org.drools.compiler.lang.dsl.DefaultExpander Maven / Gradle / Ivy
/*
* Copyright 2005 JBoss Inc
*
* 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 org.drools.compiler.lang.dsl;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Formatter;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.drools.compiler.lang.Expander;
import org.drools.compiler.lang.ExpanderException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The default expander uses String templates to provide pseudo natural
* language, as well as general DSLs.
*
* For most people, this should do the job just fine.
*/
public class DefaultExpander
implements
Expander {
protected static transient Logger logger = LoggerFactory.getLogger(DefaultExpander.class);
private static final String ruleOrQuery =
"^(?: " + // alternatives rule...end, query...end
"\\p{Blank}*(rule\\b.+?^\\s*when\\b)" + // 1: rule, name, attributes. when starts a line
"(.*?) " + // 2: condition
"^(\\s*then) " + // 3: then starts a line
"(.*?) " + // 4: consequence
"(^\\s*end.*?$) " + // 5: end starts a line
"|\\s*(query\\s+ " +
"(?:\"[^\"]+\"|'[^']+'|\\S+) " +
"(?:\\s*\\([^)]+\\))?) " + // 6: query, name, arguments
"(.*?) " + // 7: condition
"(^\\s*end.*?$) " + // 8: end starts a line
")";
private static final Pattern finder =
Pattern.compile( ruleOrQuery,
Pattern.DOTALL | Pattern.MULTILINE | Pattern.COMMENTS );
private static final Pattern comments = Pattern.compile( "/\\*.*?\\*/", Pattern.DOTALL );
// This pattern finds a statement's modify body
private static final Pattern modifyFinder = Pattern.compile( "\\{(.*?)\\}" );
private static final String funcPatStr = "(?:!(uc|lc|ucfirst|num|.*))?";
// Pattern for finding a variable reference, restricted to Unicode letters and digits.
private static final Pattern varRefPat = Pattern.compile( "\\{([\\p{L}\\d]+)" + funcPatStr + "\\}" );
// Pattern for initial integer
private static final Pattern intPat = Pattern.compile( "^(-?\\d+).*$" );
private final List keywords = new LinkedList();
private final List condition = new LinkedList();
private final List consequence = new LinkedList();
private final List cleanup = new LinkedList();
private Map useKeyword;
private Map useWhen;
private Map useThen;
private List> substitutions;
private List errors = Collections.emptyList();
private boolean showResult = false;
private boolean showSteps = false;
private boolean showWhen = false;
private boolean showThen = false;
private boolean showKeyword = false;
private boolean showUsage = false;
/**
* Creates a new DefaultExpander
*/
public DefaultExpander() {
this.cleanup.add( new AntlrDSLMappingEntry( DSLMappingEntry.KEYWORD,
DSLMappingEntry.EMPTY_METADATA,
"expander {name}",
"",
"expander (.*?)",
"" ) );
}
/**
* Add the new mapping to this expander.
*
* @param mapping
*/
public void addDSLMapping(final DSLMapping mapping) {
for ( DSLMappingEntry entry : mapping.getEntries() ) {
if ( DSLMappingEntry.KEYWORD.equals( entry.getSection() ) ) {
this.keywords.add( entry );
} else if ( DSLMappingEntry.CONDITION.equals( entry.getSection() ) ) {
this.condition.add( entry );
} else if ( DSLMappingEntry.CONSEQUENCE.equals( entry.getSection() ) ) {
this.consequence.add( entry );
} else {
// if any, then add to them both condition and consequence
this.condition.add( entry );
this.consequence.add( entry );
}
}
if ( mapping.getOption( "result" ) ) showResult = true;
if ( mapping.getOption( "steps" ) ) showSteps = true;
if ( mapping.getOption( "keyword" ) ) showKeyword = true;
if ( mapping.getOption( "when" ) ) showWhen = true;
if ( mapping.getOption( "then" ) ) showThen = true;
if ( mapping.getOption( "usage" ) ) showUsage = true;
}
/**
* @inheritDoc
* @throws IOException
*/
public String expand(final Reader drlReader) throws IOException {
