iteratetag.java

这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用struts,hebinate,xml等技术,有丰富的tag,role,navigation,session,dictio

	protected String styleClass = "rescontent";
	public String getStyleClass() {
		return (this.styleClass);
	}
	public void setStyleClass(String styleClass) {
		this.styleClass = styleClass;
	}

	
	protected String rendTr = "false";
	public String getRendTr() {
		return (this.rendTr);
	}
	public void setRendTr(String rendTr) {
		this.rendTr = rendTr;
	}	
	
	private void writeTrBegin() throws JspException{
		if( rendTr.equals("true") ){
			StringBuffer results = new StringBuffer();
			results.append("<tr class=\"");
			results.append( styleClass);	
			results.append("\">\n");
			ResponseUtils.write(pageContext, results.toString());
		}
	}
	private void writeTrEnd() throws JspException{
		if( rendTr.equals("true") ){
			StringBuffer results = new StringBuffer();
			results.append("</tr>\n");
			ResponseUtils.write(pageContext, results.toString());
		}
	}
//add by steven end
    // --------------------------------------------------------- Public Methods

    /**
     * Construct an iterator for the specified collection, and begin
     * looping through the body once per element.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

        // Acquire the collection we are going to iterate over
		logger.debug("Start iterate:minLengthCount<"+minLengthCount+">");
        Object collection = this.collection;
        if (collection == null) {
            collection = RequestUtils.lookup(pageContext, name, property, scope);
        }

//        if (collection == null) {
//            JspException e = new JspException(messages.getMessage("iterate.collection"));
//            RequestUtils.saveException(pageContext, e);
//            throw e;
//        }

		if( minLength!=null ){
			try {
				if( minLengthValue == -1)
				  minLengthValue = Integer.parseInt(minLength);
			} catch (NumberFormatException e) {
				minLengthValue = -1;
			}			
		}
		logger.debug("Start iterate:minLengthValue<"+minLengthValue+">");
		minLengthCount++;
		writeTrBegin();
		if( collection == null ){
			logger.info("collection is null in logic:iterate,SKIP_BODY");
			if( minLengthValue == -1) return SKIP_BODY;
			if( minLengthCount > minLengthValue ){
				return (SKIP_BODY);
			}
			
			return (EVAL_BODY_TAG);
		}
        // Construct an iterator for this collection
        if (collection.getClass().isArray()) {
            try {
                // If we're lucky, it is an array of objects
                // that we can iterate over with no copying
                iterator = Arrays.asList((Object[]) collection).iterator();
            } catch (ClassCastException e) {
                // Rats -- it is an array of primitives
                int length = Array.getLength(collection);
                ArrayList c = new ArrayList(length);
                for (int i = 0; i < length; i++) {
                    c.add(Array.get(collection, i));
                }
                iterator = c.iterator();
            }
        } else if (collection instanceof Collection) {
            iterator = ((Collection) collection).iterator();
        } else if (collection instanceof Iterator) {
            iterator = (Iterator) collection;
        } else if (collection instanceof Map) {
            iterator = ((Map) collection).entrySet().iterator();
        } else if (collection instanceof Enumeration) {
            iterator = IteratorUtils.asIterator((Enumeration) collection);
        } else {
            JspException e = new JspException(messages.getMessage("iterate.iterator"));
            RequestUtils.saveException(pageContext, e);
            throw e;
        }

        // Calculate the starting offset
        if (offset == null) {
            offsetValue = 0;
        } else {
            try {
                offsetValue = Integer.parseInt(offset);
            } catch (NumberFormatException e) {
                Integer offsetObject = (Integer) RequestUtils.lookup(pageContext, offset, null);
                if (offsetObject == null) {
                    offsetValue = 0;
                } else {
                    offsetValue = offsetObject.intValue();
                }
            }
        }
        if (offsetValue < 0) {
            offsetValue = 0;
        }

        // Calculate the rendering length
        if (length == null) {
            lengthValue = 0;
        } else {
            try {
                lengthValue = Integer.parseInt(length);
            } catch (NumberFormatException e) {
                Integer lengthObject = (Integer) RequestUtils.lookup(pageContext, length, null);
                if (lengthObject == null) {
                    lengthValue = 0;
                } else {
                    lengthValue = lengthObject.intValue();
                }
            }
        }
        if (lengthValue < 0) {
            lengthValue = 0;
        }
        lengthCount = 0;
		

        // Skip the leading elements up to the starting offset
        for (int i = 0; i < offsetValue; i++) {
            if (iterator.hasNext()) {
                iterator.next();
            }
        }

        // Store the first value and evaluate, or skip the body if none
        if (iterator.hasNext()) {
            Object element = iterator.next();
            if (element == null) {
                pageContext.removeAttribute(id);
            } else {
                pageContext.setAttribute(id, element);
            }
            lengthCount++;
            started = true;
            if (indexId != null) {
                pageContext.setAttribute(indexId, new Integer(getIndex()));
            }
			writeTrBegin();
            return (EVAL_BODY_TAG);
        } else {
			if( minLengthValue == -1) return SKIP_BODY;
			else {
				writeTrBegin();
				return (EVAL_BODY_TAG);
			} 
            
        }

    }

    /**
     * Make the next collection element available and loop, or
     * finish the iterations if there are no more elements.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doAfterBody() throws JspException {
		writeTrEnd();
        // Render the output from this iteration to the output stream
        if (bodyContent != null) {
            ResponseUtils.writePrevious(pageContext, bodyContent.getString());
            bodyContent.clearBody();
        }
		minLengthCount++;

        // Decide whether to iterate or quit
        if ((lengthValue > 0) && (lengthCount >= lengthValue)) {
            return (SKIP_BODY);
        }
		
		if( minLengthValue != -1 && iterator == null ) {
			if( minLengthValue > (minLengthCount-1) ){
				writeTrBegin();
				return (EVAL_BODY_TAG);
			}else{
				return (SKIP_BODY);
			}	
		}	
		
        if ( iterator.hasNext()) {
            Object element = iterator.next();
            if (element == null) {
                pageContext.removeAttribute(id);
            } else {
                pageContext.setAttribute(id, element);
            }
            
            lengthCount++;
            if (indexId != null) {
                pageContext.setAttribute(indexId, new Integer(getIndex()));
            }
			
			writeTrBegin();
            return (EVAL_BODY_TAG);
        } else if( minLengthValue != -1) {
			pageContext.removeAttribute(id);
			if( minLengthValue > (minLengthCount-1) ){
				writeTrBegin();
				return (EVAL_BODY_TAG);
			}else{
				return (SKIP_BODY);
			}			
        }else{
			return (SKIP_BODY);
        }

    }

    /**
     * Clean up after processing this enumeration.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {

        // Clean up our started state
        started = false;
        iterator = null;
		minLengthCount = 0;
        // Continue processing this page
        return (EVAL_PAGE);

    }

    /**
     * Release all allocated resources.
     */
    public void release() {

        super.release();

        iterator = null;
        lengthCount = 0;
        lengthValue = 0;
        offsetValue = 0;

        id = null;
        collection = null;
        length = null;
        name = null;
        offset = null;
        property = null;
        scope = null;
        started = false;

    }

}