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Groovy example source code file (StaticImportVisitor.java)

This example Groovy source code file (StaticImportVisitor.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

classexpression, classnode, constantexpression, constantexpression, expression, expression, importnode, importnode, listexpression, map, propertyexpression, staticmethodcallexpression, string, string, util

The Groovy StaticImportVisitor.java source code

/*
 * Copyright 2003-2010 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.control;

import static org.codehaus.groovy.runtime.MetaClassHelper.capitalize;

import org.codehaus.groovy.ast.*;
import org.codehaus.groovy.ast.expr.*;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.syntax.Types;

import java.util.*;

/**
 * Visitor to resolve constants and method calls from static Imports
 *
 * @author Jochen Theodorou
 * @author Paul King
 */
public class StaticImportVisitor extends ClassCodeExpressionTransformer {
    private ClassNode currentClass;
    private MethodNode currentMethod;
    private SourceUnit source;
    private boolean inSpecialConstructorCall;
    private boolean inClosure;
    private boolean inPropertyExpression;
    private Expression foundConstant;
    private Expression foundArgs;
    private boolean inAnnotation;
    private boolean inLeftExpression;

    public void visitClass(ClassNode node, SourceUnit source) {
        this.currentClass = node;
        this.source = source;
        super.visitClass(node);
    }

    @Override
    protected void visitConstructorOrMethod(MethodNode node, boolean isConstructor) {
        this.currentMethod = node;
        super.visitConstructorOrMethod(node, isConstructor);
        this.currentMethod = null;
    }

    @Override
    public void visitAnnotations(AnnotatedNode node) {
        boolean oldInAnnotation = inAnnotation;
        inAnnotation = true;
        super.visitAnnotations(node);
        inAnnotation = oldInAnnotation;
    }

    public Expression transform(Expression exp) {
        if (exp == null) return null;
        if (exp.getClass() == VariableExpression.class) {
            return transformVariableExpression((VariableExpression) exp);
        }
        if (exp.getClass() == BinaryExpression.class) {
            return transformBinaryExpression((BinaryExpression) exp);
        }
        if (exp.getClass() == PropertyExpression.class) {
            return transformPropertyExpression((PropertyExpression) exp);
        }
        if (exp.getClass() == MethodCallExpression.class) {
            return transformMethodCallExpression((MethodCallExpression) exp);
        }
        if (exp.getClass() == ClosureExpression.class) {
            return transformClosureExpression((ClosureExpression) exp);
        }
        if (exp.getClass() == ConstructorCallExpression.class) {
            return transformConstructorCallExpression((ConstructorCallExpression) exp);
        }
        if (exp.getClass() == ArgumentListExpression.class) {
            Expression result = exp.transformExpression(this);
            if (inPropertyExpression) {
                foundArgs = result;
            }
            return result;
        }
        if (exp instanceof ConstantExpression) {
            Expression result = exp.transformExpression(this);
            if (inPropertyExpression) {
                foundConstant = result;
            }
            if (inAnnotation && exp instanceof AnnotationConstantExpression) {
                ConstantExpression ce = (ConstantExpression) result;
                if (ce.getValue() instanceof AnnotationNode) {
                    // replicate a little bit of AnnotationVisitor here
                    // because we can't wait until later to do this
                    AnnotationNode an = (AnnotationNode) ce.getValue();
                    Map<String, Expression> attributes = an.getMembers();
                    for (Map.Entry<String, Expression> entry : attributes.entrySet()) {
                        Expression attrExpr = transform(entry.getValue());
                        entry.setValue(attrExpr);
                    }

                }
            }
            return result;
        }
        return exp.transformExpression(this);
    }

