有没有办法为速度指令类进行依赖注入？

Question

我有一个类似于here描述的自定义速度指令。

package ca.sergiy.velocity;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.directive.Directive;
import org.apache.velocity.runtime.log.Log;
import org.apache.velocity.runtime.parser.node.ASTBlock;
import org.apache.velocity.runtime.parser.node.Node;

public class TruncateBlockDirective extends Directive {

    private Log log;

    private int maxLength;
    private String suffix;
    private Boolean truncateAtWord;

    public String getName() {
        return "truncateBlock";
    }

    public int getType() {
        return BLOCK;
    }

    @Override
    public void init(RuntimeServices rs, InternalContextAdapter context, Node node) throws TemplateInitException {
        super.init(rs, context, node);
        log = rs.getLog();

        //read dafault values from config
        maxLength = rs.getInt("userdirective.truncateBlock.maxLength", 10);
        suffix = rs.getString("userdirective.truncateBlock.suffix", "...");
        truncateAtWord = rs.getBoolean("userdirective.truncateBlock.truncateAtWord", false);

    }

    public boolean render(InternalContextAdapter context, Writer writer, Node node) 
            throws IOException, ResourceNotFoundException, ParseErrorException, MethodInvocationException {

        log.debug("truncateBlock directive render() call");

        String truncateMe = null;

        //default settings
        int maxLength = this.maxLength;
        String suffix = this.suffix;
        Boolean truncateAtWord = this.truncateAtWord;

        //loop through all "params"
        for(int i=0; i<node.jjtGetNumChildren(); i++) {
            if (node.jjtGetChild(i) != null ) {
                if(!(node.jjtGetChild(i) instanceof ASTBlock)) {
                    //reading and casting inline parameters
                    if(i == 0) {
                        maxLength = (Integer)node.jjtGetChild(i).value(context);
                    } else if(i == 1) {
                        suffix = String.valueOf(node.jjtGetChild(i).value(context));
                    } else if(i == 2) {
                        truncateAtWord = (Boolean)node.jjtGetChild(i).value(context);
                    } else {
                        break;
                    }
                } else {
                    //reading block content and rendering it  
                    StringWriter blockContent = new StringWriter();
                    node.jjtGetChild(i).render(context, blockContent);

                    truncateMe = blockContent.toString();
                    break;
                }
            }
        }

        //truncate and write result to writer
        try {
            writer.write(truncate(truncateMe, maxLength, suffix, truncateAtWord));
        } catch (Exception e) {
            String msg = "Truncate failed";
            log.error(msg, e);
            throw new RuntimeException(msg, e);

        }
        return true;

    }

    //does actual truncating (taken directly from DisplayTools)
    public String truncate(String truncateMe, int maxLength, String suffix,
            boolean truncateAtWord) {
        if (truncateMe == null || maxLength <= 0) {
            return null;
        }

        if (truncateMe.length() <= maxLength) {
            return truncateMe;
        }
        if (suffix == null || maxLength - suffix.length() <= 0) {
            // either no need or no room for suffix
            return truncateMe.substring(0, maxLength);
        }
        if (truncateAtWord) {
            // find the latest space within maxLength
            int lastSpace = truncateMe.substring(0, maxLength - suffix.length() + 1).lastIndexOf(" ");
            if (lastSpace > suffix.length()) {
                return truncateMe.substring(0, lastSpace) + suffix;
            }
        }
        // truncate to exact character and append suffix
        return truncateMe.substring(0, maxLength - suffix.length()) + suffix;

    }

}

有没有办法使用spring将服务注入到这样的指令中，或者唯一的可能是将bean作为指令参数传递？