/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.event.property;
import com.espertech.esper.client.PropertyAccessException;
import com.espertech.esper.epl.generated.EsperEPL2GrammarLexer;
import com.espertech.esper.epl.generated.EsperEPL2GrammarParser;
import com.espertech.esper.epl.parse.ASTUtil;
import com.espertech.esper.epl.parse.ExceptionConvertor;
import com.espertech.esper.epl.parse.NoCaseSensitiveStream;
import com.espertech.esper.epl.parse.ParseHelper;
import com.espertech.esper.type.IntValue;
import com.espertech.esper.type.StringValue;
import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.RecognitionException;
import org.antlr.v4.runtime.Token;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
/**
* Parser for property names that can be simple, nested, mapped or a combination of these.
* Uses ANTLR parser to parse.
*/
public class PropertyParser
{
private static final Log log = LogFactory.getLog(PropertyParser.class);
private static Set<String> keywordCache;
public static Property parseAndWalk(String property, boolean isRootedDynamic) {
return walk(parse(property), isRootedDynamic);
}
public static Property parseAndWalk(String property) {
return walk(parse(property), false);
}
/**
* Parse the given property name returning a Property instance for the property.
* @param isRootedDynamic is true to indicate that the property is already rooted in a dynamic
* property and therefore all child properties should be dynamic properties as well
* @return Property instance for property
*/
public static Property walk(EsperEPL2GrammarParser.StartEventPropertyRuleContext tree, boolean isRootedDynamic)
{
if (tree.eventProperty().eventPropertyAtomic().size() == 1) {
return makeProperty(tree.eventProperty().eventPropertyAtomic(0), isRootedDynamic);
}
EsperEPL2GrammarParser.EventPropertyContext propertyRoot = tree.eventProperty();
List<Property> properties = new LinkedList<Property>();
boolean isRootedInDynamic = isRootedDynamic;
for (EsperEPL2GrammarParser.EventPropertyAtomicContext atomic : propertyRoot.eventPropertyAtomic())
{
Property property = makeProperty(atomic, isRootedInDynamic);
if (property instanceof DynamicSimpleProperty) {
isRootedInDynamic = true;
}
properties.add(property);
}
return new NestedProperty(properties);
}
/**
* Parses a given property name returning an AST.
* @param propertyName to parse
* @return AST syntax tree
*/
public static EsperEPL2GrammarParser.StartEventPropertyRuleContext parse(String propertyName)
{
CharStream input;
try {
input = new NoCaseSensitiveStream(new StringReader(propertyName));
}
catch (IOException ex) {
throw new PropertyAccessException("IOException parsing property name '" + propertyName + '\'', ex);
}
EsperEPL2GrammarLexer lex = ParseHelper.newLexer(input);
CommonTokenStream tokens = new CommonTokenStream(lex);
tokens.fill();
EsperEPL2GrammarParser g = ParseHelper.newParser(tokens);
EsperEPL2GrammarParser.StartEventPropertyRuleContext r;
try {
r = g.startEventPropertyRule();
}
catch (RecognitionException e) {
return handleRecognitionEx(e, tokens, propertyName, g);
}
catch (RuntimeException e) {
if (log.isDebugEnabled()) {
log.debug("Error parsing property expression [" + propertyName + "]", e);
}
if (e.getCause() instanceof RecognitionException) {
return handleRecognitionEx( (RecognitionException) e.getCause(), tokens, propertyName, g);
}
else {
throw e;
}
}
return r;
}
private static EsperEPL2GrammarParser.StartEventPropertyRuleContext handleRecognitionEx(RecognitionException e, CommonTokenStream tokens, String propertyName, EsperEPL2GrammarParser g) {
// Check for keywords and escape each, parse again
String escapedPropertyName = escapeKeywords(tokens);
CharStream inputEscaped;
try {