return this.expand( this.loadDrlFile( drlReader ) );
}
private void displayUsage(String what,
Map use) {
logger.info( "=== Usage of " + what + " ===" );
Formatter fmt = new Formatter( System.out );
for ( Map.Entry entry : use.entrySet() ) {
fmt.format( "%4d %s%n",
entry.getValue(),
entry.getKey() );
}
}
/**
* @inheritDoc
* @throws IOException
*/
public String expand(String drl) {
if ( showUsage ) {
useKeyword = new HashMap();
useWhen = new HashMap();
useThen = new HashMap();
}
drl = removeComments( drl );
drl = expandKeywords( drl );
drl = cleanupExpressions( drl );
final StringBuffer buf = expandConstructions( drl );
if ( showUsage ) {
displayUsage( "keyword",
useKeyword );
displayUsage( "when",
useWhen );
displayUsage( "then",
useThen );
}
if ( showResult ) {
StringBuffer show = new StringBuffer();
Formatter fmt = new Formatter( show );
int offset = 0;
int nlPos;
int iLine = 1;
while ( (nlPos = buf.indexOf( "\n",
offset )) >= 0 ) {
fmt.format( "%4d %s%n",
iLine++,
buf.substring( offset,
nlPos ) );
offset = nlPos + 1;
}
logger.info( "=== DRL xpanded from DSLR ===" );
logger.info( show.toString() );
logger.info( "=============================" );
}
return buf.toString();
}
private static final String nl = System.getProperty( "line.separator" );
private static int countNewlines(final String drl,
int start,
int end) {
int count = 0;
int pos = start;
while ( (pos = drl.indexOf( nl,
pos )) >= 0 ) {
// logger.info( "pos at " + pos );
if ( pos >= end ) break;
pos += nl.length();
count++;
}
return count;
}
/**
* Expand constructions like rules and queries
*
* @param drl
* @return
*/
private StringBuffer expandConstructions(final String drl) {
// display keys if requested
if ( showKeyword ) {
for ( DSLMappingEntry entry : this.keywords ) {
logger.info( "keyword: " + entry.getMappingKey() );
logger.info( " " + entry.getKeyPattern() );
}
}
if ( showWhen ) {
for ( DSLMappingEntry entry : this.condition ) {
logger.info( "when: " + entry.getMappingKey() );
logger.info( " " + entry.getKeyPattern() );
// logger.info( " " + entry.getValuePattern() );
}
}
if ( showThen ) {
for ( DSLMappingEntry entry : this.consequence ) {
logger.info( "then: " + entry.getMappingKey() );
logger.info( " " + entry.getKeyPattern() );
}
}
// parse and expand specific areas
final Matcher m = finder.matcher( drl );
final StringBuffer buf = new StringBuffer();
int drlPos = 0;
int linecount = 0;
while ( m.find() ) {
final StringBuilder expanded = new StringBuilder();
int newPos = m.start();
linecount += countNewlines( drl,
drlPos,
newPos );
drlPos = newPos;
String constr = m.group().trim();
if ( constr.startsWith( "rule" ) ) {
String headerFragment = m.group( 1 );
expanded.append( headerFragment ); // adding rule header and attributes
String lhsFragment = m.group( 2 );
expanded.append( this.expandLHS( lhsFragment,
linecount + countNewlines( drl,
drlPos,
m.start( 2 ) ) + 1 ) );
String thenFragment = m.group( 3 );
expanded.append( thenFragment ); // adding "then" header
String rhsFragment = this.expandRHS( m.group( 4 ),
linecount + countNewlines( drl,
drlPos,
m.start( 4 ) ) + 1 );
expanded.append( rhsFragment );
expanded.append( m.group( 5 ) ); // adding rule trailer
} else if ( constr.startsWith( "query" ) ) {
String fragment = m.group( 6 );
expanded.append( fragment ); // adding query header and attributes
String lhsFragment = this.expandLHS( m.group( 7 ),
linecount + countNewlines( drl,
drlPos,
m.start( 7 ) ) + 1 );
expanded.append( lhsFragment );
expanded.append( m.group( 8 ) ); // adding query trailer
} else {
// strange behavior
this.addError( new ExpanderException( "Unable to expand statement: " + constr,
0 ) );
}
m.appendReplacement( buf,
Matcher.quoteReplacement( expanded.toString() ) );
