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Groovy example source code file (Java5.java)

This example Groovy source code file (Java5.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

annotation, annotation, class, class, classnode, classnode, expression, genericstype, genericstype, listexpression, method, parameter, propertyexpression, reflection, type, type, util

The Groovy Java5.java source code

/*
 * Copyright 2003-2011 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.vmplugin.v5;

import org.codehaus.groovy.GroovyBugError;
import org.codehaus.groovy.ast.*;
import org.codehaus.groovy.ast.expr.*;
import org.codehaus.groovy.ast.stmt.ReturnStatement;
import org.codehaus.groovy.vmplugin.VMPlugin;

import java.lang.annotation.*;
import java.lang.reflect.*;
import java.util.List;

/**
 * java 5 based functions
 *
 * @author Jochen Theodorou
 */
public class Java5 implements VMPlugin {
    private static Class[] EMPTY_CLASS_ARRAY = new Class[0];
    private static final Class[] PLUGIN_DGM = {PluginDefaultGroovyMethods.class};

    public void setAdditionalClassInformation(ClassNode cn) {
        setGenericsTypes(cn);
    }

    private void setGenericsTypes(ClassNode cn) {
        TypeVariable[] tvs = cn.getTypeClass().getTypeParameters();
        GenericsType[] gts = configureTypeVariable(tvs);
        cn.setGenericsTypes(gts);
    }

    private GenericsType[] configureTypeVariable(TypeVariable[] tvs) {
        if (tvs.length == 0) return null;
        GenericsType[] gts = new GenericsType[tvs.length];
        for (int i = 0; i < tvs.length; i++) {
            gts[i] = configureTypeVariableDefinition(tvs[i]);
        }
        return gts;
    }

    private GenericsType configureTypeVariableDefinition(TypeVariable tv) {
        ClassNode base = configureTypeVariableReference(tv);
        ClassNode redirect = base.redirect();
        base.setRedirect(null);
        Type[] tBounds = tv.getBounds();
        GenericsType gt;
        if (tBounds.length == 0) {
            gt = new GenericsType(base);
        } else {
            ClassNode[] cBounds = configureTypes(tBounds);
            gt = new GenericsType(base, cBounds, null);
            gt.setName(base.getName());
            gt.setPlaceholder(true);
        }
        base.setRedirect(redirect);
        return gt;
    }

    private ClassNode[] configureTypes(Type[] types) {
        if (types.length == 0) return null;
        ClassNode[] nodes = new ClassNode[types.length];
        for (int i = 0; i < types.length; i++) {
            nodes[i] = configureType(types[i]);
        }
        return nodes;
    }

    private ClassNode configureType(Type type) {
        if (type instanceof WildcardType) {
            return configureWildcardType((WildcardType) type);
        } else if (type instanceof ParameterizedType) {
            return configureParameterizedType((ParameterizedType) type);
        } else if (type instanceof GenericArrayType) {
            return configureGenericArray((GenericArrayType) type);
        } else if (type instanceof TypeVariable) {
            return configureTypeVariableReference((TypeVariable) type);
        } else if (type instanceof Class) {
            return configureClass((Class) type);
        } else if (type==null) {
            throw new GroovyBugError("Type is null. Most probably you let a transform reuse existing ClassNodes with generics information, that is now used in a wrong context.");
        } else {
            throw new GroovyBugError("unknown type: " + type + " := " + type.getClass());
        }
    }

    private ClassNode configureClass(Class c) {
        if (c.isPrimitive()) {
            return ClassHelper.make(c);
        } else {
            return ClassHelper.makeWithoutCaching(c, false);
        }
    }

    private ClassNode configureGenericArray(GenericArrayType genericArrayType) {
        Type component = genericArrayType.getGenericComponentType();
        ClassNode node = configureType(component);
        return node.makeArray();
    }

    private ClassNode configureWildcardType(WildcardType wildcardType) {
        ClassNode base = ClassHelper.makeWithoutCaching("?");
        base.setRedirect(ClassHelper.OBJECT_TYPE);
        //TODO: more than one lower bound for wildcards?
        ClassNode[] lowers = configureTypes(wildcardType.getLowerBounds());
        ClassNode lower = null;
        // TODO: is it safe to remove this? What was the original intention?
        if (lower != null) lower = lowers[0];

