ExpressionStmt.java

// Copyright (C) 2005 Google Inc.
//
// 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.caja.parser.js;

import com.google.caja.lexer.FilePosition;

import java.util.List;

/**
 * A statement that contains an expression as its only child.  When control
 * reaches this statement, the expression is invoked, presumably for its side
 * effects, and the value is discarded.
 *
 * @author mikesamuel@gmail.com
 */
public final class ExpressionStmt extends AbstractStatement {
  private static final long serialVersionUID = 4277971387206538109L;

  /** @param value unused.  This ctor is provided for reflection. */
  @ReflectiveCtor
  public ExpressionStmt(
      FilePosition pos, Void value, List<? extends Expression> children) {
    this(pos, children.get(0));
  }

  public ExpressionStmt(FilePosition pos, Expression expr) {
    super(pos, Expression.class);
    ctorAppendChild(expr);
  }

  public ExpressionStmt(Expression expr) {
    super(expr.getFilePosition(), Expression.class);
    ctorAppendChild(expr);
  }

  @Override
  protected void childrenChanged() {
    if (1 != children().size()) { throw new IllegalStateException(); }
  }

  public Expression getExpression() { return (Expression) children().get(0); }

  @Override
  public Object getValue() { return null; }

 
  public boolean hasHangingConditional() { return false; }

}