    // if you have a Bar class with a static foo property, and this:
    //   import static Bar.foo as baz
    // then this constructor (not normal usage of statics):
    //   new Bar(baz:1)
    // will become:
    //   new Bar(foo:1)

    private Expression transformMapEntryExpression(MapEntryExpression me, ClassNode constructorCallType) {
        Expression key = me.getKeyExpression();
        Expression value = me.getValueExpression();
        ModuleNode module = currentClass.getModule();
        if (module != null && key instanceof ConstantExpression) {
            Map<String, ImportNode> importNodes = module.getStaticImports();
            if (importNodes.containsKey(key.getText())) {
                ImportNode importNode = importNodes.get(key.getText());
                if (importNode.getType().equals(constructorCallType)) {
                    String newKey = importNode.getFieldName();
                    return new MapEntryExpression(new ConstantExpression(newKey), value.transformExpression(this));
                }
            }
        }
        return me;
    }

    protected Expression transformBinaryExpression(BinaryExpression be) {
        int type = be.getOperation().getType();
        boolean oldInLeftExpression;
        Expression right = transform(be.getRightExpression());
        be.setRightExpression(right);
        Expression left;
        if (type == Types.EQUAL) {
            oldInLeftExpression = inLeftExpression;
            inLeftExpression = true;
            left = transform(be.getLeftExpression());
            inLeftExpression = oldInLeftExpression;
            if (left instanceof StaticMethodCallExpression) {
                StaticMethodCallExpression smce = (StaticMethodCallExpression) left;
                StaticMethodCallExpression result = new StaticMethodCallExpression(smce.getOwnerType(), smce.getMethod(), right);
                setSourcePosition(result, be);
                return result;
            }
        } else {
            left = transform(be.getLeftExpression());            
        }
        be.setLeftExpression(left);
        return be;
    }

    protected Expression transformVariableExpression(VariableExpression ve) {
        Variable v = ve.getAccessedVariable();
        if (v != null && v instanceof DynamicVariable) {
            Expression result = findStaticFieldOrPropAccessorImportFromModule(v.getName());
            if (result != null) {
                setSourcePosition(result, ve);
                if (inAnnotation) {
                    result = transformInlineConstants(result);
                }
                return result;
            }
        }
        return ve;
    }

    /**
     * Set the source position of toSet including its property expression if it has one.
     *
     * @param toSet resulting node
     * @param origNode original node
     */
    private void setSourcePosition(Expression toSet, Expression origNode) {
        toSet.setSourcePosition(origNode);
        if (toSet instanceof PropertyExpression) {
            ((PropertyExpression) toSet).getProperty().setSourcePosition(origNode);
        }
    }

    // resolve constant-looking expressions statically (do here as gets transformed away later)

    private Expression transformInlineConstants(Expression exp) {
        if (exp instanceof PropertyExpression) {
            PropertyExpression pe = (PropertyExpression) exp;
            if (pe.getObjectExpression() instanceof ClassExpression) {
                ClassExpression ce = (ClassExpression) pe.getObjectExpression();
                ClassNode type = ce.getType();
                if (type.isEnum()) return exp;
                Expression constant = findConstant(type.getField(pe.getPropertyAsString()));
                if (constant != null) return constant;
            }
        } else if (exp instanceof ListExpression) {
            ListExpression le = (ListExpression) exp;
            ListExpression result = new ListExpression();
            for (Expression e : le.getExpressions()) {
                result.addExpression(transformInlineConstants(e));
            }
            return result;
        }

        return exp;
    }

    private Expression findConstant(FieldNode fn) {
        if (fn != null && !fn.isEnum() && fn.isStatic() && fn.isFinal()) {
            if (fn.getInitialValueExpression() instanceof ConstantExpression) {
                return fn.getInitialValueExpression();
            }
        }
        return null;
    }

    protected Expression transformMethodCallExpression(MethodCallExpression mce) {
        Expression args = transform(mce.getArguments());
        Expression method = transform(mce.getMethod());
        Expression object = transform(mce.getObjectExpression());
        boolean isExplicitThisOrSuper = false;
        if (object instanceof VariableExpression) {
            VariableExpression ve = (VariableExpression) object;
            isExplicitThisOrSuper = !mce.isImplicitThis() && (ve.getName().equals("this") || ve.getName().equals("super"));
        }

