http://asm.objectweb.org/asm-tree/: A very small and fast Java bytecode manipulation framework (ObjectWeb)
  • Eric Bruneton
  • Eugene Kuleshov
  • Remi Forax 
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.
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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.tree;

import java.util.ArrayList;
import java.util.List;

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


A node that represents a field.

Author:Eric Bruneton
/**
 * A node that represents a field.
 * 
 * @author Eric Bruneton
 */
public class FieldNode extends FieldVisitor {

    
The field's access flags (see Opcodes). This field also indicates if the field is synthetic and/or deprecated. 
/**
     * The field's access flags (see {@link org.objectweb.asm.Opcodes}). This
     * field also indicates if the field is synthetic and/or deprecated.
     */
    public int access;

    
The field's name.

/**
     * The field's name.
     */
    public String name;

    
The field's descriptor (see Type). 
/**
     * The field's descriptor (see {@link org.objectweb.asm.Type}).
     */
    public String desc;

    
The field's signature. May be null.

/**
     * The field's signature. May be <tt>null</tt>.
     */
    public String signature;

    
The field's initial value. This field, which may be null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String. 
/**
     * The field's initial value. This field, which may be <tt>null</tt> if the
     * field does not have an initial value, must be an {@link Integer}, a
     * {@link Float}, a {@link Long}, a {@link Double} or a {@link String}.
     */
    public Object value;

    
The runtime visible annotations of this field. This list is a list of AnnotationNode objects. May be null.

@associatesorg.objectweb.asm.tree.AnnotationNode
@labelvisible
/**
     * The runtime visible annotations of this field. This list is a list of
     * {@link AnnotationNode} objects. May be <tt>null</tt>.
     * 
     * @associates org.objectweb.asm.tree.AnnotationNode
     * @label visible
     */
    public List<AnnotationNode> visibleAnnotations;

    
The runtime invisible annotations of this field. This list is a list of AnnotationNode objects. May be null.

@associatesorg.objectweb.asm.tree.AnnotationNode
@labelinvisible
/**
     * The runtime invisible annotations of this field. This list is a list of
     * {@link AnnotationNode} objects. May be <tt>null</tt>.
     * 
     * @associates org.objectweb.asm.tree.AnnotationNode
     * @label invisible
     */
    public List<AnnotationNode> invisibleAnnotations;

    
The runtime visible type annotations of this field. This list is a list of TypeAnnotationNode objects. May be null.

@associatesorg.objectweb.asm.tree.TypeAnnotationNode
@labelvisible
/**
     * The runtime visible type annotations of this field. This list is a list
     * of {@link TypeAnnotationNode} objects. May be <tt>null</tt>.
     * 
     * @associates org.objectweb.asm.tree.TypeAnnotationNode
     * @label visible
     */
    public List<TypeAnnotationNode> visibleTypeAnnotations;

    
The runtime invisible type annotations of this field. This list is a list of TypeAnnotationNode objects. May be null.

@associatesorg.objectweb.asm.tree.TypeAnnotationNode
@labelinvisible
/**
     * The runtime invisible type annotations of this field. This list is a list
     * of {@link TypeAnnotationNode} objects. May be <tt>null</tt>.
     * 
     * @associates org.objectweb.asm.tree.TypeAnnotationNode
     * @label invisible
     */
    public List<TypeAnnotationNode> invisibleTypeAnnotations;

    
The non standard attributes of this field. This list is a list of Attribute objects. May be null.

@associatesorg.objectweb.asm.Attribute
/**
     * The non standard attributes of this field. This list is a list of
     * {@link Attribute} objects. May be <tt>null</tt>.
     * 
     * @associates org.objectweb.asm.Attribute
     */
    public List<Attribute> attrs;

    
Constructs a new FieldNode. Subclasses must not use this
constructor. Instead, they must use the FieldNode(int, int, String, String, String, Object) version. 
Params:
  • access –  the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.
  • name – 
           the field's name.
  • desc –  the field's descriptor (see 
           Type).
  • signature – 
           the field's signature.
  • value – 
           the field's initial value. This parameter, which may be
           null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String.
Throws:
/**
     * Constructs a new {@link FieldNode}. <i>Subclasses must not use this
     * constructor</i>. Instead, they must use the
     * {@link #FieldNode(int, int, String, String, String, Object)} version.
     * 
     * @param access
     *            the field's access flags (see
     *            {@link org.objectweb.asm.Opcodes}). This parameter also
     *            indicates if the field is synthetic and/or deprecated.
     * @param name
     *            the field's name.
     * @param desc
     *            the field's descriptor (see {@link org.objectweb.asm.Type
     *            Type}).
     * @param signature
     *            the field's signature.
     * @param value
     *            the field's initial value. This parameter, which may be
     *            <tt>null</tt> if the field does not have an initial value,
     *            must be an {@link Integer}, a {@link Float}, a {@link Long}, a
     *            {@link Double} or a {@link String}.
     * @throws IllegalStateException
     *             If a subclass calls this constructor.
     */
    public FieldNode(final int access, final String name, final String desc,
            final String signature, final Object value) {
        this(Opcodes.ASM5, access, name, desc, signature, value);
        if (getClass() != FieldNode.class) {
            throw new IllegalStateException();
        }
    }

    
Constructs a new FieldNode. Subclasses must not use this
constructor.

