diff options
Diffstat (limited to 'eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/refactorings/extractstring/ReplaceStringsVisitor.java')
| -rw-r--r-- | eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/refactorings/extractstring/ReplaceStringsVisitor.java | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/refactorings/extractstring/ReplaceStringsVisitor.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/refactorings/extractstring/ReplaceStringsVisitor.java new file mode 100644 index 000000000..e058ce1ba --- /dev/null +++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/refactorings/extractstring/ReplaceStringsVisitor.java @@ -0,0 +1,480 @@ +/* + * Copyright (C) 2009 The Android Open Source Project + * + * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php + * + * 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 com.android.ide.eclipse.adt.internal.refactorings.extractstring; + +import org.eclipse.jdt.core.dom.AST; +import org.eclipse.jdt.core.dom.ASTNode; +import org.eclipse.jdt.core.dom.ASTVisitor; +import org.eclipse.jdt.core.dom.Assignment; +import org.eclipse.jdt.core.dom.ClassInstanceCreation; +import org.eclipse.jdt.core.dom.Expression; +import org.eclipse.jdt.core.dom.IMethodBinding; +import org.eclipse.jdt.core.dom.ITypeBinding; +import org.eclipse.jdt.core.dom.IVariableBinding; +import org.eclipse.jdt.core.dom.MethodDeclaration; +import org.eclipse.jdt.core.dom.MethodInvocation; +import org.eclipse.jdt.core.dom.Modifier; +import org.eclipse.jdt.core.dom.Name; +import org.eclipse.jdt.core.dom.SimpleName; +import org.eclipse.jdt.core.dom.SimpleType; +import org.eclipse.jdt.core.dom.SingleVariableDeclaration; +import org.eclipse.jdt.core.dom.StringLiteral; +import org.eclipse.jdt.core.dom.Type; +import org.eclipse.jdt.core.dom.TypeDeclaration; +import org.eclipse.jdt.core.dom.VariableDeclarationExpression; +import org.eclipse.jdt.core.dom.VariableDeclarationFragment; +import org.eclipse.jdt.core.dom.VariableDeclarationStatement; +import org.eclipse.jdt.core.dom.rewrite.ASTRewrite; +import org.eclipse.text.edits.TextEditGroup; + +import java.util.ArrayList; +import java.util.List; +import java.util.TreeMap; + +/** + * Visitor used by {@link ExtractStringRefactoring} to extract a string from an existing + * Java source and replace it by an Android XML string reference. + * + * @see ExtractStringRefactoring#computeJavaChanges + */ +class ReplaceStringsVisitor extends ASTVisitor { + + private static final String CLASS_ANDROID_CONTEXT = "android.content.Context"; //$NON-NLS-1$ + private static final String CLASS_JAVA_CHAR_SEQUENCE = "java.lang.CharSequence"; //$NON-NLS-1$ + private static final String CLASS_JAVA_STRING = "java.lang.String"; //$NON-NLS-1$ + + + private final AST mAst; + private final ASTRewrite mRewriter; + private final String mOldString; + private final String mRQualifier; + private final String mXmlId; + private final ArrayList<TextEditGroup> mEditGroups; + + public ReplaceStringsVisitor(AST ast, + ASTRewrite astRewrite, + ArrayList<TextEditGroup> editGroups, + String oldString, + String rQualifier, + String xmlId) { + mAst = ast; + mRewriter = astRewrite; + mEditGroups = editGroups; + mOldString = oldString; + mRQualifier = rQualifier; + mXmlId = xmlId; + } + + @SuppressWarnings("unchecked") + @Override + public boolean visit(StringLiteral node) { + if (node.getLiteralValue().equals(mOldString)) { + + // We want to analyze the calling context to understand whether we can + // just replace the string literal by the named int constant (R.id.foo) + // or if we should generate a Context.getString() call. + boolean useGetResource = false; + useGetResource = examineVariableDeclaration(node) || + examineMethodInvocation(node) || + examineAssignment(node); + + Name qualifierName = mAst.newName(mRQualifier + ".string"); //$NON-NLS-1$ + SimpleName idName = mAst.newSimpleName(mXmlId); + ASTNode newNode = mAst.newQualifiedName(qualifierName, idName); + boolean disabledChange = false; + String title = "Replace string by ID"; + + if (useGetResource) { + Expression context = methodHasContextArgument(node); + if (context == null && !isClassDerivedFromContext(node)) { + // if we don't have