        ClassNode[] upper = configureTypes(wildcardType.getUpperBounds());
        GenericsType t = new GenericsType(base, upper, lower);
        t.setWildcard(true);

        ClassNode ref = ClassHelper.makeWithoutCaching(Object.class, false);
        ref.setGenericsTypes(new GenericsType[]{t});

        return ref;
    }

    private ClassNode configureParameterizedType(ParameterizedType parameterizedType) {
        ClassNode base = configureType(parameterizedType.getRawType());
        GenericsType[] gts = configureTypeArguments(parameterizedType.getActualTypeArguments());
        base.setGenericsTypes(gts);
        return base;
    }

    private ClassNode configureTypeVariableReference(TypeVariable tv) {
        ClassNode cn = ClassHelper.makeWithoutCaching(tv.getName());
        cn.setGenericsPlaceHolder(true);
        ClassNode cn2 = ClassHelper.makeWithoutCaching(tv.getName());
        cn2.setGenericsPlaceHolder(true);
        GenericsType[] gts = new GenericsType[]{new GenericsType(cn2)};
        cn.setGenericsTypes(gts);
        cn.setRedirect(ClassHelper.OBJECT_TYPE);
        return cn;
    }

    private GenericsType[] configureTypeArguments(Type[] ta) {
        if (ta.length == 0) return null;
        GenericsType[] gts = new GenericsType[ta.length];
        for (int i = 0; i < ta.length; i++) {
            ClassNode t = configureType(ta[i]);
            if (ta[i] instanceof WildcardType) {
                GenericsType[] gen = t.getGenericsTypes();
                gts[i] = gen[0];
            } else {
                gts[i] = new GenericsType(t);
            }
        }
        return gts;
    }

    public Class[] getPluginDefaultGroovyMethods() {
        return PLUGIN_DGM;
    }

    public Class[] getPluginStaticGroovyMethods() {
        return EMPTY_CLASS_ARRAY;
    }

    private void setAnnotationMetaData(Annotation[] annotations, AnnotatedNode an) {
        for (Annotation annotation : annotations) {
            AnnotationNode node = new AnnotationNode(ClassHelper.make(annotation.annotationType()));
            configureAnnotation(node, annotation);
            an.addAnnotation(node);
        }
    }

    private void configureAnnotationFromDefinition(AnnotationNode definition, AnnotationNode root) {
        ClassNode type = definition.getClassNode();
        if (!type.isResolved()) return;
        Class clazz = type.getTypeClass();
        if (clazz == Retention.class) {
            Expression exp = definition.getMember("value");
            if (!(exp instanceof PropertyExpression)) return;
            PropertyExpression pe = (PropertyExpression) exp;
            String name = pe.getPropertyAsString();
            RetentionPolicy policy = RetentionPolicy.valueOf(name);
            setRetentionPolicy(policy, root);
        } else if (clazz == Target.class) {
            Expression exp = definition.getMember("value");
            if (!(exp instanceof ListExpression)) return;
            ListExpression le = (ListExpression) exp;
            int bitmap = 0;
            for (Expression e : le.getExpressions()) {
                PropertyExpression element = (PropertyExpression) e;
                String name = element.getPropertyAsString();
                ElementType value = ElementType.valueOf(name);
                bitmap |= getElementCode(value);
            }
            root.setAllowedTargets(bitmap);
        }
    }

    public void configureAnnotation(AnnotationNode node) {
        ClassNode type = node.getClassNode();
        List<AnnotationNode> annotations = type.getAnnotations();
        for (AnnotationNode an : annotations) {
            configureAnnotationFromDefinition(an, node);
        }
        configureAnnotationFromDefinition(node, node);
    }