        if (mce.isImplicitThis() || isExplicitThisOrSuper) {
            if (mce.isImplicitThis()) {
                Expression ret = findStaticMethodImportFromModule(method, args);
                if (ret != null) {
                    setSourcePosition(ret, mce);
                    return ret;
                }
                if (method instanceof ConstantExpression && !inLeftExpression) {
                    // could be a closure field
                    String methodName = (String) ((ConstantExpression) method).getValue();
                    ret = findStaticFieldOrPropAccessorImportFromModule(methodName);
                    if (ret != null) {
                        ret = new MethodCallExpression(ret, "call", args);
                        setSourcePosition(ret, mce);
                        return ret;
                    }
                }
            }

            if (method instanceof ConstantExpression) {
                ConstantExpression ce = (ConstantExpression) method;
                Object value = ce.getValue();
                if (value instanceof String) {
                    String methodName = (String) value;
                    boolean lookForPossibleStaticMethod = !methodName.equals("call");
                    if (currentMethod != null && !currentMethod.isStatic()) {
                        if (currentClass.hasPossibleMethod(methodName, args)) {
                            lookForPossibleStaticMethod = false;
                        }
                    }
                    if (inSpecialConstructorCall ||
                            (lookForPossibleStaticMethod && currentClass.hasPossibleStaticMethod(methodName, args))) {
                        StaticMethodCallExpression smce = new StaticMethodCallExpression(currentClass, methodName, args);
                    	setSourcePosition(smce, mce);
                        return smce;
                    }
                }
            }
        }

        MethodCallExpression result = new MethodCallExpression(object, method, args);
        result.setSafe(mce.isSafe());
        result.setImplicitThis(mce.isImplicitThis());
        result.setSpreadSafe(mce.isSpreadSafe());
        result.setMethodTarget(mce.getMethodTarget());
        setSourcePosition(result, mce);
        return result;
    }

    protected Expression transformConstructorCallExpression(ConstructorCallExpression cce) {
        inSpecialConstructorCall = cce.isSpecialCall();
        Expression expression = cce.getArguments();
        if (expression instanceof TupleExpression) {
            TupleExpression tuple = (TupleExpression) expression;
            if (tuple.getExpressions().size() == 1) {
                expression = tuple.getExpression(0);
                if (expression instanceof NamedArgumentListExpression) {
                    NamedArgumentListExpression namedArgs = (NamedArgumentListExpression) expression;
                    List<MapEntryExpression> entryExpressions = namedArgs.getMapEntryExpressions();
                    for (int i = 0; i < entryExpressions.size(); i++) {
                        entryExpressions.set(i, (MapEntryExpression) transformMapEntryExpression(entryExpressions.get(i), cce.getType()));
                    }
                }
            }
        }
        Expression ret = cce.transformExpression(this);
        inSpecialConstructorCall = false;
        return ret;
    }

    protected Expression transformClosureExpression(ClosureExpression ce) {
        boolean oldInClosure = inClosure;
        inClosure = true;
        Statement code = ce.getCode();
        if (code != null) code.visit(this);
        inClosure = oldInClosure;
        return ce;
    }

    protected Expression transformPropertyExpression(PropertyExpression pe) {
        boolean oldInPropertyExpression = inPropertyExpression;
        Expression oldFoundArgs = foundArgs;
        Expression oldFoundConstant = foundConstant;
        inPropertyExpression = true;
        foundArgs = null;
        foundConstant = null;
        Expression objectExpression = transform(pe.getObjectExpression());

        if (foundArgs != null && foundConstant != null) {
            Expression result = findStaticMethodImportFromModule(foundConstant, foundArgs);
            if (result != null) {
                objectExpression = result;
            }
        }
        inPropertyExpression = oldInPropertyExpression;
        foundArgs = oldFoundArgs;
        foundConstant = oldFoundConstant;
        pe.setObjectExpression(objectExpression);
        return pe;
    }