a class that derives from Context and + // we don't have a Context method argument, then try a bit harder: + // can we find a method or a field that will give us a context? + context = findContextFieldOrMethod(node); + + if (context == null) { + // If not, let's write Context.getString(), which is technically + // invalid but makes it a good clue on how to fix it. Since these + // will not compile, we create a disabled change by default. + context = mAst.newSimpleName("Context"); //$NON-NLS-1$ + disabledChange = true; + } + } + + MethodInvocation mi2 = mAst.newMethodInvocation(); + mi2.setName(mAst.newSimpleName("getString")); //$NON-NLS-1$ + mi2.setExpression(context); + mi2.arguments().add(newNode); + + newNode = mi2; + title = "Replace string by Context.getString(R.string...)"; + } + + TextEditGroup editGroup = new EnabledTextEditGroup(title, !disabledChange); + mEditGroups.add(editGroup); + mRewriter.replace(node, newNode, editGroup); + } + return super.visit(node); + } + + /** + * Examines if the StringLiteral is part of an assignment corresponding to the + * a string variable declaration, e.g. String foo = id. + * + * The parent fragment is of syntax "var = expr" or "var[] = expr". + * We want the type of the variable, which is either held by a + * VariableDeclarationStatement ("type [fragment]") or by a + * VariableDeclarationExpression. In either case, the type can be an array + * but for us all that matters is to know whether the type is an int or + * a string. + */ + private boolean examineVariableDeclaration(StringLiteral node) { + VariableDeclarationFragment fragment = findParentClass(node, + VariableDeclarationFragment.class); + + if (fragment != null) { + ASTNode parent = fragment.getParent(); + + Type type = null; + if (parent instanceof VariableDeclarationStatement) { + type = ((VariableDeclarationStatement) parent).getType(); + } else if (parent instanceof VariableDeclarationExpression) { + type = ((VariableDeclarationExpression) parent).getType(); + } + + if (type instanceof SimpleType) { + return isJavaString(type.resolveBinding()); + } + } + + return false; + } + + /** + * Examines if the StringLiteral is part of a assignment to a variable that + * is a string. We need to lookup the variable to find its type, either in the + * enclosing method or class type. + */ + private boolean examineAssignment(StringLiteral node) { + + Assignment assignment = findParentClass(node, Assignment.class); + if (assignment != null) { + Expression left = assignment.getLeftHandSide(); + + ITypeBinding typeBinding = left.resolveTypeBinding(); + return isJavaString(typeBinding); + } + + return false; + } + + /** + * If the expression is part of a method invocation (aka a function call) or a + * class instance creation (aka a "new SomeClass" constructor call), we try to + * find the type of the argument being used. If it is a String (most likely), we + * want to return true (to generate a getString() call). However if there might + * be a similar method that takes an int, in which case we don't want to do that. + * + * This covers the case of Activity.setTitle(int resId) vs setTitle(String str). + */ + @SuppressWarnings("rawtypes") + private boolean examineMethodInvocation(StringLiteral node) { + + ASTNode parent = null; + List arguments = null; + IMethodBinding methodBinding = null; + + MethodInvocation invoke = findParentClass(node, MethodInvocation.class); + if (invoke != null) { + parent = invoke; + arguments = invoke.arguments(); + methodBinding = invoke.resolveMethodBinding(); + } else { + ClassInstanceCreation newclass = findParentClass(node, ClassInstanceCreation.class); + if (newclass != null) { + parent = newclass; + arguments = newclass.arguments(); + methodBinding = newclass.resolveConstructorBinding(); + } + } + + if (parent != null && arguments != null && methodBinding != null) { + // We want to know which argument this is. + // Walk up the hierarchy again to find the immediate child of the parent, + // which should turn out to be one of the invocation arguments. + ASTNode child = null; + for (ASTNode n = node; n != parent; ) { + ASTNode p = n.getParent(); + if (p == parent) { + child = n; + break; + } + n = p; + } + if (child == null) { + // This can't happen: a parent of 'node' must be the child of 'parent'. + return false; + } + + // Find the index + int index = 0; + for (Object arg : arguments) { + if (arg == child) { + break; + } + index++; + } + + if (index == arguments.size()) { + // This can't happen: one of the arguments of 'invoke' must be 'child'. + return false; + } + + // Eventually we want to determine if the parameter is a string type, + // in which case a Context.getString() call must be generated. + boolean useStringType = false; + + // Find the type of that argument + ITypeBinding[] types = methodBinding.getParameterTypes(); + if (index < types.length) { + ITypeBinding type = types[index]; + useStringType = isJavaString(type); + } + + // Now that we know that this method takes a String parameter, can we find + // a variant that would accept an int for the same parameter position? + if (useStringType) { + String name = methodBinding.getName(); + ITypeBinding clazz = methodBinding.getDeclaringClass(); + nextMethod: for (IMethodBinding mb2 : clazz.getDeclaredMethods()) { + if (methodBinding == mb2 || !mb2.getName().equals(name)) { + continue; + } + // We found a method with the same name. We want the same parameters + // except that the one at 'index' must be an int type. + ITypeBinding[] types2 = mb2.getParameterTypes(); + int len2 = types2.length; + if (types.length == len2) { + for (int i = 0; i < len2; i++) { + if (i == index) { + ITypeBinding type2 = types2[i]; + if (!("int".equals(type2.getQualifiedName()))) { //$NON-NLS-1$ + // The argument at 'index' is not an int. + continue nextMethod; + } + } else if (!types[i].equals(types2[i])) { + // One of the other arguments do not match our original method + continue nextMethod; + } + } + // If we got here, we found a perfect match: a method with the same + // arguments except the one at 'index' is an int. In this case we + // don't need to convert our R.id into a string. + useStringType = false; + break; + } + } + } + + return useStringType; + } + return false; + } + + /** + * Examines if the StringLiteral is part of a method declaration (a.k.a. a function + * definition) which takes a Context argument. + * If such, it returns the name of the variable as a {@link SimpleName}. + * Otherwise it returns null. + */ + private SimpleName methodHasContextArgument(StringLiteral node) { + MethodDeclaration decl = findParentClass(node, MethodDeclaration.class); + if (decl != null) { + for (Object obj : decl.parameters()) { + if (obj instanceof SingleVariableDeclaration) { + SingleVariableDeclaration var = (SingleVariableDeclaration) obj; + if (isAndroidContext(var.getType())) { + return mAst.newSimpleName(var.getName().getIdentifier()); + } + } + } + } + return null; + } + + /** + * Walks up the node hierarchy to find the class (aka type) where this statement + * is used and returns true if this class derives from android.content.Context. + */ + private boolean isClassDerivedFromContext(StringLiteral node) { + TypeDeclaration clazz = findParentClass(node, TypeDeclaration.class); + if (clazz != null) { + // This is the class that the user is currently writing, so it can't be + // a Context by itself, it has to be derived from it. + return isAndroidContext(clazz.getSuperclassType()); + } + return false; + } + + private Expression findContextFieldOrMethod(StringLiteral node) { + TypeDeclaration clazz = findParentClass(node, TypeDeclaration.class); + return clazz == null ? null : findContextFieldOrMethod(clazz.resolveBinding()); + } + + private Expression findContextFieldOrMethod(ITypeBinding clazzType) { + TreeMap<Integer, Expression> results = new TreeMap<Integer, Expression>(); + findContextCandidates(results, clazzType, 0 /*superType*/); + if (results.size() > 0) { + Integer bestRating = results.keySet().iterator().next(); + return results.get(bestRating); + } + return null; + } + + /** + * Find all method or fields that are candidates for providing a Context. + * There can be various choices amongst this class or its super classes. + * Sort them by rating in the results map. + * + * The best ever choice is to find a method with no argument that returns a Context. + * The second