package org.drools.process.builder.dialect.mvel;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.compiler.DescrBuildError;
import org.drools.compiler.Dialect;
import org.drools.compiler.ReturnValueDescr;
import org.drools.process.builder.ReturnValueEvaluatorBuilder;
import org.drools.process.core.ContextResolver;
import org.drools.process.core.context.variable.VariableScope;
import org.drools.process.instance.impl.MVELReturnValueEvaluator;
import org.drools.process.instance.impl.ReturnValueConstraintEvaluator;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.builder.PackageBuildContext;
import org.drools.rule.builder.dialect.mvel.MVELDialect;
import org.drools.spi.KnowledgeHelper;
import org.drools.spi.ProcessContext;
public class MVELReturnValueEvaluatorBuilder
implements
ReturnValueEvaluatorBuilder {
public MVELReturnValueEvaluatorBuilder() {
}
public void build(final PackageBuildContext context,
final ReturnValueConstraintEvaluator constraintNode,
final ReturnValueDescr descr,
final ContextResolver contextResolver) {
String text = descr.getText();
try {
MVELDialect dialect = (MVELDialect) context.getDialect( "mvel" );
Map<String, Class<?>> variables = new HashMap<String,Class<?>>();
variables.put("context", ProcessContext.class);
variables.put("kcontext", org.drools.runtime.process.ProcessContext.class);
variables.put("drools", KnowledgeHelper.class);
Dialect.AnalysisResult analysis = dialect.analyzeBlock( context,
descr,
dialect.getInterceptors(),
text,
new Map[]{variables, context.getPackageBuilder().getGlobals()},
null );
List<String> variableNames = analysis.getNotBoundedIdentifiers();
if (contextResolver != null) {
for (String variableName: variableNames) {
VariableScope variableScope = (VariableScope) contextResolver.resolveContext(VariableScope.VARIABLE_SCOPE, variableName);
if (variableScope == null) {
context.getErrors().add(
new DescrBuildError(
context.getParentDescr(),
descr,
null,
"Could not find variable '" + variableName + "' for constraint '" + descr.getText() + "'" ) );
} else {
variables.put(variableName,
context.getDialect().getTypeResolver().resolveType(
variableScope.findVariable(variableName).getType().getStringType()));
}
}
}
MVELCompilationUnit unit = dialect.getMVELCompilationUnit( text,
analysis,
null,
null,
variables,
context );
MVELReturnValueEvaluator expr = new MVELReturnValueEvaluator( unit,
dialect.getId() );
expr.setVariableNames(variableNames);
constraintNode.setEvaluator( expr );
MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( dialect.getId() );
data.addCompileable( constraintNode,
expr );
expr.compile( context.getPackageBuilder().getRootClassLoader() );
} catch ( final Exception e ) {
context.getErrors().add( new DescrBuildError( context.getParentDescr(),
descr,
null,
"Unable to build expression for 'constraint' " + descr.getText() + "': " + e ) );
}
}
/**
* Allows newlines to demarcate expressions, as per MVEL command line.
* If expression spans multiple lines (ie inside an unbalanced bracket) then
* it is left alone.
* Uses character based iteration which is at least an order of magnitude faster then a single
* simple regex.
*/
public static String delimitExpressions(String s) {
StringBuilder result = new StringBuilder();
char[] cs = s.toCharArray();
int brace = 0;
int sqre = 0;
int crly = 0;
char lastNonWhite = ';';
for ( int i = 0; i < cs.length; i++ ) {
char c = cs[i];
switch ( c ) {
case '(' :
brace++;
break;
case '{' :
crly++;
break;
case '[' :
sqre++;
break;
case ')' :
brace--;
break;
case '}' :
crly--;
break;
case ']' :
sqre--;
break;
default :
break;
}
if ( (brace == 0 && sqre == 0 && crly == 0) && (c == '\n' || c == '\r') ) {
if ( lastNonWhite != ';' ) {
result.append( ';' );
lastNonWhite = ';';
}
} else if ( !Character.isWhitespace( c ) ) {
lastNonWhite = c;
}
result.append( c );
}
return result.toString();
}
}