    private void configureAnnotation(AnnotationNode node, Annotation annotation) {
        Class type = annotation.annotationType();
        if (type == Retention.class) {
            Retention r = (Retention) annotation;
            RetentionPolicy value = r.value();
            setRetentionPolicy(value, node);
            node.setMember("value", new PropertyExpression(
                    new ClassExpression(ClassHelper.makeWithoutCaching(RetentionPolicy.class, false)),
                    value.toString()));
        } else if (type == Target.class) {
            Target t = (Target) annotation;
            ElementType[] elements = t.value();
            ListExpression elementExprs = new ListExpression();
            for (ElementType element : elements) {
                elementExprs.addExpression(new PropertyExpression(
                        new ClassExpression(ClassHelper.ELEMENT_TYPE_TYPE), element.name()));
            }
            node.setMember("value", elementExprs);
        }
        else {
            Method[] declaredMethods = type.getDeclaredMethods();
            for (Method declaredMethod : declaredMethods) {
                try {
                    Object value = declaredMethod.invoke(annotation);
                    Expression valueExpression = annotationValueToExpression(value);
                    if (valueExpression == null)
                        continue;
                    node.setMember(declaredMethod.getName(), valueExpression);
                } catch (IllegalAccessException e) {
                } catch (InvocationTargetException e) {
                }
            }
        }
    }

    private Expression annotationValueToExpression (Object value) {
        if (value == null || value instanceof String || value instanceof Number || value instanceof Character || value instanceof Boolean)
            return new ConstantExpression(value);

        if (value instanceof Class)
            return new ClassExpression(ClassHelper.makeWithoutCaching((Class)value));

        if (value.getClass().isArray()) {
            ListExpression elementExprs = new ListExpression();
            int len = Array.getLength(value);
            for (int i = 0; i != len; ++i)
                elementExprs.addExpression(annotationValueToExpression(Array.get(value, i)));
            return elementExprs;
        }

        return null;
    }

    private void setRetentionPolicy(RetentionPolicy value, AnnotationNode node) {
        switch (value) {
            case RUNTIME:
                node.setRuntimeRetention(true);
                break;
            case SOURCE:
                node.setSourceRetention(true);
                break;
            case CLASS:
                node.setClassRetention(true);
                break;
            default:
                throw new GroovyBugError("unsupported Retention " + value);
        }
    }

    private int getElementCode(ElementType value) {
        switch (value) {
            case TYPE:
                return AnnotationNode.TYPE_TARGET;
            case CONSTRUCTOR:
                return AnnotationNode.CONSTRUCTOR_TARGET;
            case METHOD:
                return AnnotationNode.METHOD_TARGET;
            case FIELD:
                return AnnotationNode.FIELD_TARGET;
            case PARAMETER:
                return AnnotationNode.PARAMETER_TARGET;
            case LOCAL_VARIABLE:
                return AnnotationNode.LOCAL_VARIABLE_TARGET;
            case ANNOTATION_TYPE:
                return AnnotationNode.ANNOTATION_TARGET;
            case PACKAGE:
                return AnnotationNode.PACKAGE_TARGET;
            default:
                throw new GroovyBugError("unsupported Target " + value);
        }
    }

    private void setMethodDefaultValue(MethodNode mn, Method m) {
        Object defaultValue = m.getDefaultValue();
        ConstantExpression cExp = ConstantExpression.NULL;
        if (defaultValue!=null) cExp = new ConstantExpression(defaultValue);
        mn.setCode(new ReturnStatement(cExp));
        mn.setAnnotationDefault(true);
    }

