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Groovy example source code file (PackageScopeASTTransformation.java)

This example Groovy source code file (PackageScopeASTTransformation.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

annotatednode, annotationnode, expression, list, list, listexpression, my_type_name, my_type_name, propertynode, runtimeexception, runtimeexception, string, string, target_class_name, util

The Groovy PackageScopeASTTransformation.java source code

/*
 * Copyright 2008-2010 the original author or authors.
 *
 * 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.codehaus.groovy.transform;

import groovy.transform.PackageScope;
import groovy.transform.PackageScopeTarget;
import org.codehaus.groovy.ast.*;
import org.codehaus.groovy.ast.expr.ClassExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.ListExpression;
import org.codehaus.groovy.ast.expr.PropertyExpression;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.objectweb.asm.Opcodes;

import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;

/**
 * Handles transformation for the @PackageScope annotation.
 * <p>
 * Both the deprecated groovy.lang.PackageScope and groovy.transform.PackageScope
 * annotations are supported. The former will be removed in a future version of Groovy.
 *
 * @author Paul King
 */
@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
public class PackageScopeASTTransformation implements ASTTransformation, Opcodes {

    private static final Class MY_CLASS = PackageScope.class;
    private static final ClassNode MY_TYPE = ClassHelper.make(MY_CLASS);
    private static final String MY_TYPE_NAME = "@" + MY_TYPE.getNameWithoutPackage();
    private static final String LEGACY_TYPE_NAME = "groovy.lang.PackageScope";
    private static final Class TARGET_CLASS = groovy.transform.PackageScopeTarget.class;
    private static final String TARGET_CLASS_NAME = ClassHelper.make(TARGET_CLASS).getNameWithoutPackage();

    public void visit(ASTNode[] nodes, SourceUnit source) {
        if (nodes.length != 2 || !(nodes[0] instanceof AnnotationNode) || !(nodes[1] instanceof AnnotatedNode)) {
            throw new RuntimeException("Internal error: expecting [AnnotationNode, AnnotatedNode] but got: " + Arrays.asList(nodes));
        }

        AnnotatedNode parent = (AnnotatedNode) nodes[1];
        AnnotationNode node = (AnnotationNode) nodes[0];
        boolean legacyMode = LEGACY_TYPE_NAME.equals(node.getClassNode().getName());
        if (!MY_TYPE.equals(node.getClassNode()) && !legacyMode) return;

        Expression value = node.getMember("value");
        if (parent instanceof ClassNode) {
            List<groovy.transform.PackageScopeTarget> targets;
            if (value == null) targets = Arrays.asList(legacyMode ? PackageScopeTarget.FIELDS: PackageScopeTarget.CLASS);
            else targets = determineTargets(value);
            visitClassNode((ClassNode) parent, targets);
            parent.getAnnotations();
        } else {
            if (value != null)
                throw new RuntimeException("Error during " + MY_TYPE_NAME
                            + " processing: " + TARGET_CLASS_NAME + " only allowed at class level.");
            if (parent instanceof MethodNode) {
                visitMethodNode((MethodNode) parent);
            } else if (parent instanceof FieldNode) {
                visitFieldNode((FieldNode) parent);
            }
        }
    }

    private void visitMethodNode(MethodNode methodNode) {
        if (methodNode.isSyntheticPublic()) revertVisibility(methodNode);
        else throw new RuntimeException("Can't use " + MY_TYPE_NAME + " for method '" + methodNode.getName() + "' which has explicit visibility.");
    }

    private void visitClassNode(ClassNode cNode, List<PackageScopeTarget> value) {
        String cName = cNode.getName();
        if (cNode.isInterface() && value.size() != 1 && value.get(0) != PackageScopeTarget.CLASS) {
            throw new RuntimeException("Error processing interface '" + cName + "'. " + MY_TYPE_NAME + " not allowed for interfaces except when targeting Class level.");
        }
        if (value.contains(groovy.transform.PackageScopeTarget.CLASS)) {
            if (cNode.isSyntheticPublic()) revertVisibility(cNode);
            else throw new RuntimeException("Can't use " + MY_TYPE_NAME + " for class '" + cNode.getName() + "' which has explicit visibility.");
        }
        if (value.contains(groovy.transform.PackageScopeTarget.METHODS)) {
            final List<MethodNode> mList = cNode.getMethods();
            for (MethodNode mNode : mList) {
                if (mNode.isSyntheticPublic()) revertVisibility(mNode);
            }
        }
        if (value.contains(PackageScopeTarget.FIELDS)) {
            final List<PropertyNode> pList = cNode.getProperties();
            List<PropertyNode> foundProps = new ArrayList();
            List<String> foundNames = new ArrayList();
            for (PropertyNode pNode : pList) {
                foundProps.add(pNode);
                foundNames.add(pNode.getName());
            }
            for (PropertyNode pNode : foundProps) {
                pList.remove(pNode);
            }
            final List<FieldNode> fList = cNode.getFields();
            for (FieldNode fNode : fList) {
                if (foundNames.contains(fNode.getName())) {
                    revertVisibility(fNode);
                }
            }
        }
    }

    private void visitFieldNode(FieldNode fNode) {
        final ClassNode cNode = fNode.getDeclaringClass();
        final List<PropertyNode> pList = cNode.getProperties();
        PropertyNode foundProp = null;
        for (PropertyNode pNode : pList) {
            if (pNode.getName().equals(fNode.getName())) {
                foundProp = pNode;
                break;
            }
        }
        if (foundProp != null) {
            revertVisibility(fNode);
            pList.remove(foundProp);
        }
    }

    private void revertVisibility(FieldNode fNode) {
        fNode.setModifiers(fNode.getModifiers() & ~ACC_PRIVATE);
    }

    private void revertVisibility(MethodNode mNode) {
        mNode.setModifiers(mNode.getModifiers() & ~ACC_PUBLIC);
    }

    private void revertVisibility(ClassNode cNode) {
        cNode.setModifiers(cNode.getModifiers() & ~ACC_PUBLIC);
    }

    private List<groovy.transform.PackageScopeTarget> determineTargets(Expression expr) {
        List<groovy.transform.PackageScopeTarget> list = new ArrayList();
        if (expr instanceof PropertyExpression) {
            list.add(extractTarget((PropertyExpression) expr));
        } else if (expr instanceof ListExpression) {
            final ListExpression expressionList = (ListExpression) expr;
            final List<Expression> expressions = expressionList.getExpressions();
            for (Expression ex : expressions) {
                if (ex instanceof PropertyExpression) {
                    list.add(extractTarget((PropertyExpression) ex));
                }
            }
        }
        return list;
    }

    private groovy.transform.PackageScopeTarget extractTarget(PropertyExpression expr) {
        Expression oe = expr.getObjectExpression();
        if (oe instanceof ClassExpression) {
            ClassExpression ce = (ClassExpression) oe;
            if (ce.getType().getName().equals("groovy.transform.PackageScopeTarget")) {
                Expression prop = expr.getProperty();
                if (prop instanceof ConstantExpression) {
                    String propName = (String) ((ConstantExpression) prop).getValue();
                    try {
                        return PackageScopeTarget.valueOf(propName);
                    } catch(IllegalArgumentException iae) {
                        /* ignore */
                    }
                }
            }
        }
        throw new RuntimeException("Internal error during " + MY_TYPE_NAME
                + " processing. Annotation parameters must be of type: " + TARGET_CLASS_NAME + ".");
    }

}

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