suitable choice is to find a Context field. + * The least desirable choice is to find a method with arguments. It's not really + * desirable since we can't generate these arguments automatically. + * + * Methods and fields from supertypes are ignored if they are private. + * + * The rating is reversed: the lowest rating integer is used for the best candidate. + * Because the superType argument is actually a recursion index, this makes the most + * immediate classes more desirable. + * + * @param results The map that accumulates the rating=>expression results. The lower + * rating number is the best candidate. + * @param clazzType The class examined. + * @param superType The recursion index. + * 0 for the immediate class, 1 for its super class, etc. + */ + private void findContextCandidates(TreeMap<Integer, Expression> results, + ITypeBinding clazzType, + int superType) { + for (IMethodBinding mb : clazzType.getDeclaredMethods()) { + // If we're looking at supertypes, we can't use private methods. + if (superType != 0 && Modifier.isPrivate(mb.getModifiers())) { + continue; + } + + if (isAndroidContext(mb.getReturnType())) { + // We found a method that returns something derived from Context. + + int argsLen = mb.getParameterTypes().length; + if (argsLen == 0) { + // We'll favor any method that takes no argument, + // That would be the best candidate ever, so we can stop here. + MethodInvocation mi = mAst.newMethodInvocation(); + mi.setName(mAst.newSimpleName(mb.getName())); + results.put(Integer.MIN_VALUE, mi); + return; + } else { + // A method with arguments isn't as interesting since we wouldn't + // know how to populate such arguments. We'll use it if there are + // no other alternatives. We'll favor the one with the less arguments. + Integer rating = Integer.valueOf(10000 + 1000 * superType + argsLen); + if (!results.containsKey(rating)) { + MethodInvocation mi = mAst.newMethodInvocation(); + mi.setName(mAst.newSimpleName(mb.getName())); + results.put(rating, mi); + } + } + } + } + + // A direct Context field would be more interesting than a method with + // arguments. Try to find one. + for (IVariableBinding var : clazzType.getDeclaredFields()) { + // If we're looking at supertypes, we can't use private field. + if (superType != 0 && Modifier.isPrivate(var.getModifiers())) { + continue; + } + + if (isAndroidContext(var.getType())) { + // We found such a field. Let's use it. + Integer rating = Integer.valueOf(superType); + results.put(rating, mAst.newSimpleName(var.getName())); + break; + } + } + + // Examine the super class to see if we can locate a better match + clazzType = clazzType.getSuperclass(); + if (clazzType != null) { + findContextCandidates(results, clazzType, superType + 1); + } + } + + /** + * Walks up the node hierarchy and returns the first ASTNode of the requested class. + * Only look at parents. + * + * Implementation note: this is a generic method so that it returns the node already + * casted to the requested type. + */ + @SuppressWarnings("unchecked") + private <T extends ASTNode> T findParentClass(ASTNode node, Class<T> clazz) { + if (node != null) { + for (node = node.getParent(); node != null; node = node.getParent()) { + if (node.getClass().equals(clazz)) { + return (T) node; + } + } + } + return null; + } + + /** + * Returns true if the given type is or derives from android.content.Context. + */ + private boolean isAndroidContext(Type type) { + if (type != null) { + return isAndroidContext(type.resolveBinding()); + } + return false; + } + + /** + * Returns true if the given type is or derives from android.content.Context. + */ + private boolean isAndroidContext(ITypeBinding type) { + for (; type != null; type = type.getSuperclass()) { + if (CLASS_ANDROID_CONTEXT.equals(type.getQualifiedName())) { + return true; + } + } + return false; + } + + /** + * Returns true if this type binding represents a String or CharSequence type. + */ + private boolean isJavaString(ITypeBinding type) { + for (; type != null; type = type.getSuperclass()) { + if (CLASS_JAVA_STRING.equals(type.getQualifiedName()) || + CLASS_JAVA_CHAR_SEQUENCE.equals(type.getQualifiedName())) { + return true; + } + } + return false; + } +} |