ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2011 INRIA, France Telecom
All rights reserved.
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modification, are permitted provided that the following conditions
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   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
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   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.
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/***
 * 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 org.objectweb.asm.util;

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

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

    private boolean end;

    
Constructs a new CheckFieldAdapter. Subclasses must not use
this constructor. Instead, they must use the CheckFieldAdapter(int, FieldVisitor) version. 
Params:
fv – 
           the field visitor to which this adapter must delegate calls.
Throws:
IllegalStateException – 
            If a subclass calls this constructor./**
     * Constructs a new {@link CheckFieldAdapter}. <i>Subclasses must not use
     * this constructor</i>. Instead, they must use the
     * {@link #CheckFieldAdapter(int, FieldVisitor)} version.
     * 
     * @param fv
     *            the field visitor to which this adapter must delegate calls.
     * @throws IllegalStateException
     *             If a subclass calls this constructor.
     */
    public CheckFieldAdapter(final FieldVisitor fv) {
        this(Opcodes.ASM5, fv);
        if (getClass() != CheckFieldAdapter.class) {
            throw new IllegalStateException();
        }
    }

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

    @Override
    public AnnotationVisitor visitAnnotation(final String desc,
            final boolean visible) {
        checkEnd();
        CheckMethodAdapter.checkDesc(desc, false);
        return new CheckAnnotationAdapter(super.visitAnnotation(desc, visible));
    }

    @Override
    public AnnotationVisitor visitTypeAnnotation(final int typeRef,
            final TypePath typePath, final String desc, final boolean visible) {
        checkEnd();
        int sort = typeRef >>> 24;
        if (sort != TypeReference.FIELD) {
            throw new IllegalArgumentException("Invalid type reference sort 0x"
                    + Integer.toHexString(sort));
        }
        CheckClassAdapter.checkTypeRefAndPath(typeRef, typePath);
        CheckMethodAdapter.checkDesc(desc, false);
        return new CheckAnnotationAdapter(super.visitTypeAnnotation(typeRef,
                typePath, desc, visible));
    }

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

    @Override
    public void visitEnd() {
        checkEnd();
        end = true;
        super.visitEnd();
    }

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