https://openjdk.java.net/ 
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file:
 *
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package jdk.internal.org.objectweb.asm.util;

import jdk.internal.org.objectweb.asm.AnnotationVisitor;
import jdk.internal.org.objectweb.asm.Attribute;
import jdk.internal.org.objectweb.asm.FieldVisitor;
import jdk.internal.org.objectweb.asm.Opcodes;
import jdk.internal.org.objectweb.asm.TypePath;
import jdk.internal.org.objectweb.asm.TypeReference;


A FieldVisitor that checks that its methods are properly used. 
Author:Eric Bruneton
/**
 * A {@link FieldVisitor} that checks that its methods are properly used.
 *
 * @author Eric Bruneton
 */
public class CheckFieldAdapter extends FieldVisitor {

    
Whether the visitEnd method has been called. 
/** Whether the {@link #visitEnd} method has been called. */
    private boolean visitEndCalled;

    
Constructs a new CheckFieldAdapter. Subclasses must not use this constructor. Instead, they must use the CheckFieldAdapter(int, FieldVisitor) version. 
Params:
  • fieldVisitor – the field visitor to which this adapter must delegate calls.
Throws:
/**
      * Constructs a new {@link CheckFieldAdapter}. <i>Subclasses must not use this constructor</i>.
      * Instead, they must use the {@link #CheckFieldAdapter(int, FieldVisitor)} version.
      *
      * @param fieldVisitor the field visitor to which this adapter must delegate calls.
      * @throws IllegalStateException If a subclass calls this constructor.
      */
    public CheckFieldAdapter(final FieldVisitor fieldVisitor) {
        this(Opcodes.ASM7, fieldVisitor);
        if (getClass() != CheckFieldAdapter.class) {
            throw new IllegalStateException();
        }
    }

    
Constructs a new CheckFieldAdapter. 
Params:
/**
      * Constructs a new {@link CheckFieldAdapter}.
      *
      * @param api the ASM API version implemented by this visitor. Must be one of {@link
      *     Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6} or {@link Opcodes#ASM7}.
      * @param fieldVisitor the field visitor to which this adapter must delegate calls.
      */
    protected CheckFieldAdapter(final int api, final FieldVisitor fieldVisitor) {
        super(api, fieldVisitor);
    }

    @Override
    public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
        checkVisitEndNotCalled();
        // Annotations can only appear in V1_5 or more classes.
        CheckMethodAdapter.checkDescriptor(Opcodes.V1_5, descriptor, false);
        return new CheckAnnotationAdapter(super.visitAnnotation(descriptor, visible));
    }

    @Override
    public AnnotationVisitor visitTypeAnnotation(
            final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
        checkVisitEndNotCalled();
        int sort = new TypeReference(typeRef).getSort();
        if (sort != TypeReference.FIELD) {
            throw new IllegalArgumentException(
                    "Invalid type reference sort 0x" + Integer.toHexString(sort));
        }
        CheckClassAdapter.checkTypeRef(typeRef);
        CheckMethodAdapter.checkDescriptor(Opcodes.V1_5, descriptor, false);
        return new CheckAnnotationAdapter(
                super.visitTypeAnnotation(typeRef, typePath, descriptor, visible));
    }

    @Override
    public void visitAttribute(final Attribute attribute) {
        checkVisitEndNotCalled();
        if (attribute == null) {
            throw new IllegalArgumentException("Invalid attribute (must not be null)");
        }
        super.visitAttribute(attribute);
    }

    @Override
    public void visitEnd() {
        checkVisitEndNotCalled();
        visitEndCalled = true;
        super.visitEnd();
    }

    private void checkVisitEndNotCalled() {
        if (visitEndCalled) {
            throw new IllegalStateException("Cannot call a visit method after visitEnd has been called");
        }
    }
}