    public void configureClassNode(CompileUnit compileUnit, ClassNode classNode) {
        Class clazz = classNode.getTypeClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field f : fields) {
            ClassNode ret = makeClassNode(compileUnit, f.getGenericType(), f.getType());
            FieldNode fn = new FieldNode(f.getName(), f.getModifiers(), ret, classNode, null);
            setAnnotationMetaData(f.getAnnotations(), fn);
            classNode.addField(fn);
        }
        Method[] methods = clazz.getDeclaredMethods();
        for (Method m : methods) {
            ClassNode ret = makeClassNode(compileUnit, m.getGenericReturnType(), m.getReturnType());
            Parameter[] params = makeParameters(compileUnit, m.getGenericParameterTypes(), m.getParameterTypes(), m.getParameterAnnotations());
            ClassNode[] exceptions = makeClassNodes(compileUnit, m.getGenericExceptionTypes(), m.getExceptionTypes());
            MethodNode mn = new MethodNode(m.getName(), m.getModifiers(), ret, params, exceptions, null);
            setMethodDefaultValue(mn, m);
            setAnnotationMetaData(m.getAnnotations(), mn);
            mn.setGenericsTypes(configureTypeVariable(m.getTypeParameters()));
            classNode.addMethod(mn);
        }
        Constructor[] constructors = clazz.getDeclaredConstructors();
        for (Constructor ctor : constructors) {
            Parameter[] params = makeParameters(compileUnit, ctor.getGenericParameterTypes(), ctor.getParameterTypes(), ctor.getParameterAnnotations());
            ClassNode[] exceptions = makeClassNodes(compileUnit, ctor.getGenericExceptionTypes(), ctor.getExceptionTypes());
            classNode.addConstructor(ctor.getModifiers(), params, exceptions, null);
        }

        Class sc = clazz.getSuperclass();
        if (sc != null) classNode.setUnresolvedSuperClass(makeClassNode(compileUnit, clazz.getGenericSuperclass(), sc));
        makeInterfaceTypes(compileUnit, classNode, clazz);
        setAnnotationMetaData(classNode.getTypeClass().getAnnotations(), classNode);

        PackageNode packageNode = classNode.getPackage();
        if (packageNode != null) {
            setAnnotationMetaData(classNode.getTypeClass().getPackage().getAnnotations(), packageNode);
        }
    }

    private void makeInterfaceTypes(CompileUnit cu, ClassNode classNode, Class clazz) {
        Type[] interfaceTypes = clazz.getGenericInterfaces();
        if (interfaceTypes.length == 0) {
            classNode.setInterfaces(ClassNode.EMPTY_ARRAY);
        } else {
            Class[] interfaceClasses = clazz.getInterfaces();
            ClassNode[] ret = new ClassNode[interfaceTypes.length];
            for (int i = 0; i < interfaceTypes.length; i++) {
                ret[i] = makeClassNode(cu, interfaceTypes[i], interfaceClasses[i]);
            }
            classNode.setInterfaces(ret);
        }
    }

    private ClassNode[] makeClassNodes(CompileUnit cu, Type[] types, Class[] cls) {
        ClassNode[] nodes = new ClassNode[types.length];
        for (int i = 0; i < nodes.length; i++) {
            nodes[i] = makeClassNode(cu, types[i], cls[i]);
        }
        return nodes;
    }

    private ClassNode makeClassNode(CompileUnit cu, Type t, Class c) {
        ClassNode back = null;
        if (cu != null) back = cu.getClass(c.getName());
        if (back == null) back = ClassHelper.make(c);
        if (!(t instanceof Class)) {
            ClassNode front = configureType(t);
            front.setRedirect(back);
            return front;
        }
        return back;
    }

    private Parameter[] makeParameters(CompileUnit cu, Type[] types, Class[] cls, Annotation[][] parameterAnnotations) {
        Parameter[] params = Parameter.EMPTY_ARRAY;
        if (types.length > 0) {
            params = new Parameter[types.length];
            for (int i = 0; i < params.length; i++) {
                params[i] = makeParameter(cu, types[i], cls[i], parameterAnnotations[i], i);
            }
        }
        return params;
    }

    private Parameter makeParameter(CompileUnit cu, Type type, Class cl, Annotation[] annotations, int idx) {
        ClassNode cn = makeClassNode(cu, type, cl);
        Parameter parameter = new Parameter(cn, "param" + idx);
        setAnnotationMetaData(annotations, parameter);
        return parameter;
    }
}

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