Java tutorial
/* * 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 groovy.beans; import org.codehaus.groovy.ast.ASTNode; import org.codehaus.groovy.ast.AnnotatedNode; import org.codehaus.groovy.ast.AnnotationNode; import org.codehaus.groovy.ast.ClassHelper; import org.codehaus.groovy.ast.ClassNode; import org.codehaus.groovy.ast.FieldNode; import org.codehaus.groovy.ast.MethodNode; import org.codehaus.groovy.ast.Parameter; import org.codehaus.groovy.ast.PropertyNode; import org.codehaus.groovy.ast.expr.Expression; import org.codehaus.groovy.ast.stmt.BlockStatement; import org.codehaus.groovy.ast.stmt.Statement; import org.codehaus.groovy.ast.tools.PropertyNodeUtils; import org.codehaus.groovy.control.CompilePhase; import org.codehaus.groovy.control.SourceUnit; import org.codehaus.groovy.control.messages.SimpleMessage; import org.codehaus.groovy.control.messages.SyntaxErrorMessage; import org.codehaus.groovy.syntax.SyntaxException; import org.codehaus.groovy.transform.GroovyASTTransformation; import org.objectweb.asm.Opcodes; import java.beans.PropertyVetoException; import java.beans.VetoableChangeListener; import java.beans.VetoableChangeSupport; import static org.apache.groovy.ast.tools.ClassNodeUtils.addGeneratedMethod; import static org.apache.groovy.util.BeanUtils.capitalize; import static org.codehaus.groovy.ast.tools.GeneralUtils.args; import static org.codehaus.groovy.ast.tools.GeneralUtils.assignS; import static org.codehaus.groovy.ast.tools.GeneralUtils.callThisX; import static org.codehaus.groovy.ast.tools.GeneralUtils.callX; import static org.codehaus.groovy.ast.tools.GeneralUtils.constX; import static org.codehaus.groovy.ast.tools.GeneralUtils.ctorX; import static org.codehaus.groovy.ast.tools.GeneralUtils.declS; import static org.codehaus.groovy.ast.tools.GeneralUtils.fieldX; import static org.codehaus.groovy.ast.tools.GeneralUtils.localVarX; import static org.codehaus.groovy.ast.tools.GeneralUtils.param; import static org.codehaus.groovy.ast.tools.GeneralUtils.params; import static org.codehaus.groovy.ast.tools.GeneralUtils.returnS; import static org.codehaus.groovy.ast.tools.GeneralUtils.stmt; import static org.codehaus.groovy.ast.tools.GeneralUtils.varX; /** * Handles generation of code for the {@code @Vetoable} annotation, and {@code @Bindable} * if also present. * <p> * Generally, it adds (if needed) a VetoableChangeSupport field and * the needed add/removeVetoableChangeListener methods to support the * listeners. * <p> * It also generates the setter and wires the setter through the * VetoableChangeSupport. * <p> * If a {@link Bindable} annotation is detected it also adds support similar * to what {@link BindableASTTransformation} would do. */ @GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION) public class VetoableASTTransformation extends BindableASTTransformation { protected static final ClassNode constrainedClassNode = ClassHelper.make(Vetoable.class); /** * Convenience method to see if an annotated node is {@code @Vetoable}. * * @param node the node to check * @return true if the node is constrained */ public static boolean hasVetoableAnnotation(AnnotatedNode node) { for (AnnotationNode annotation : node.getAnnotations()) { if (constrainedClassNode.equals(annotation.getClassNode())) { return true; } } return false; } /** * Handles the bulk of the processing, mostly delegating to other methods. * * @param nodes the AST nodes * @param source the source unit for the nodes */ public void visit(ASTNode[] nodes, SourceUnit source) { if (!(nodes[0] instanceof AnnotationNode) || !