inputEscaped = new NoCaseSensitiveStream(new StringReader(escapedPropertyName));
}
catch (IOException ex) {
throw new PropertyAccessException("IOException parsing property name '" + propertyName + '\'', ex);
}
EsperEPL2GrammarLexer lexEscaped = ParseHelper.newLexer(inputEscaped);
CommonTokenStream tokensEscaped = new CommonTokenStream(lexEscaped);
EsperEPL2GrammarParser gEscaped = ParseHelper.newParser(tokensEscaped);
try {
return gEscaped.startEventPropertyRule();
}
catch (Exception eEscaped)
{
}
throw ExceptionConvertor.convertProperty(e, propertyName, true, g);
}
private synchronized static String escapeKeywords(CommonTokenStream tokens) {
if (keywordCache == null) {
keywordCache = new HashSet<String>();
Set<String> keywords = ParseHelper.newParser(tokens).getKeywords();
for (String keyword : keywords) {
if (keyword.charAt(0) == '\'' && keyword.charAt(keyword.length() - 1) == '\'') {
keywordCache.add(keyword.substring(1, keyword.length() - 1));
}
}
}
StringWriter writer = new StringWriter();
for (Object token : tokens.getTokens()) // Call getTokens first before invoking tokens.size! ANTLR problem
{
Token t = (Token) token;
if (t.getType() == EsperEPL2GrammarLexer.EOF) {
break;
}
boolean isKeyword = keywordCache.contains(t.getText().toLowerCase());
if (isKeyword) {
writer.append('`');
writer.append(t.getText());
writer.append('`');
}
else {
writer.append(t.getText());
}
}
return writer.toString();
}
/**
* Returns true if the property is a dynamic property.
* @param ast property ast
* @return dynamic or not
*/
public static boolean isPropertyDynamic(EsperEPL2GrammarParser.StartEventPropertyRuleContext ast)
{
List<EsperEPL2GrammarParser.EventPropertyAtomicContext> ctxs = ast.eventProperty().eventPropertyAtomic();
for (EsperEPL2GrammarParser.EventPropertyAtomicContext ctx : ctxs) {
if (ctx.q != null || ctx.q1 != null) {
return true;
}
}
return false;
}
private static Property makeProperty(EsperEPL2GrammarParser.EventPropertyAtomicContext atomic, boolean isRootedInDynamic)
{
String prop = ASTUtil.unescapeDot(atomic.eventPropertyIdent().getText());
if (prop.length() == 0) {
throw new PropertyAccessException("Invalid zero-length string provided as an event property name");
}
if (atomic.lb != null) {
int index = IntValue.parseString(atomic.ni.getText());
if (!isRootedInDynamic && atomic.q == null) {
return new IndexedProperty(prop, index);
}
else {
return new DynamicIndexedProperty(prop, index);
}
}
else if (atomic.lp != null) {
String key = StringValue.parseString(atomic.s.getText());
if (!isRootedInDynamic && atomic.q == null) {
return new MappedProperty(prop, key);
}
else {
return new DynamicMappedProperty(prop, key);
}
}
else {
if (!isRootedInDynamic && atomic.q1 == null) {
return new SimpleProperty(prop);
}
else {
return new DynamicSimpleProperty(prop);
}
}
}
public static String unescapeBacktick(String unescapedPropertyName) {
if (unescapedPropertyName.startsWith("`") && unescapedPropertyName.endsWith("`")) {
return unescapedPropertyName.substring(1, unescapedPropertyName.length() - 1);
}
if (!unescapedPropertyName.contains("`")) {
return unescapedPropertyName;
}
// parse and render
Property property = PropertyParser.parseAndWalk(unescapedPropertyName);
if (property instanceof NestedProperty) {
StringWriter writer = new StringWriter();
property.toPropertyEPL(writer);
return writer.toString();
}
return unescapedPropertyName;
}
public static boolean isNestedPropertyWithNonSimpleLead(EsperEPL2GrammarParser.EventPropertyContext ctx) {
if (ctx.eventPropertyAtomic().size() == 1) {
return false;
}
EsperEPL2GrammarParser.EventPropertyAtomicContext atomic = ctx.eventPropertyAtomic().get(0);
return atomic.lb != null || atomic.lp != null || atomic.q1 != null;
}
}