annotationnode.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.tree;

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

import org.drools.asm.AnnotationVisitor;

/**
 * A node that represents an annotationn.
 * 
 * @author Eric Bruneton
 */
public class AnnotationNode
    implements
    AnnotationVisitor {

    /**
     * The class descriptor of the annotation class.
     */
    public String desc;

    /**
     * The name value pairs of this annotation. Each name value pair is stored
     * as two consecutive elements in the list. The name is a {@link String},
     * and the value may be a {@link Byte}, {@link Boolean}, {@link Character},
     * {@link Short}, {@link Integer}, {@link Long}, {@link Float},
     * {@link Double}, {@link String} or {@link org.drools.asm.Type}, or an
     * two elements String array (for enumeration values), a
     * {@link AnnotationNode}, or a {@link List} of values of one of the
     * preceding types. The list may be <tt>null</tt> if there is no name
     * value pair.
     */
    public List   values;

    /**
     * Constructs a new {@link AnnotationNode}.
     * 
     * @param desc the class descriptor of the annotation class.
     */
    public AnnotationNode(final String desc) {
        this.desc = desc;
    }

    /**
     * Constructs a new {@link AnnotationNode} to visit an array value.
     * 
     * @param values where the visited values must be stored.
     */
    AnnotationNode(final List values) {
        this.values = values;
    }

    // ------------------------------------------------------------------------
    // Implementation of the AnnotationVisitor interface
    // ------------------------------------------------------------------------

    public void visit(final String name,
                      final Object value) {
        if ( this.values == null ) {
            this.values = new ArrayList( this.desc != null ? 2 : 1 );
        }
        if ( this.desc != null ) {
            this.values.add( name );
        }
        this.values.add( value );
    }

    public void visitEnum(final String name,
                          final String desc,
                          final String value) {
        if ( this.values == null ) {
            this.values = new ArrayList( this.desc != null ? 2 : 1 );
        }
        if ( this.desc != null ) {
            this.values.add( name );
        }
        this.values.add( new String[]{desc, value} );
    }

    public AnnotationVisitor visitAnnotation(final String name,
                                             final String desc) {
        if ( this.values == null ) {
            this.values = new ArrayList( this.desc != null ? 2 : 1 );
        }
        if ( this.desc != null ) {
            this.values.add( name );
        }
        final AnnotationNode annotation = new AnnotationNode( desc );
        this.values.add( annotation );
        return annotation;
    }

    public AnnotationVisitor visitArray(final String name) {
        if ( this.values == null ) {
            this.values = new ArrayList( this.desc != null ? 2 : 1 );
        }
        if ( this.desc != null ) {
            this.values.add( name );
        }
        final List array = new ArrayList();
        this.values.add( array );
        return new AnnotationNode( array );
    }

    public void visitEnd() {
    }

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

    /**
     * Makes the given visitor visit this annotation.
     * 
     * @param av an annotation visitor.
     */
    public void accept(final AnnotationVisitor av) {
        if ( this.values != null ) {
            for ( int i = 0; i < this.values.size(); i += 2 ) {
                final String name = (String) this.values.get( i );
                final Object value = this.values.get( i + 1 );
                accept( av,
                        name,
                        value );
            }
        }
        av.visitEnd();
    }

    /**
     * Makes the given visitor visit a given annotation value.
     * 
     * @param av an annotation visitor.
     * @param name the value name.
     * @param value the actual value.
     */
    static void accept(final AnnotationVisitor av,
                       final String name,
                       final Object value) {
        if ( value instanceof String[] ) {
            final String[] typeconst = (String[]) value;
            av.visitEnum( name,
                          typeconst[0],
                          typeconst[1] );
        } else if ( value instanceof AnnotationNode ) {
            final AnnotationNode an = (AnnotationNode) value;
            an.accept( av.visitAnnotation( name,
                                           an.desc ) );
        } else if ( value instanceof List ) {
            final AnnotationVisitor v = av.visitArray( name );
            final List array = (List) value;
            for ( int j = 0; j < array.size(); ++j ) {
                accept( v,
                        null,
                        array.get( j ) );
            }
            v.visitEnd();
        } else {
            av.visit( name,
                      value );
        }
    }
}