apex-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From chinmaykolhatkar <...@git.apache.org>
Subject [GitHub] incubator-apex-malhar pull request: APEXMALHAR-2010 Add Tranform o...
Date Mon, 21 Mar 2016 06:26:27 GMT
Github user chinmaykolhatkar commented on a diff in the pull request:

    https://github.com/apache/incubator-apex-malhar/pull/209#discussion_r56785568
  
    --- Diff: library/src/main/java/com/datatorrent/lib/expression/JavaExpressionParser.java
---
    @@ -0,0 +1,179 @@
    +/**
    + * 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.datatorrent.lib.expression;
    +
    +import java.lang.reflect.Field;
    +import java.lang.reflect.Method;
    +import java.lang.reflect.Modifier;
    +import java.util.regex.Matcher;
    +import java.util.regex.Pattern;
    +
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import com.datatorrent.lib.util.KeyValPair;
    +
    +/**
    + * Defines how quasi-Java Expression should be parsed.
    + */
    +public class JavaExpressionParser implements Expression.ExpressionParser
    +{
    +  private static final Logger logger = LoggerFactory.getLogger(JavaExpressionParser.class);
    +
    +  private static final String GET = "get";
    +  private static final String IS = "is";
    +
    +  private String variablePlaceholderPattern = "\\{(.*?)\\}";
    +
    +  private String exprObjPlaceholder;
    +  private String codeObjPlaceholder;
    +
    +  public JavaExpressionParser()
    +  {
    +    // Fro kryo serialization.
    +  }
    +
    +  /**
    +   * {@inheritDoc}
    +   */
    +  @Override public String convertToCompilableExpression(String expression, Class<?>
objectType, Class<?> returnType)
    +  {
    +    if (expression.startsWith(".")) {
    +      expression = expression.substring(1);
    +    }
    +
    +    if (expression.isEmpty()) {
    +      throw new IllegalArgumentException("The getter expression: \"" + expression + "\"
is invalid.");
    +    }
    +
    +    Pattern entry = Pattern.compile(variablePlaceholderPattern);
    +    Matcher matcher = entry.matcher(expression);
    +    StringBuffer sb = new StringBuffer();
    +
    +    while (matcher.find()) {
    +      if (matcher.groupCount() == 1) {
    +        try {
    +          matcher.appendReplacement(sb, getObjectJavaExpression(matcher.group(1), objectType));
    +        } catch (NoSuchFieldException e) {
    +          throw new RuntimeException("Failed to parse the operand: " + matcher.group(1),
e);
    +        }
    +      } else {
    +        throw new RuntimeException("Invalid expression: " + matcher.group());
    +      }
    +    }
    +
    +    matcher.appendTail(sb);
    +
    +    if (sb.toString().equals(expression)) {
    +      // This is a simple expression. No object placeholder. create proper expression.
    +      if (!expression.startsWith("$.")) {
    +        expression = "$." + expression;
    +      }
    +      try {
    +        String tempExpr = getObjectJavaExpression(expression, objectType);
    +        sb.setLength(0);
    +        sb.append(tempExpr.replace("\\$", "$"));
    +      } catch (NoSuchFieldException e) {
    +        throw new RuntimeException("Failed to create expression.", e);
    +      }
    +    }
    +
    +    return "return ((" + returnType.getName().replace("$", "\\$") + ")" + sb.toString()
+ ");";
    +  }
    +
    +  /**
    +   * {@inheritDoc}
    +   */
    +  @Override public void setInputObjectPlaceholder(String exprObjPlaceholder, String codeObjPlaceholder)
    +  {
    +    this.exprObjPlaceholder = exprObjPlaceholder;
    +    this.codeObjPlaceholder = codeObjPlaceholder;
    +  }
    +
    +  private String getObjectJavaExpression(String exp, Class objectType) throws NoSuchFieldException
    --- End diff --
    
    This is removed.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message