}
m.appendTail( buf );
return buf;
}
/**
* Clean up constructions that exists only in the unexpanded code
*
* @param drl
* @return
*/
private String cleanupExpressions(String drl) {
// execute cleanup
for ( final DSLMappingEntry entry : this.cleanup ) {
drl = entry.getKeyPattern().matcher( drl ).replaceAll( entry.getValuePattern() );
}
return drl;
}
// private int countAll( Matcher matcher ){
// int n = 0;
// while( matcher.find() ){
// n++;
// }
// return n;
// }
private String removeComments(String drl) {
return comments.matcher(drl).replaceAll("");
}
/**
* Expand all configured keywords
*
* @param drl
* @return
*/
private String expandKeywords(String drl) {
substitutions = new ArrayList>();
// apply all keywords templates
drl = substitute( drl,
this.keywords,
0,
useKeyword,
false );
substitutions = null;
return drl;
}
private Pattern letterPat = Pattern.compile( "\\p{L}" );
private String applyFunc(String theFunc,
String theValue) {
if ( theFunc != null ) {
if ( "uc".equals( theFunc ) ) {
theValue = theValue.toUpperCase();
} else if ( "lc".equals( theFunc ) ) {
theValue = theValue.toLowerCase();
} else if ( "ucfirst".equals( theFunc ) ) {
Matcher letterMat = letterPat.matcher( theValue );
if ( letterMat.find() ) {
int pos = letterMat.start();
theValue = theValue.substring( 0,
pos ) +
theValue.substring( pos,
pos + 1 ).toUpperCase() +
theValue.substring( pos + 1 ).toLowerCase();
}
} else if ( theFunc.startsWith( "num" ) ) {
// kill all non-digits, but keep '-'
String numStr = theValue.replaceAll( "[^-\\d]+",
"" );
try {
long numLong = Long.parseLong( numStr );
if ( theValue.matches( "^.*[.,]\\d\\d(?:\\D.*|$)" ) ) {
numStr = Long.toString( numLong );
theValue = numStr.substring( 0,
numStr.length() - 2 ) + '.' + numStr.substring( numStr.length() - 2 );
} else {
theValue = Long.toString( numLong );
}
} catch ( NumberFormatException nfe ) {
// silently ignore - keep the value as it is
}
} else {
StringTokenizer strTok = new StringTokenizer( theFunc,
"?/",
true );
boolean compare = true;
int toks = strTok.countTokens();
while ( toks >= 4 ) {
String key = strTok.nextToken();
String qmk = strTok.nextToken(); // '?'
String val = strTok.nextToken(); // to use
String sep = strTok.nextToken(); // '/'
if ( key.equals( theValue ) ) {
theValue = val;
break;
}
toks -= 4;
if ( toks < 4 ) {
theValue = strTok.nextToken();
break;
}
}
}
}
return theValue;
}
/**
* Perform the substitutions.
*
* @param exp
* a DSLR source line to be expanded
* @param entries
* the appropriate DSL keys and values
* @param line
* line number
* @param use
* map for registering use
* @return the expanden line
*/
private String substitute(String exp,
List entries,
int line,
Map use,
boolean showSingleSteps) {
if ( entries.size() == 0 ) {
if ( line > 0 ) {
this.addError( new ExpanderException( "No mapping entries for expanding: " + exp,
line ) );
}
return exp;
}
if ( showSingleSteps ) {
logger.info( "to expand: |" + exp + "|" );
}
Map key2value = new HashMap();
for ( final DSLMappingEntry entry : entries ) {
Map vars = entry.getVariables();
String mappingKey = entry.getMappingKey();
String vp = entry.getValuePattern();
Pattern kp = entry.getKeyPattern();
Matcher m = kp.matcher( exp );
int startPos = 0;
boolean match;
Integer count;
if ( showUsage ) {
count = use.get( mappingKey );
if ( count == null ) use.put( mappingKey, 0 );
}
while ( startPos < exp.length() && m.find( startPos ) ) {
match = true;
if ( showSingleSteps ) {
logger.info( " matches: " + kp.toString() );
}
if ( showUsage ) {
use.put( mappingKey,
use.get( mappingKey ) + 1 );
}
// Replace the range of group 0.
String target = m.group( 0 );
if ( !vars.keySet().isEmpty() ) {
// Build a pattern matching any variable enclosed in braces.
