package org.drools.rule.builder.dialect.java;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.drools.RuntimeDroolsException;
import org.drools.base.TypeResolver;
import org.drools.compiler.FunctionError;
import org.drools.lang.descr.FunctionDescr;
import org.drools.rule.LineMappings;
import org.drools.rule.Package;
import org.drools.rule.builder.FunctionBuilder;
import org.drools.util.StringUtils;
import org.mvel.TemplateInterpreter;
public class JavaFunctionBuilder
implements
FunctionBuilder {
// private static final StringTemplateGroup functionGroup = new StringTemplateGroup( new InputStreamReader( JavaFunctionBuilder.class.getResourceAsStream( "javaFunction.stg" ) ),
// AngleBracketTemplateLexer.class );
private static final String template = StringUtils.readFileAsString( new InputStreamReader( JavaFunctionBuilder.class.getResourceAsStream( "javaFunction.mvel" ) ) );
public JavaFunctionBuilder() {
}
/* (non-Javadoc)
* @see org.drools.rule.builder.dialect.java.JavaFunctionBuilder#build(org.drools.rule.Package, org.drools.lang.descr.FunctionDescr, org.codehaus.jfdi.interpreter.TypeResolver, java.util.Map)
*/
public String build(final Package pkg,
final FunctionDescr functionDescr,
final TypeResolver typeResolver,
final Map lineMappings,
final List errors) {
final Map vars = new HashMap();
vars.put( "package",
pkg.getName() );
vars.put( "imports",
pkg.getImports() );
final List staticImports = new LinkedList();
for( Iterator it = pkg.getStaticImports().iterator(); it.hasNext(); ) {
final String staticImport = (String) it.next();
if( ! staticImport.startsWith( functionDescr.getClassName() ) ) {
staticImports.add( staticImport );
}
}
vars.put( "staticImports",
staticImports );
vars.put( "className",
StringUtils.ucFirst( functionDescr.getName() ) );
vars.put( "methodName",
functionDescr.getName() );
vars.put( "returnType",
functionDescr.getReturnType() );
vars.put( "parameterTypes",
functionDescr.getParameterTypes() );
vars.put( "parameterNames",
functionDescr.getParameterNames() );
// Check that all the parameters are resolvable
final Map params = new HashMap();
final List names = functionDescr.getParameterNames();
final List types = functionDescr.getParameterTypes();
try {
for ( int i = 0, size = names.size(); i < size; i++ ) {
params.put( names.get( i ),
typeResolver.resolveType( (String) types.get( i ) ) );
}
} catch ( final ClassNotFoundException e ) {
errors.add( new FunctionError( functionDescr,
e,
"unable to resolve type while building function" ) );
}
vars.put( "text",
functionDescr.getText() );
final String text = TemplateInterpreter.evalToString( template,
vars );
//System.out.println( text );
final BufferedReader reader = new BufferedReader( new StringReader( text ) );
String line = null;
final String lineStartsWith = " public static " + functionDescr.getReturnType() + " " + functionDescr.getName();
int offset = 0;
try {
while ( (line = reader.readLine()) != null ) {
offset++;
if ( line.startsWith( lineStartsWith ) ) {
break;
}
}
functionDescr.setOffset( offset );
} catch ( final IOException e ) {
// won't ever happen, it's just reading over a string.
throw new RuntimeDroolsException( "Error determining start offset with function" );
}
final String name = pkg.getName() + "." + StringUtils.ucFirst( functionDescr.getName() );
final LineMappings mapping = new LineMappings( name );
mapping.setStartLine( functionDescr.getLine() );
mapping.setOffset( functionDescr.getOffset() );
lineMappings.put( name,
mapping );
return text;
}
}