(nodes[1] instanceof AnnotatedNode)) { throw new RuntimeException("Internal error: wrong types: $node.class / $parent.class"); } AnnotationNode node = (AnnotationNode) nodes[0]; if (nodes[1] instanceof ClassNode) { addListenerToClass(source, (ClassNode) nodes[1]); } else { if ((((FieldNode) nodes[1]).getModifiers() & Opcodes.ACC_FINAL) != 0) { source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(new SyntaxException( "@groovy.beans.Vetoable cannot annotate a final property.", node.getLineNumber(), node.getColumnNumber(), node.getLastLineNumber(), node.getLastColumnNumber()), source)); } addListenerToProperty(source, node, (AnnotatedNode) nodes[1]); } } private void addListenerToProperty(SourceUnit source, AnnotationNode node, AnnotatedNode parent) { ClassNode declaringClass = parent.getDeclaringClass(); FieldNode field = ((FieldNode) parent); String fieldName = field.getName(); for (PropertyNode propertyNode : declaringClass.getProperties()) { boolean bindable = BindableASTTransformation.hasBindableAnnotation(parent) || BindableASTTransformation.hasBindableAnnotation(parent.getDeclaringClass()); if (propertyNode.getName().equals(fieldName)) { if (field.isStatic()) { //noinspection ThrowableInstanceNeverThrown source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(new SyntaxException( "@groovy.beans.Vetoable cannot annotate a static property.", node.getLineNumber(), node.getColumnNumber(), node.getLastLineNumber(), node.getLastColumnNumber()), source)); } else { createListenerSetter(source, bindable, declaringClass, propertyNode); } return; } } //noinspection ThrowableInstanceNeverThrown source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(new SyntaxException( "@groovy.beans.Vetoable must be on a property, not a field. Try removing the private, protected, or public modifier.", node.getLineNumber(), node.getColumnNumber(), node.getLastLineNumber(), node.getLastColumnNumber()), source)); } private void addListenerToClass(SourceUnit source, ClassNode classNode) { boolean bindable = BindableASTTransformation.hasBindableAnnotation(classNode); for (PropertyNode propertyNode : classNode.getProperties()) { if (!hasVetoableAnnotation(propertyNode.getField()) && !propertyNode.getField().isFinal() && !propertyNode.getField().isStatic()) { createListenerSetter(source, bindable || BindableASTTransformation.hasBindableAnnotation(propertyNode.getField()), classNode, propertyNode); } } } /** * Wrap an existing setter. */ private static void wrapSetterMethod(ClassNode classNode, boolean bindable, String propertyName) { String getterName = "get" + capitalize(propertyName); MethodNode setter = classNode.getSetterMethod("set" + capitalize(propertyName)); if (setter != null) { // Get the existing code block Statement code = setter.getCode(); Expression oldValue = localVarX("$oldValue"); Expression newValue = localVarX("$newValue"); Expression proposedValue = varX(setter.getParameters()[0].getName()); BlockStatement block = new BlockStatement(); // create a local variable to hold the old value from the getter block.addStatement(declS(oldValue, callThisX(getterName))); // add the fireVetoableChange method call block.addStatement( stmt(callThisX("fireVetoableChange", args(constX(propertyName), oldValue, proposedValue)))); // call the existing block, which will presumably set the value properly block.addStatement(code); if (bindable) { // get the new value to emit in the event block.addStatement(declS(newValue, callThisX(getterName))); // add the firePropertyChange method call block.addStatement( stmt(callThisX("firePropertyChange", args(constX(propertyName), oldValue, newValue)))); } // replace the existing code block with our new one setter.setCode(block); } } private void createListenerSetter(SourceUnit source, boolean bindable, ClassNode declaringClass, PropertyNode propertyNode) { if (bindable && needsPropertyChangeSupport(declaringClass, source)) { addPropertyChangeSupport(declaringClass); } if (needsVetoableChangeSupport(declaringClass, source)) { addVetoableChangeSupport(declaringClass); } String setterName = "set" + capitalize(propertyNode.getName()); if (declaringClass.getMethods(setterName).isEmpty()) { Expression fieldExpression = fieldX(propertyNode.getField()); BlockStatement setterBlock = new BlockStatement(); setterBlock.addStatement(createConstrainedStatement(propertyNode, fieldExpression)); if (bindable) { setterBlock.addStatement(createBindableStatement(propertyNode, fieldExpression)); } else { setterBlock.addStatement(createSetStatement(fieldExpression)); } // create method void <setter>(<type> fieldName) createSetterMethod(declaringClass, propertyNode, setterName, setterBlock); } else { wrapSetterMethod(declaringClass, bindable, propertyNode.getName()); } } /** * Creates a statement body similar to: * <code>this.fireVetoableChange("field", field, field = value)</code> * * @param propertyNode the field node for the property * @param fieldExpression a field expression for setting the property value * @return the created statement */ protected Statement createConstrainedStatement(PropertyNode propertyNode, Expression fieldExpression) { return stmt(callThisX("fireVetoableChange", args(constX(propertyNode.getName()), fieldExpression, varX("value")))); } /** * Creates a statement body similar to: * <code>field = value</code>. * <p> * Used when the field is not also {@code @Bindable}. * * @param fieldExpression a field expression for setting the property value * @return the created statement */ protected Statement createSetStatement(Expression fieldExpression) { return assignS(fieldExpression, varX("value")); } /** * Snoops through the declaring class and all parents looking for a field * of type VetoableChangeSupport. Remembers the field and returns false * if found otherwise returns true to indicate that such support should * be added. * * @param declaringClass the class to search * @return true if vetoable change support should be added */ protected boolean needsVetoableChangeSupport(ClassNode declaringClass, SourceUnit sourceUnit) { boolean foundAdd = false, foundRemove = false, foundFire = false; ClassNode consideredClass = declaringClass; while (consideredClass != null) { for (MethodNode method : consideredClass.getMethods()) { // just check length, MOP will match it up foundAdd = foundAdd || method.getName().equals("addVetoableChangeListener") && method.getParameters().length == 1; foundRemove = foundRemove || method.getName().equals("removeVetoableChangeListener") && method.getParameters().length == 1; foundFire = foundFire || method.getName().equals("fireVetoableChange") && method.getParameters().length == 3; if (foundAdd && foundRemove && foundFire) { return false; } } consideredClass = consideredClass.getSuperClass(); } // check if a super class has @Vetoable annotations consideredClass = declaringClass.getSuperClass(); while (consideredClass != null) { if (hasVetoableAnnotation(consideredClass)) return false; for (FieldNode field : consideredClass.getFields()) { if (hasVetoableAnnotation(field)) return false; } consideredClass = consideredClass.getSuperClass(); } if (foundAdd || foundRemove || foundFire) { sourceUnit.getErrorCollector().addErrorAndContinue(new SimpleMessage("@Vetoable cannot be processed on " + declaringClass.getName() + " because some but not all of addVetoableChangeListener, removeVetoableChange, and fireVetoableChange were declared in the current or super classes.", sourceUnit)); return false; } return true; } /** * Creates a setter method with the given body. * <p> * This differs from normal setters in that we need to add a declared * exception java.beans.PropertyVetoException * * @param declaringClass the class to which we will add the setter * @param propertyNode the field to back the setter * @param setterName the name of the setter * @param setterBlock the statement representing the setter block */ protected void createSetterMethod(ClassNode declaringClass, PropertyNode propertyNode, String setterName, Statement setterBlock) { ClassNode[] exceptions = { ClassHelper.make(PropertyVetoException.class) }; MethodNode setter = new MethodNode(setterName, PropertyNodeUtils.adjustPropertyModifiersForMethod(propertyNode), ClassHelper.VOID_TYPE, params(param(propertyNode.getType(), "value")), exceptions, setterBlock); setter.setSynthetic(true); // add it to the class addGeneratedMethod(declaringClass, setter); } /** * Adds the necessary field and methods to support vetoable change support. * <p> * Adds a new field: * <code>"protected final java.beans.VetoableChangeSupport this$vetoableChangeSupport = new java.beans.VetoableChangeSupport(this)"</code> * <p> * Also adds support methods: * <code>public void addVetoableChangeListener(java.beans.VetoableChangeListener)</code> * <code>public void addVetoableChangeListener(String, java.beans.VetoableChangeListener)</code> * <code>public