StringBuilder sb = new StringBuilder();
String del = "\\{(";
for ( String key : vars.keySet() ) {
sb.append( del ).append( Pattern.quote( key ) );
del = "|";
}
sb.append( ")" ).append( funcPatStr ).append( "\\}" );
Pattern allkeyPat = Pattern.compile( sb.toString() );
vp = entry.getValuePattern();
Matcher allkeyMat = allkeyPat.matcher( vp );
// While the pattern matches, get the actual key and replace by '$' + index
while ( allkeyMat.find() ) {
String theKey = allkeyMat.group( 1 );
String theFunc = allkeyMat.group( 2 );
String foundValue = m.group( vars.get( theKey ) );
String theValue = applyFunc( theFunc,
foundValue );
String newVp = vp.substring( 0,
allkeyMat.start() ) + theValue + vp.substring( allkeyMat.end() );
allkeyMat.reset( newVp );
key2value.put( theKey,
foundValue );
if (newVp.equals(vp)) {
break;
} else {
vp = newVp;
}
}
}
// Try to find any matches from previous lines.
Matcher varRefMat = varRefPat.matcher( vp );
while ( varRefMat.find() ) {
String theKey = varRefMat.group( 1 );
String theFunc = varRefMat.group( 2 );
for ( int ientry = substitutions.size() - 1; ientry >= 0; ientry-- ) {
String foundValue = substitutions.get( ientry ).get( theKey );
if ( foundValue != null ) {
String theValue = applyFunc( theFunc,
foundValue );
// replace it
vp = vp.substring( 0,
varRefMat.start() ) + theValue + vp.substring( varRefMat.end() );
varRefMat.reset( vp );
break;
}
}
}
// add the new set of substitutions
if ( key2value.size() > 0 ) {
substitutions.add( key2value );
}
// now replace the target
exp = exp.substring( 0,
m.start() ) + vp + exp.substring( m.end() );
if ( match && showSingleSteps ) {
logger.info( " result: |" + exp + "|" );
}
startPos = m.start() + vp.length();
m.reset( exp );
}
}
return exp;
}
/**
* Expand LHS for a construction
*
* @param lhs
* @param lineOffset
* @return
*/
private String expandLHS(final String lhs,
int lineOffset) {
substitutions = new ArrayList>();
// logger.info( "*** LHS>" + lhs + "<" );
final StringBuilder buf = new StringBuilder();
final String[] lines = lhs.split( "\n",
-1 ); // since we assembled the string, we know line breaks are \n
final String[] expanded = new String[lines.length]; // buffer for expanded lines
int lastExpanded = -1;
int lastPattern = -1;
for ( int i = 0; i < lines.length - 1; i++ ) {
final String trimmed = lines[i].trim();
expanded[++lastExpanded] = lines[i];
if ( trimmed.length() == 0 || trimmed.startsWith( "#" ) || trimmed.startsWith( "//" ) ) {
// comments - do nothing
} else if ( trimmed.startsWith( ">" ) ) {
// passthrough code - simply remove the passthrough mark character
expanded[lastExpanded] = lines[i].replaceFirst( ">",
" " );
lastPattern = lastExpanded;
} else {
// regular expansion - expand the expression
expanded[lastExpanded] =
substitute( expanded[lastExpanded],
this.condition,
i + lineOffset,
useWhen,
showSteps );
// do we need to report errors for that?
if ( lines[i].equals( expanded[lastExpanded] ) ) {
// report error
this.addError( new ExpanderException( "Unable to expand: " + lines[i].replaceAll( "[\n\r]",
"" ).trim(),
i + lineOffset ) );
}
// but if the original starts with a "-", it means we need to add it
// as a constraint to the previous pattern
if ( trimmed.startsWith( "-" ) && (!lines[i].equals( expanded[lastExpanded] )) ) {
if ( lastPattern >= 0 ) {
ConstraintInformation c = ConstraintInformation.findConstraintInformationInPattern( expanded[lastPattern] );
if ( c.start > -1 ) {
// rebuilding previous pattern structure
expanded[lastPattern] = expanded[lastPattern].substring( 0,
c.start ) + c.constraints + ((c.constraints.trim().length() == 0) ? "" : ", ") + expanded[lastExpanded].trim() + expanded[lastPattern].substring( c.end );
} else {
// error, pattern not found to add constraint to
this.addError( new ExpanderException( "No pattern was found to add the constraint to: " + lines[i].trim(),
i + lineOffset ) );
}
}
lastExpanded--;
} else {
lastPattern = lastExpanded;
}
}
}
for ( int i = 0; i <= lastExpanded; i++ ) {
buf.append( expanded[i] );
buf.append( "\n" );
}
return buf.toString();
}
/**
* Expand RHS for rules
*
* @param lhs
* @return
*/
private String expandRHS(final String lhs,
int lineOffset) {
final StringBuilder buf = new StringBuilder();
final String[] lines = lhs.split( "\n",
-1 ); // since we assembled the string, we know line breaks are \n
final String[] expanded = new String[lines.length]; // buffer for expanded lines
int lastExpanded = -1;
int lastPattern = -1;
for ( int i = 0; i < lines.length - 1; i++ ) {
final String trimmed = lines[i].trim();
expanded[++lastExpanded] = lines[i];
if ( trimmed.length() == 0 || trimmed.startsWith( "#" ) || trimmed.startsWith( "//" ) ) { // comments
buf.append( lines[i] );
} else if ( trimmed.startsWith( ">" ) ) {
// passthrough code
expanded[lastExpanded] = lines[i].replaceFirst( ">",
" " );
} else { // regular expansions
expanded[lastExpanded] =
substitute( expanded[lastExpanded],
this.consequence,
i + lineOffset,
useThen,
showSteps );
// do we need to report errors for that?
