methodvisitor.java

asm的源码包 并且包含英文的文档

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 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;

/**
 * A visitor to visit a Java method. The methods of this interface must be
 * called in the following order: [ <tt>visitAnnotationDefault</tt> ] (
 * <tt>visitAnnotation</tt> | <tt>visitParameterAnnotation</tt> |
 * <tt>visitAttribute</tt> )* [ <tt>visitCode</tt> ( <tt>visitFrame</tt> |
 * <tt>visit</tt><i>X</i>Insn</tt> | <tt>visitLabel</tt> | <tt>visitTryCatchBlock</tt> |
 * <tt>visitLocalVariable</tt> | <tt>visitLineNumber</tt>)* <tt>visitMaxs</tt> ]
 * <tt>visitEnd</tt>. In addition, the <tt>visit</tt><i>X</i>Insn</tt>
 * and <tt>visitLabel</tt> methods must be called in the sequential order of
 * the bytecode instructions of the visited code, <tt>visitTryCatchBlock</tt>
 * must be called <i>before</i> the labels passed as arguments have been
 * visited, and the <tt>visitLocalVariable</tt> and <tt>visitLineNumber</tt>
 * methods must be called <i>after</i> the labels passed as arguments have been
 * visited.
 * 
 * @author Eric Bruneton
 */
public interface MethodVisitor {

    // -------------------------------------------------------------------------
    // Annotations and non standard attributes
    // -------------------------------------------------------------------------

    /**
     * Visits the default value of this annotation interface method.
     * 
     * @return a visitor to the visit the actual default value of this
     *         annotation interface method, or <tt>null</tt> if this visitor
     *         is not interested in visiting this default value. The 'name'
     *         parameters passed to the methods of this annotation visitor are
     *         ignored. Moreover, exacly one visit method must be called on this
     *         annotation visitor, followed by visitEnd.
     */
    AnnotationVisitor visitAnnotationDefault();

    /**
     * Visits an annotation of this method.
     * 
     * @param desc the class descriptor of the annotation class.
     * @param visible <tt>true</tt> if the annotation is visible at runtime.
     * @return a visitor to visit the annotation values, or <tt>null</tt> if
     *         this visitor is not interested in visiting this annotation.
     */
    AnnotationVisitor visitAnnotation(String desc, boolean visible);

    /**
     * Visits an annotation of a parameter this method.
     * 
     * @param parameter the parameter index.
     * @param desc the class descriptor of the annotation class.
     * @param visible <tt>true</tt> if the annotation is visible at runtime.
     * @return a visitor to visit the annotation values, or <tt>null</tt> if
     *         this visitor is not interested in visiting this annotation.
     */
    AnnotationVisitor visitParameterAnnotation(
        int parameter,
        String desc,
        boolean visible);

    /**
     * Visits a non standard attribute of this method.
     * 
     * @param attr an attribute.
     */
    void visitAttribute(Attribute attr);

    /**
     * Starts the visit of the method's code, if any (i.e. non abstract method).
     */
    void visitCode();

    /**
     * Visits the current state of the local variables and operand stack
     * elements. This method must(*) be called <i>just before</i> any
     * instruction <b>i</b> that follows an unconditionnal branch instruction
     * such as GOTO or THROW, that is the target of a jump instruction, or that
     * starts an exception handler block. The visited types must describe the
     * values of the local variables and of the operand stack elements <i>just
     * before</i> <b>i</b> is executed. <br> <br> (*) this is mandatory only
     * for classes whose version is greater than or equal to
     * {@link Opcodes#V1_6 V1_6}. <br> <br> Packed frames are basically
     * "deltas" from the state of the previous frame (very first frame is
     * implicitly defined by the method's parameters and access flags): <ul>
     * <li>{@link Opcodes#F_SAME} representing frame with exactly the same
     * locals as the previous frame and with the empty stack.</li> <li>{@link Opcodes#F_SAME1}
     * representing frame with exactly the same locals as the previous frame and
     * with single value on the stack (<code>nStack</code> is 1 and
     * <code>stack[0]</code> contains value for the type of the stack item).</li>
     * <li>{@link Opcodes#F_APPEND} representing frame with current locals are
     * the same as the locals in the previous frame, except that additional
     * locals are defined (<code>nLocal</code> is 1, 2 or 3 and
     * <code>local</code> elements contains values representing added types).</li>
     * <li>{@link Opcodes#F_CHOP} representing frame with current locals are
     * the same as the locals in the previous frame, except that the last 1-3
     * locals are absent and with the empty stack (<code>nLocals</code> is 1,
     * 2 or 3). </li> <li>{@link Opcodes#F_FULL} representing complete frame
     * data.</li> </li> </ul>
     * 
     * @param type the type of this stack map frame. Must be
     *        {@link Opcodes#F_NEW} for expanded frames, or
     *        {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND},
     *        {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or
     *        {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for compressed
     *        frames.
     * @param nLocal the number of local variables in the visited frame.
     * @param local the local variable types in this frame. This array must not
     *        be modified. Primitive types are represented by
     *        {@link Opcodes#TOP}, {@link Opcodes#INTEGER},
     *        {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
     *        {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
     *        {@link Opcodes#UNINITIALIZED_THIS} (long and double are
     *        represented by a single element). Reference types are represented
     *        by String objects (representing internal names, or type
     *        descriptors for array types), and uninitialized types by Label
     *        objects (this label designates the NEW instruction that created
     *        this uninitialized value).
     * @param nStack the number of operand stack elements in the visited frame.
     * @param stack the operand stack types in this frame. This array must not
     *        be modified. Its content has the same format as the "local" array.
     */
    void visitFrame(
        int type,
        int nLocal,
        Object[] local,
        int nStack,
        Object[] stack);

    // -------------------------------------------------------------------------
    // Normal instructions
    // -------------------------------------------------------------------------

    /**
     * Visits a zero operand instruction.
     * 
     * @param opcode the opcode of the instruction to be visited. This opcode is
     *        either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2,
     *        ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0,
     *        FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD,
     *        DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE,
     *        DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP,
     *        DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD,
     *        DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV,
     *        FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL,
     *        LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR,
     *        I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B,
     *        I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN,
     *        FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW,
     *        MONITORENTER, or MONITOREXIT.
     */
    void visitInsn(int opcode);

    /**
     * Visits an instruction with a single int operand.
     * 
     * @param opcode the opcode of the instruction to be visited. This opcode is
     *        either BIPUSH, SIPUSH or NEWARRAY.
     * @param operand the operand of the instruction to be visited.<br> When
     *        opcode is BIPUSH, operand value should be between Byte.MIN_VALUE
     *        and Byte.MAX_VALUE.<br> When opcode is SIPUSH, operand value
     *        should be between Short.MIN_VALUE and Short.MAX_VALUE.<br> When
     *        opcode is NEWARRAY, operand value should be one of
     *        {@link Opcodes#T_BOOLEAN}, {@link Opcodes#T_CHAR},
     *        {@link Opcodes#T_FLOAT}, {@link Opcodes#T_DOUBLE},
     *        {@link Opcodes#T_BYTE}, {@link Opcodes#T_SHORT},
     *        {@link Opcodes#T_INT} or {@link Opcodes#T_LONG}.
     */
    void visitIntInsn(int opcode, int operand);