10. Reference Contributor
引用是实现自定义语言支持中最重要和最棘手的部分之一.
解析引用意味着能够从元素的使用转变为声明，完成，重命名重构，查找用法等.
每个可以重命名或引用的元素都需要实现com.intellij.psi.PsiNamedElement接口.
10.1.
定义一个名为element的基类
package com.simpleplugin.psi;
import com.intellij.psi.PsiNameIdentifierOwner;
public interface SimpleNamedElement extends PsiNameIdentifierOwner {
}
package com.simpleplugin.psi.impl;
import com.intellij.extapi.psi.ASTWrapperPsiElement;
import com.intellij.lang.ASTNode;
import com.simpleplugin.psi.SimpleNamedElement;
import org.jetbrains.annotations.NotNull;
public abstract class SimpleNamedElementImpl extends ASTWrapperPsiElement implements SimpleNamedElement {
public SimpleNamedElementImpl(@NotNull ASTNode node) {
super(node);
}
}
10.2.
为生成的PSI元素定义辅助方法
由于我们需要在PSI类中实现新方法，我们应该在SimplePsiImplUtil类中定义它们:
public class SimplePsiImplUtil {
// ...
public static String getName(SimpleProperty element) {
return getKey(element);
}
public static PsiElement setName(SimpleProperty element, String newName) {
ASTNode keyNode = element.getNode().findChildByType(SimpleTypes.KEY);
if (keyNode != null) {
SimpleProperty property = SimpleElementFactory.createProperty(element.getProject(), newName);
ASTNode newKeyNode = property.getFirstChild().getNode();
element.getNode().replaceChild(keyNode, newKeyNode);
}
return element;
}
public static PsiElement getNameIdentifier(SimpleProperty element) {
ASTNode keyNode = element.getNode().findChildByType(SimpleTypes.KEY);
if (keyNode != null) {
return keyNode.getPsi();
} else {
return null;
}
}
// ...
}
请注意，SimpleElementFactory类将显示为错误.
我们接下来会创建它.
10.3.
定义元素工厂
package com.simpleplugin.psi;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
import com.simpleplugin.SimpleFileType;
public class SimpleElementFactory {
public static SimpleProperty createProperty(Project project, String name) {
final SimpleFile file = createFile(project, name);
return (SimpleProperty) file.getFirstChild();
}
public static SimpleFile createFile(Project project, String text) {
String name = "dummy.simple";
return (SimpleFile) PsiFileFactory.getInstance(project).
createFileFromText(name, SimpleFileType.INSTANCE, text);
}
}
10.4.
更新语法并重新生成解析器
现在我们需要对语法文件进行相应的更改并重新生成解析器和PSI类.
property ::= (KEY? SEPARATOR VALUE?) | KEY {mixin="com.simpleplugin.psi.impl.SimpleNamedElementImpl"
implements="com.simpleplugin.psi.SimpleNamedElement" methods=[getKey getValue getName setName getNameIdentifier]}
不要忘记重新生成解析器!
右键单击Simple.bnf文件并选择_Generate Parser Code_.
10.5.
定义参考
现在我们需要定义一个引用类来解析它的用法属性.
package com.simpleplugin;
import com.intellij.codeInsight.lookup.*;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.TextRange;
import com.intellij.psi.*;
import com.simpleplugin.psi.SimpleProperty;
import org.jetbrains.annotations.*;
import java.util.*;
public class SimpleReference extends PsiReferenceBase<PsiElement> implements PsiPolyVariantReference {
private String key;
public SimpleReference(@NotNull PsiElement element, TextRange textRange) {
super(element, textRange);
key = element.getText().substring(textRange.getStartOffset(), textRange.getEndOffset());
}
@NotNull
@Override
public ResolveResult[] multiResolve(boolean incompleteCode) {
Project project = myElement.getProject();
final List<SimpleProperty> properties = SimpleUtil.findProperties(project, key);
List<ResolveResult> results = new ArrayList<ResolveResult>();
for (SimpleProperty property : properties) {
results.add(new PsiElementResolveResult(property));
}
return results.toArray(new ResolveResult[results.size()]);
}
@Nullable
@Override
public PsiElement resolve() {
ResolveResult[] resolveResults = multiResolve(false);
return resolveResults.length == 1 ? resolveResults[0].getElement() : null;
}
@NotNull
@Override
public Object[] getVariants() {
Project project = myElement.getProject();
List<SimpleProperty> properties = SimpleUtil.findProperties(project);
List<LookupElement> variants = new ArrayList<LookupElement>();
for (final SimpleProperty property : properties) {
if (property.getKey() != null && property.getKey().length() > 0) {
variants.add(LookupElementBuilder.create(property).
withIcon(SimpleIcons.FILE).
withTypeText(property.getContainingFile().getName())
);
}
}
return variants.toArray();
}
}
10.6.
定义参考贡献者
引用参与者允许您提供从其他语言(如Java)中的元素到您所用语言中的元素的引用.
让我们为每个属性的使用贡献一个参考.
package com.simpleplugin;
import com.intellij.openapi.util.TextRange;
import com.intellij.patterns.PlatformPatterns;
import com.intellij.psi.*;
import com.intellij.util.ProcessingContext;
import org.jetbrains.annotations.NotNull;
public class SimpleReferenceContributor extends PsiReferenceContributor {
@Override
public void registerReferenceProviders(@NotNull PsiReferenceRegistrar registrar) {
registrar.registerReferenceProvider(PlatformPatterns.psiElement(PsiLiteralExpression.class),
new PsiReferenceProvider() {
@NotNull
@Override
public PsiReference[] getReferencesByElement(@NotNull PsiElement element,
@NotNull ProcessingContext
context) {
PsiLiteralExpression literalExpression = (PsiLiteralExpression) element;
String value = literalExpression.getValue() instanceof String ?
(String) literalExpression.getValue() : null;
if (value != null && value.startsWith("simple" + ":")) {
return new PsiReference[]{
new SimpleReference(element, new TextRange(8, value.length() + 1))};
}
return PsiReference.EMPTY_ARRAY;
}
});
}
}
10.7.
注册参考贡献者
<psi.referenceContributor implementation="com.simpleplugin.SimpleReferenceContributor"/>
10.8.
运行该项目
如您所见，IDE现在解析了该属性并提供了完成功能.
根据定义和用法重命名重构.
10.9.
定义重构支持提供程序
为了允许就地重构，我们应该在重构支持提供程序中明确指定它.
package com.simpleplugin;
import com.intellij.lang.refactoring.RefactoringSupportProvider;
import com.intellij.psi.PsiElement;
import com.simpleplugin.psi.SimpleProperty;
public class SimpleRefactoringSupportProvider extends RefactoringSupportProvider {
@Override
public boolean isMemberInplaceRenameAvailable(PsiElement element, PsiElement context) {
return element instanceof SimpleProperty;
}
}
10.10.
注册重构支持提供程序
<lang.refactoringSupport language="Simple" implementationClass="com.simpleplugin.SimpleRefactoringSupportProvider"/>
10.11.
运行该项目
Last modified: 11 May 2019