if ( lines[i].equals( expanded[lastExpanded] ) ) {
// report error
this.addError( new ExpanderException( "Unable to expand: " + lines[i],
i + lineOffset ) );
}
// If the original starts with a "-", it means we need to add it
// as a modify term to the previous pattern
if ( trimmed.startsWith( "-" ) && (!lines[i].equals( expanded[lastExpanded] )) ) {
int lastMatchStart = -1;
int lastMatchEnd = -1;
String modifiers = "";
if ( lastPattern >= 0 ) {
final Matcher m2 = modifyFinder.matcher( expanded[lastPattern] );
while ( m2.find() ) {
lastMatchStart = m2.start();
lastMatchEnd = m2.end();
modifiers = m2.group( 1 ).trim();
}
}
if ( lastMatchStart > -1 ) {
// rebuilding previous modify structure
expanded[lastPattern] = expanded[lastPattern].substring( 0,
lastMatchStart )
+ "{ " + modifiers +
((modifiers.length() == 0) ? "" : ", ") +
expanded[lastExpanded].trim() + " }" +
expanded[lastPattern].substring( lastMatchEnd );
} else {
// error, pattern not found to add constraint to
this.addError( new ExpanderException( "No modify was found to add the modifier to: " + lines[i].trim(),
i + lineOffset ) );
}
lastExpanded--;
} else {
lastPattern = lastExpanded;
}
}
}
for ( int i = 0; i <= lastExpanded; i++ ) {
buf.append( expanded[i] );
buf.append( "\n" );
}
if ( lines.length == 0 ) {
buf.append( "\n" );
}
return buf.toString();
}
// Reads the stream into a String
private String loadDrlFile(final Reader drl) throws IOException {
final StringBuilder buf = new StringBuilder();
final BufferedReader input = new BufferedReader( drl );
String line;
while ( (line = input.readLine()) != null ) {
buf.append( line );
buf.append( "\n" );
}
return buf.toString();
}
private void addError(final ExpanderException error) {
if ( this.errors == Collections.EMPTY_LIST ) {
this.errors = new LinkedList();
}
this.errors.add( error );
}
/**
* @inheritDoc
*/
public List getErrors() {
return this.errors;
}
/**
* @inheritDoc
*/
public boolean hasErrors() {
return !this.errors.isEmpty();
}
//Container for information relating to constraint substitution on LHS expansion
//where a DSL Sentence begins with "-". The pattern's constraints are deemed to
//be between the first "(" and related matching ")". The constraint can include
//other parenthesis.
private static class ConstraintInformation {
int start = -1;
int end = -1;
String constraints = "";
static ConstraintInformation findConstraintInformationInPattern(String pattern) {
ConstraintInformation ci = new ConstraintInformation();
int bracketCount = 0;
for ( int i = 0; i < pattern.length(); i++ ) {
char c = pattern.charAt( i );
if ( c == '(' ) {
if ( bracketCount == 0 ) {
ci.start = i + 1;
}
bracketCount++;
}
if ( c == ')' ) {
bracketCount--;
if ( bracketCount == 0 ) {
ci.end = i;
ci.constraints = pattern.substring( ci.start,
ci.end );
return ci;
}
}
}
return ci;
}
}
}
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