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Groovy: A powerful, dynamic language for the JVM
/*
* 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 org.codehaus.groovy.transform;
import groovy.lang.GroovyClassLoader;
import groovy.lang.GroovyRuntimeException;
import groovy.transform.CompilationUnitAware;
import org.codehaus.groovy.GroovyBugError;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassCodeExpressionTransformer;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.DynamicVariable;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.expr.TupleExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.classgen.VariableScopeVisitor;
import org.codehaus.groovy.control.CompilationUnit;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
/**
* This class provides an AST Transformation to add a log field to a class.
*
* @author Guillaume Laforge
* @author Jochen Theodorou
* @author Dinko Srkoc
* @author Hamlet D'Arcy
* @author Raffaele Cigni
* @author Alberto Vilches Raton
* @author Tomasz Bujok
* @author Martin Ghados
* @author Matthias Cullmann
*/
@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
public class LogASTTransformation extends AbstractASTTransformation implements CompilationUnitAware {
/**
* This is just a dummy value used because String annotations values can not be null.
* It will be replaced by the fully qualified class name of the annotated class.
*/
public static final String DEFAULT_CATEGORY_NAME = "##default-category-name##";
private CompilationUnit compilationUnit;
public void visit(ASTNode[] nodes, final SourceUnit source) {
init(nodes, source);
AnnotatedNode targetClass = (AnnotatedNode) nodes[1];
AnnotationNode logAnnotation = (AnnotationNode) nodes[0];
final GroovyClassLoader classLoader = compilationUnit != null ? compilationUnit.getTransformLoader() : source.getClassLoader();
final LoggingStrategy loggingStrategy = createLoggingStrategy(logAnnotation, classLoader);
if (loggingStrategy == null) return;
final String logFieldName = lookupLogFieldName(logAnnotation);
final String categoryName = lookupCategoryName(logAnnotation);
if (!(targetClass instanceof ClassNode))
throw new GroovyBugError("Class annotation " + logAnnotation.getClassNode().getName() + " annotated no Class, this must not happen.");
final ClassNode classNode = (ClassNode) targetClass;
ClassCodeExpressionTransformer transformer = new ClassCodeExpressionTransformer() {
private FieldNode logNode;
@Override
protected SourceUnit getSourceUnit() {
return source;
}
public Expression transform(Expression exp) {
if (exp == null) return null;
if (exp instanceof MethodCallExpression) {
return transformMethodCallExpression(exp);
}
return super.transform(exp);
}
@Override
public void visitClass(ClassNode node) {
FieldNode logField = node.getField(logFieldName);
if (logField != null && logField.getOwner().equals(node)) {
addError("Class annotated with Log annotation cannot have log field declared", logField);
} else if (logField != null && !Modifier.isPrivate(logField.getModifiers())) {
addError("Class annotated with Log annotation cannot have log field declared because the field exists in the parent class: " + logField.getOwner().getName(), logField);
} else {
logNode = loggingStrategy.addLoggerFieldToClass(node, logFieldName, categoryName);
}
super.visitClass(node);
}
private Expression transformMethodCallExpression(Expression exp) {
MethodCallExpression mce = (MethodCallExpression) exp;
if (!(mce.getObjectExpression() instanceof VariableExpression)) {
return exp;
}
VariableExpression variableExpression = (VariableExpression) mce.getObjectExpression();
if (!variableExpression.getName().equals(logFieldName)
|| !(variableExpression.getAccessedVariable() instanceof DynamicVariable)) {
return exp;
}
String methodName = mce.getMethodAsString();
if (methodName == null) return exp;
if (usesSimpleMethodArgumentsOnly(mce)) return exp;
variableExpression.setAccessedVariable(logNode);
if (!loggingStrategy.isLoggingMethod(methodName)) return exp;
return loggingStrategy.wrapLoggingMethodCall(variableExpression, methodName, exp);
}
private boolean usesSimpleMethodArgumentsOnly(MethodCallExpression mce) {
Expression arguments = mce.getArguments();
if (arguments instanceof TupleExpression) {