Params:
  • api –  the ASM API version implemented by this visitor. Must be one of Opcodes.ASM4 or Opcodes.ASM5.
  • access –  the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.
  • name – 
           the field's name.
  • desc –  the field's descriptor (see 
           Type).
  • signature – 
           the field's signature.
  • value – 
           the field's initial value. This parameter, which may be
           null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String.
/**
     * Constructs a new {@link FieldNode}. <i>Subclasses must not use this
     * constructor</i>.
     * 
     * @param api
     *            the ASM API version implemented by this visitor. Must be one
     *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
     * @param access
     *            the field's access flags (see
     *            {@link org.objectweb.asm.Opcodes}). This parameter also
     *            indicates if the field is synthetic and/or deprecated.
     * @param name
     *            the field's name.
     * @param desc
     *            the field's descriptor (see {@link org.objectweb.asm.Type
     *            Type}).
     * @param signature
     *            the field's signature.
     * @param value
     *            the field's initial value. This parameter, which may be
     *            <tt>null</tt> if the field does not have an initial value,
     *            must be an {@link Integer}, a {@link Float}, a {@link Long}, a
     *            {@link Double} or a {@link String}.
     */
    public FieldNode(final int api, final int access, final String name,
            final String desc, final String signature, final Object value) {
        super(api);
        this.access = access;
        this.name = name;
        this.desc = desc;
        this.signature = signature;
        this.value = value;
    }

    // ------------------------------------------------------------------------
    // Implementation of the FieldVisitor abstract class
    // ------------------------------------------------------------------------

    @Override
    public AnnotationVisitor visitAnnotation(final String desc,
            final boolean visible) {
        AnnotationNode an = new AnnotationNode(desc);
        if (visible) {
            if (visibleAnnotations == null) {
                visibleAnnotations = new ArrayList<AnnotationNode>(1);
            }
            visibleAnnotations.add(an);
        } else {
            if (invisibleAnnotations == null) {
                invisibleAnnotations = new ArrayList<AnnotationNode>(1);
            }
            invisibleAnnotations.add(an);
        }
        return an;
    }

    @Override
    public AnnotationVisitor visitTypeAnnotation(int typeRef,
            TypePath typePath, String desc, boolean visible) {
        TypeAnnotationNode an = new TypeAnnotationNode(typeRef, typePath, desc);
        if (visible) {
            if (visibleTypeAnnotations == null) {
                visibleTypeAnnotations = new ArrayList<TypeAnnotationNode>(1);
            }
            visibleTypeAnnotations.add(an);
        } else {
            if (invisibleTypeAnnotations == null) {
                invisibleTypeAnnotations = new ArrayList<TypeAnnotationNode>(1);
            }
            invisibleTypeAnnotations.add(an);
        }
        return an;
    }

    @Override
    public void visitAttribute(final Attribute attr) {
        if (attrs == null) {
            attrs = new ArrayList<Attribute>(1);
        }
        attrs.add(attr);
    }

    @Override
    public void visitEnd() {
    }

    // ------------------------------------------------------------------------
    // Accept methods
    // ------------------------------------------------------------------------

    
Checks that this field node is compatible with the given ASM API version.
This methods checks that this node, and all its nodes recursively, do not
contain elements that were introduced in more recent versions of the ASM
API than the given version.

Params:
/**
     * Checks that this field node is compatible with the given ASM API version.
     * This methods checks that this node, and all its nodes recursively, do not
     * contain elements that were introduced in more recent versions of the ASM
     * API than the given version.
     * 
     * @param api
     *            an ASM API version. Must be one of {@link Opcodes#ASM4} or
     *            {@link Opcodes#ASM5}.
     */
    public void check(final int api) {
        if (api == Opcodes.ASM4) {
            if (visibleTypeAnnotations != null
                    && visibleTypeAnnotations.size() > 0) {
                throw new RuntimeException();
            }
            if (invisibleTypeAnnotations != null
                    && invisibleTypeAnnotations.size() > 0) {
                throw new RuntimeException();
            }
        }
    }

    
Makes the given class visitor visit this field.

Params:
  • cv – 
           a class visitor.
/**
     * Makes the given class visitor visit this field.
     * 
     * @param cv
     *            a class visitor.
     */
    public void accept(final ClassVisitor cv) {
        FieldVisitor fv = cv.visitField(access, name, desc, signature, value);
        if (fv == null) {
            return;
        }
        int i, n;
        n = visibleAnnotations == null ? 0 : visibleAnnotations.size();
        for (i = 0; i < n; ++i) {
            AnnotationNode an = visibleAnnotations.get(i);
            an.accept(fv.visitAnnotation(an.desc, true));
        }
        n = invisibleAnnotations == null ? 0 : invisibleAnnotations.size();
        for (i = 0; i < n; ++i) {
            AnnotationNode an = invisibleAnnotations.get(i);
            an.accept(fv.visitAnnotation(an.desc, false));
        }
        n = visibleTypeAnnotations == null ? 0 : visibleTypeAnnotations.size();
        for (i = 0; i < n; ++i) {
            TypeAnnotationNode an = visibleTypeAnnotations.get(i);
            an.accept(fv.visitTypeAnnotation(an.typeRef, an.typePath, an.desc,
                    true));
        }
        n = invisibleTypeAnnotations == null ? 0 : invisibleTypeAnnotations
                .size();
        for (i = 0; i < n; ++i) {
            TypeAnnotationNode an = invisibleTypeAnnotations.get(i);
            an.accept(fv.visitTypeAnnotation(an.typeRef, an.typePath, an.desc,
                    false));
        }
        n = attrs == null ? 0 : attrs.size();
        for (i = 0; i < n; ++i) {
            fv.visitAttribute(attrs.get(i));
        }
        fv.visitEnd();
    }
}