    private Expression findStaticFieldOrPropAccessorImportFromModule(String name) {
        ModuleNode module = currentClass.getModule();
        if (module == null) return null;
        Map<String, ImportNode> importNodes = module.getStaticImports();
        Expression expression;
        String accessorName = getAccessorName(name);
        // look for one of these:
        //   import static MyClass.setProp [as setOtherProp]
        //   import static MyClass.getProp [as getOtherProp]
        // when resolving prop reference
        if (importNodes.containsKey(accessorName)) {
            ImportNode importNode = importNodes.get(accessorName);
            expression = findStaticPropertyAccessorByFullName(importNode.getType(), importNode.getFieldName());
            if (expression != null) return expression;
            expression = findStaticPropertyAccessor(importNode.getType(), getPropNameForAccessor(importNode.getFieldName()));
            if (expression != null) return expression;
        }
        if (accessorName.startsWith("get")) {
            accessorName = "is" + accessorName.substring(3);
            if (importNodes.containsKey(accessorName)) {
                ImportNode importNode = importNodes.get(accessorName);
                expression = findStaticPropertyAccessorByFullName(importNode.getType(), importNode.getFieldName());
                if (expression != null) return expression;
                expression = findStaticPropertyAccessor(importNode.getType(), getPropNameForAccessor(importNode.getFieldName()));
                if (expression != null) return expression;
            }
        }
        
        // look for one of these:
        //   import static MyClass.prop [as otherProp]
        // when resolving prop or field reference
        if (importNodes.containsKey(name)) {
            ImportNode importNode = importNodes.get(name);
            expression = findStaticPropertyAccessor(importNode.getType(), importNode.getFieldName());
            if (expression != null) return expression;
            expression = findStaticField(importNode.getType(), importNode.getFieldName());
            if (expression != null) return expression;
        }
        // look for one of these:
        //   import static MyClass.*
        // when resolving prop or field reference
        for (ImportNode importNode : module.getStaticStarImports().values()) {
            ClassNode node = importNode.getType();
            expression = findStaticPropertyAccessor(node, name);
            if (expression != null) return expression;
            expression = findStaticField(node, name);
            if (expression != null) return expression;
        }
        return null;
    }

    private Expression findStaticMethodImportFromModule(Expression method, Expression args) {
        ModuleNode module = currentClass.getModule();
        if (module == null || !(method instanceof ConstantExpression)) return null;
        Map<String, ImportNode> importNodes = module.getStaticImports();
        ConstantExpression ce = (ConstantExpression) method;
        Expression expression;
        Object value = ce.getValue();
        // skip non-Strings, e.g. Integer
        if (!(value instanceof String)) return null;
        final String name = (String) value;
        // look for one of these:
        //   import static SomeClass.method [as otherName]
        // when resolving methodCall() or getProp() or setProp()
        if (importNodes.containsKey(name)) {
            ImportNode importNode = importNodes.get(name);
            expression = findStaticMethod(importNode.getType(), importNode.getFieldName(), args);
            if (expression != null) return expression;
            expression = findStaticPropertyAccessorGivenArgs(importNode.getType(), getPropNameForAccessor(importNode.getFieldName()), args);
            if (expression != null) {
                return new StaticMethodCallExpression(importNode.getType(), importNode.getFieldName(), args);
            }
        }
        // look for one of these:
        //   import static SomeClass.someProp [as otherName]
        // when resolving getProp() or setProp()
        if (validPropName(name)) {
            String propName = getPropNameForAccessor(name);
            if (importNodes.containsKey(propName)) {
                ImportNode importNode = importNodes.get(propName);
                expression = findStaticMethod(importNode.getType(), prefix(name) + capitalize(importNode.getFieldName()), args);
                if (expression != null) return expression;
                expression = findStaticPropertyAccessorGivenArgs(importNode.getType(), importNode.getFieldName(), args);
                if (expression != null) {
                    return new StaticMethodCallExpression(importNode.getType(), prefix(name) + capitalize(importNode.getFieldName()), args);
                }
            }
        }
        Map<String, ImportNode> starImports = module.getStaticStarImports();
        ClassNode starImportType;
        if (currentClass.isEnum() && starImports.containsKey(currentClass.getName())) {
            ImportNode importNode = starImports.get(currentClass.getName());
            starImportType = importNode == null ? null : importNode.getType();
            expression = findStaticMethod(starImportType, name, args);
            if (expression != null) return expression;
        } else {
            for (ImportNode importNode : starImports.values()) {
                starImportType = importNode == null ? null : importNode.getType();
                expression = findStaticMethod(starImportType, name, args);
                if (expression != null) return expression;
                expression = findStaticPropertyAccessorGivenArgs(starImportType, getPropNameForAccessor(name), args);
                if (expression != null) {
                    return new StaticMethodCallExpression(starImportType, name, args);
                }
            }
        }
        return null;
    }