TupleExpression tuple = (TupleExpression) arguments;
for (Expression exp : tuple.getExpressions()) {
if (!isSimpleExpression(exp)) return false;
}
return true;
}
return !isSimpleExpression(arguments);
}
private boolean isSimpleExpression(Expression exp) {
if (exp instanceof ConstantExpression) return true;
if (exp instanceof VariableExpression) return true;
return false;
}
};
transformer.visitClass(classNode);
// GROOVY-6373: references to 'log' field are normally already FieldNodes by now, so revisit scoping
new VariableScopeVisitor(sourceUnit, true).visitClass(classNode);
}
private String lookupLogFieldName(AnnotationNode logAnnotation) {
Expression member = logAnnotation.getMember("value");
if (member != null && member.getText() != null) {
return member.getText();
} else {
return "log";
}
}
private String lookupCategoryName(AnnotationNode logAnnotation) {
Expression member = logAnnotation.getMember("category");
if (member != null && member.getText() != null) {
return member.getText();
}
return DEFAULT_CATEGORY_NAME;
}
private LoggingStrategy createLoggingStrategy(AnnotationNode logAnnotation, GroovyClassLoader loader) {
String annotationName = logAnnotation.getClassNode().getName();
Class annotationClass;
try {
annotationClass = Class.forName(annotationName, false, loader);
} catch (Throwable e) {
throw new RuntimeException("Could not resolve class named " + annotationName);
}
Method annotationMethod;
try {
annotationMethod = annotationClass.getDeclaredMethod("loggingStrategy", (Class[]) null);
} catch (Throwable e) {
throw new RuntimeException("Could not find method named loggingStrategy on class named " + annotationName);
}
Object defaultValue;
try {
defaultValue = annotationMethod.getDefaultValue();
} catch (Throwable e) {
throw new RuntimeException("Could not find default value of method named loggingStrategy on class named " + annotationName);
}
if (!LoggingStrategy.class.isAssignableFrom((Class) defaultValue)) {
throw new RuntimeException("Default loggingStrategy value on class named " + annotationName + " is not a LoggingStrategy");
}
try {
Class strategyClass = (Class) defaultValue;
if (AbstractLoggingStrategy.class.isAssignableFrom(strategyClass)) {
return DefaultGroovyMethods.newInstance(strategyClass, new Object[]{loader});
} else {
return strategyClass.newInstance();
}
} catch (Exception e) {
return null;
}
}
/**
* A LoggingStrategy defines how to wire a new logger instance into an existing class.
* It is meant to be used with the @Log family of annotations to allow you to
* write your own Log annotation provider.
*/
public interface LoggingStrategy {
/**
* In this method, you are given a ClassNode, a field name and a category name, and you must add a new Field
* onto the class. Return the result of the ClassNode.addField operations.
*
* @param classNode the class that was originally annotated with the Log transformation.
* @param fieldName the name of the logger field
* @param categoryName the name of the logging category
* @return the FieldNode instance that was created and added to the class
*/
FieldNode addLoggerFieldToClass(ClassNode classNode, String fieldName, String categoryName);
boolean isLoggingMethod(String methodName);
String getCategoryName(ClassNode classNode, String categoryName);
Expression wrapLoggingMethodCall(Expression logVariable, String methodName, Expression originalExpression);
}
public static abstract class AbstractLoggingStrategy implements LoggingStrategy {
protected final GroovyClassLoader loader;
protected AbstractLoggingStrategy(final GroovyClassLoader loader) {
this.loader = loader;
}
protected AbstractLoggingStrategy() {
this(null);
}
public String getCategoryName(ClassNode classNode, String categoryName) {
if (categoryName.equals(DEFAULT_CATEGORY_NAME)) {
return classNode.getName();
}
return categoryName;
}
protected ClassNode classNode(String name) {
ClassLoader cl = loader == null ? this.getClass().getClassLoader() : loader;
try {
return ClassHelper.make(Class.forName(name, false, cl));
} catch (ClassNotFoundException e) {
throw new GroovyRuntimeException("Unable to load logging class", e);
}
}
}
public void setCompilationUnit(final CompilationUnit unit) {
this.compilationUnit = unit;
}
}