Java21InputAstVisitor.java

/*
 * Copyright 2023 The google-java-format 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 com.google.googlejavaformat.java.java21;

import com.google.googlejavaformat.OpsBuilder;
import com.google.googlejavaformat.java.java17.Java17InputAstVisitor;
import com.sun.source.tree.CaseTree;
import com.sun.source.tree.ConstantCaseLabelTree;
import com.sun.source.tree.DeconstructionPatternTree;
import com.sun.source.tree.DefaultCaseLabelTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.PatternCaseLabelTree;
import com.sun.source.tree.PatternTree;
import com.sun.source.tree.StringTemplateTree;
import javax.lang.model.element.Name;

/**
 * Extends {@link Java17InputAstVisitor} with support for AST nodes that were added or modified in
 * Java 21.
 */
public class Java21InputAstVisitor extends Java17InputAstVisitor {

  public Java21InputAstVisitor(OpsBuilder builder, int indentMultiplier) {
    super(builder, indentMultiplier);
  }

  @Override
  protected ExpressionTree getGuard(final CaseTree node) {
    return node.getGuard();
  }

  @Override
  public Void visitDefaultCaseLabel(DefaultCaseLabelTree node, Void unused) {
    token("default");
    return null;
  }

  @Override
  public Void visitPatternCaseLabel(PatternCaseLabelTree node, Void unused) {
    scan(node.getPattern(), null);
    return null;
  }

  @Override
  public Void visitConstantCaseLabel(ConstantCaseLabelTree node, Void aVoid) {
    scan(node.getConstantExpression(), null);
    return null;
  }

  @Override
  public Void visitDeconstructionPattern(DeconstructionPatternTree node, Void unused) {
    sync(node);
    scan(node.getDeconstructor(), null);
    builder.open(plusFour);
    token("(");
    builder.breakOp();
    boolean first = true;
    for (PatternTree pattern : node.getNestedPatterns()) {
      if (!first) {
        token(",");
        builder.breakOp(" ");
      }
      first = false;
      scan(pattern, null);
    }
    builder.close();
    token(")");
    return null;
  }

  @SuppressWarnings("preview")
  @Override
  public Void visitStringTemplate(StringTemplateTree node, Void unused) {
    sync(node);
    builder.open(plusFour);
    scan(node.getProcessor(), null);
    token(".");
    token(builder.peekToken().get());
    for (int i = 0; i < node.getFragments().size() - 1; i++) {
      token("{");
      builder.breakOp();
      scan(node.getExpressions().get(i), null);
      token("}");
      token(builder.peekToken().get());
    }
    builder.close();
    return null;
  }

  @Override
  protected void variableName(Name name) {
    if (name.isEmpty()) {
      token("_");
    } else {
      visit(name);
    }
  }
}