asmifierabstractvisitor.java

jboss规则引擎

/***
 * 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.drools.asm.util;

import java.util.HashMap;

import org.drools.asm.AnnotationVisitor;
import org.drools.asm.Attribute;
import org.drools.asm.Type;
import org.drools.asm.util.attrs.ASMifiable;

/**
 * An abstract ASMifier visitor.
 * 
 * @author Eric Bruneton
 */
public class ASMifierAbstractVisitor extends AbstractVisitor {

    /**
     * The name of the variable for this visitor in the produced code.
     */
    protected String name;

    /**
     * The label names. This map associates String values to Label keys. It is
     * used only in ASMifierMethodVisitor.
     */
    HashMap          labelNames;

    /**
     * Constructs a new {@link ASMifierAbstractVisitor}.
     * 
     * @param name the name of the variable for this visitor in the produced
     *        code.
     */
    protected ASMifierAbstractVisitor(final String name) {
        this.name = name;
    }

    /**
     * Prints the ASM code that generates the given annotation.
     * 
     * @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.
     */
    public AnnotationVisitor visitAnnotation(final String desc,
                                             final boolean visible) {
        this.buf.setLength( 0 );
        this.buf.append( "{\n" ).append( "av0 = " ).append( this.name ).append( ".visitAnnotation(" );
        appendConstant( desc );
        this.buf.append( ", " ).append( visible ).append( ");\n" );
        this.text.add( this.buf.toString() );
        final ASMifierAnnotationVisitor av = new ASMifierAnnotationVisitor( 0 );
        this.text.add( av.getText() );
        this.text.add( "}\n" );
        return av;
    }

    /**
     * Prints the ASM code that generates the given attribute.
     * 
     * @param attr an attribute.
     */
    public void visitAttribute(final Attribute attr) {
        this.buf.setLength( 0 );
        if ( attr instanceof ASMifiable ) {
            this.buf.append( "{\n" );
            this.buf.append( "// ATTRIBUTE\n" );
            ((ASMifiable) attr).asmify( this.buf,
                                        "attr",
                                        this.labelNames );
            this.buf.append( this.name ).append( ".visitAttribute(attr);\n" );
            this.buf.append( "}\n" );
        } else {
            this.buf.append( "// WARNING! skipped a non standard attribute of type \"" );
            this.buf.append( attr.type ).append( "\"\n" );
        }
        this.text.add( this.buf.toString() );
    }

    /**
     * Prints the ASM code to end the visit.
     */
    public void visitEnd() {
        this.buf.setLength( 0 );
        this.buf.append( this.name ).append( ".visitEnd();\n" );
        this.text.add( this.buf.toString() );
    }

    /**
     * Appends a string representation of the given constant to the given
     * buffer.
     * 
     * @param cst an {@link Integer}, {@link Float}, {@link Long},
     *        {@link Double} or {@link String} object. May be <tt>null</tt>.
     */
    void appendConstant(final Object cst) {
        appendConstant( this.buf,
                        cst );
    }

    /**
     * Appends a string representation of the given constant to the given
     * buffer.
     * 
     * @param buf a string buffer.
     * @param cst an {@link Integer}, {@link Float}, {@link Long},
     *        {@link Double} or {@link String} object. May be <tt>null</tt>.
     */
    static void appendConstant(final StringBuffer buf,
                               final Object cst) {
        if ( cst == null ) {
            buf.append( "null" );
        } else if ( cst instanceof String ) {
            appendString( buf,
                          (String) cst );
        } else if ( cst instanceof Type ) {
            buf.append( "Type.getType(\"" );
            buf.append( ((Type) cst).getDescriptor() );
            buf.append( "\")" );
        } else if ( cst instanceof Byte ) {
            buf.append( "new Byte((byte)" ).append( cst ).append( ")" );
        } else if ( cst instanceof Boolean ) {
            buf.append( "new Boolean(" ).append( cst ).append( ")" );
        } else if ( cst instanceof Short ) {
            buf.append( "new Short((short)" ).append( cst ).append( ")" );
        } else if ( cst instanceof Character ) {
            final int c = ((Character) cst).charValue();
            buf.append( "new Character((char)" ).append( c ).append( ")" );
        } else if ( cst instanceof Integer ) {
            buf.append( "new Integer(" ).append( cst ).append( ")" );
        } else if ( cst instanceof Float ) {
            buf.append( "new Float(\"" ).append( cst ).append( "\")" );
        } else if ( cst instanceof Long ) {
            buf.append( "new Long(" ).append( cst ).append( "L)" );
        } else if ( cst instanceof Double ) {
            buf.append( "new Double(\"" ).append( cst ).append( "\")" );
        } else if ( cst instanceof byte[] ) {
            final byte[] v = (byte[]) cst;
            buf.append( "new byte[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] );
            }
            buf.append( "}" );
        } else if ( cst instanceof boolean[] ) {
            final boolean[] v = (boolean[]) cst;
            buf.append( "new boolean[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] );
            }
            buf.append( "}" );
        } else if ( cst instanceof short[] ) {
            final short[] v = (short[]) cst;
            buf.append( "new short[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( "(short)" ).append( v[i] );
            }
            buf.append( "}" );
        } else if ( cst instanceof char[] ) {
            final char[] v = (char[]) cst;
            buf.append( "new char[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( "(char)" ).append( (int) v[i] );
            }
            buf.append( "}" );
        } else if ( cst instanceof int[] ) {
            final int[] v = (int[]) cst;
            buf.append( "new int[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] );
            }
            buf.append( "}" );
        } else if ( cst instanceof long[] ) {
            final long[] v = (long[]) cst;
            buf.append( "new long[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] ).append( "L" );
            }
            buf.append( "}" );
        } else if ( cst instanceof float[] ) {
            final float[] v = (float[]) cst;
            buf.append( "new float[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] ).append( "f" );
            }
            buf.append( "}" );
        } else if ( cst instanceof double[] ) {
            final double[] v = (double[]) cst;
            buf.append( "new double[] {" );
            for ( int i = 0; i < v.length; i++ ) {
                buf.append( i == 0 ? "" : "," ).append( v[i] ).append( "d" );
            }
            buf.append( "}" );
        }
    }
}