; |
| StringBuilder patternBuilder = new StringBuilder(); |
| patternBuilder.append("^"); |
| for (int i = 0; i < unescapeValue.length(); i++) { |
| String ch = String.valueOf(unescapeValue.charAt(i)); |
| if (specialRegexString.contains(ch)) { |
| ch = "\\" + unescapeValue.charAt(i); |
| } |
| if (i == 0 |
| || !"\\".equals(String.valueOf(unescapeValue.charAt(i - 1))) |
| || i >= 2 |
| && "\\\\" |
| .equals( |
| patternBuilder.substring( |
| patternBuilder.length() - 2, patternBuilder.length()))) { |
| patternBuilder.append(ch.replace("%", ".*?").replace("_", ".")); |
| } else { |
| patternBuilder.append(ch); |
| } |
| } |
| patternBuilder.append("$"); |
| return Pattern.compile(patternBuilder.toString()); |
| } |
| } |