    private String prefix(String name) {
        return name.startsWith("is") ? "is" : name.substring(0, 3);
    }

    private String getPropNameForAccessor(String fieldName) {
        int prefixLength = fieldName.startsWith("is") ? 2 : 3;
        if (fieldName.length() < prefixLength + 1) return fieldName;
        if (!validPropName(fieldName)) return fieldName;
        return String.valueOf(fieldName.charAt(prefixLength)).toLowerCase() + fieldName.substring(prefixLength + 1);
    }

    private boolean validPropName(String propName) {
        return propName.startsWith("get") || propName.startsWith("is") || propName.startsWith("set");
    }

    private String getAccessorName(String name) {
        return (inLeftExpression ? "set" : "get") + capitalize(name);
    }

    private Expression findStaticPropertyAccessorGivenArgs(ClassNode staticImportType, String propName, Expression args) {
        // TODO validate args?
        return findStaticPropertyAccessor(staticImportType, propName);
    }

    private Expression findStaticPropertyAccessor(ClassNode staticImportType, String propName) {
        String accessorName = getAccessorName(propName);
        Expression accessor = findStaticPropertyAccessorByFullName(staticImportType, accessorName);
        if (accessor == null && accessorName.startsWith("get")) {
            accessor = findStaticPropertyAccessorByFullName(staticImportType, "is" + accessorName.substring(3));
        }
        if (accessor == null && hasStaticProperty(staticImportType, propName)) {
            // args will be replaced
            if (inLeftExpression)
                accessor = new StaticMethodCallExpression(staticImportType, accessorName, ArgumentListExpression.EMPTY_ARGUMENTS);
            else
                accessor = new PropertyExpression(new ClassExpression(staticImportType), propName);
        }
        return accessor;
    }

    private boolean hasStaticProperty(ClassNode staticImportType, String propName) {
        ClassNode classNode = staticImportType;
        while (classNode != null) {
            for (PropertyNode pn : classNode.getProperties()) {
                if (pn.getName().equals(propName) && pn.isStatic()) return true;
            }
            classNode = classNode.getSuperClass();
        }
        return false;
    }

    private Expression findStaticPropertyAccessorByFullName(ClassNode staticImportType, String accessorMethodName) {
        // anything will do as we only check size == 1
        ArgumentListExpression dummyArgs = new ArgumentListExpression();
        dummyArgs.addExpression(new EmptyExpression());
        return findStaticMethod(staticImportType, accessorMethodName, (inLeftExpression ? dummyArgs : ArgumentListExpression.EMPTY_ARGUMENTS));
    }

    private Expression findStaticField(ClassNode staticImportType, String fieldName) {
        if (staticImportType.isPrimaryClassNode() || staticImportType.isResolved()) {
            FieldNode field = staticImportType.getField(fieldName);
            if (field != null && field.isStatic())
                return new PropertyExpression(new ClassExpression(staticImportType), fieldName);
        }
        return null;
    }

    private Expression findStaticMethod(ClassNode staticImportType, String methodName, Expression args) {
        if (staticImportType.isPrimaryClassNode() || staticImportType.isResolved()) {
            if (staticImportType.hasPossibleStaticMethod(methodName, args)) {
                return new StaticMethodCallExpression(staticImportType, methodName, args);
            }
        }
        return null;
    }

    protected SourceUnit getSourceUnit() {
        return source;
    }
}

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