void removeVetoableChangeListener(java.beans.VetoableChangeListener)</code> * <code>public void removeVetoableChangeListener(String, java.beans.VetoableChangeListener)</code> * <code>public java.beans.VetoableChangeListener[] getVetoableChangeListeners()</code> * * @param declaringClass the class to which we add the support field and methods */ protected void addVetoableChangeSupport(ClassNode declaringClass) { ClassNode vcsClassNode = ClassHelper.make(VetoableChangeSupport.class); ClassNode vclClassNode = ClassHelper.make(VetoableChangeListener.class); // add field: // protected static VetoableChangeSupport this$vetoableChangeSupport = new java.beans.VetoableChangeSupport(this) FieldNode vcsField = declaringClass.addField("this$vetoableChangeSupport", ACC_FINAL | ACC_PRIVATE | ACC_SYNTHETIC, vcsClassNode, ctorX(vcsClassNode, args(varX("this")))); // add method: // void addVetoableChangeListener(listener) { // this$vetoableChangeSupport.addVetoableChangeListener(listener) // } addGeneratedMethod(declaringClass, new MethodNode("addVetoableChangeListener", ACC_PUBLIC, ClassHelper.VOID_TYPE, params(param(vclClassNode, "listener")), ClassNode.EMPTY_ARRAY, stmt(callX(fieldX(vcsField), "addVetoableChangeListener", args(varX("listener", vclClassNode)))))); // add method: // void addVetoableChangeListener(name, listener) { // this$vetoableChangeSupport.addVetoableChangeListener(name, listener) // } addGeneratedMethod(declaringClass, new MethodNode("addVetoableChangeListener", ACC_PUBLIC, ClassHelper.VOID_TYPE, params(param(ClassHelper.STRING_TYPE, "name"), param(vclClassNode, "listener")), ClassNode.EMPTY_ARRAY, stmt(callX(fieldX(vcsField), "addVetoableChangeListener", args(varX("name", ClassHelper.STRING_TYPE), varX("listener", vclClassNode)))))); // add method: // boolean removeVetoableChangeListener(listener) { // return this$vetoableChangeSupport.removeVetoableChangeListener(listener); // } addGeneratedMethod(declaringClass, new MethodNode("removeVetoableChangeListener", ACC_PUBLIC, ClassHelper.VOID_TYPE, params(param(vclClassNode, "listener")), ClassNode.EMPTY_ARRAY, stmt(callX(fieldX(vcsField), "removeVetoableChangeListener", args(varX("listener", vclClassNode)))))); // add method: void removeVetoableChangeListener(name, listener) addGeneratedMethod(declaringClass, new MethodNode("removeVetoableChangeListener", ACC_PUBLIC, ClassHelper.VOID_TYPE, params(param(ClassHelper.STRING_TYPE, "name"), param(vclClassNode, "listener")), ClassNode.EMPTY_ARRAY, stmt(callX(fieldX(vcsField), "removeVetoableChangeListener", args(varX("name", ClassHelper.STRING_TYPE), varX("listener", vclClassNode)))))); // add method: // void fireVetoableChange(String name, Object oldValue, Object newValue) // throws PropertyVetoException // { // this$vetoableChangeSupport.fireVetoableChange(name, oldValue, newValue) // } addGeneratedMethod(declaringClass, new MethodNode("fireVetoableChange", ACC_PUBLIC, ClassHelper.VOID_TYPE, params(param(ClassHelper.STRING_TYPE, "name"), param(ClassHelper.OBJECT_TYPE, "oldValue"), param(ClassHelper.OBJECT_TYPE, "newValue")), new ClassNode[] { ClassHelper.make(PropertyVetoException.class) }, stmt(callX(fieldX(vcsField), "fireVetoableChange", args(varX("name", ClassHelper.STRING_TYPE), varX("oldValue"), varX("newValue")))))); // add method: // VetoableChangeListener[] getVetoableChangeListeners() { // return this$vetoableChangeSupport.getVetoableChangeListeners // } addGeneratedMethod(declaringClass, new MethodNode("getVetoableChangeListeners", ACC_PUBLIC, vclClassNode.makeArray(), Parameter.EMPTY_ARRAY, ClassNode.EMPTY_ARRAY, returnS(callX(fieldX(vcsField), "getVetoableChangeListeners")))); // add method: // VetoableChangeListener[] getVetoableChangeListeners(String name) { // return this$vetoableChangeSupport.getVetoableChangeListeners(name) // } addGeneratedMethod(declaringClass, new MethodNode("getVetoableChangeListeners", ACC_PUBLIC, vclClassNode.makeArray(), params(param(ClassHelper.STRING_TYPE, "name")), ClassNode.EMPTY_ARRAY, returnS(callX(fieldX(vcsField), "getVetoableChangeListeners", args(varX("name", ClassHelper.STRING_TYPE)))))); } }