iteratetaghandler.java

本套系统采用了业界当前最为流行的beanAction组件

/*
 *  Copyright 2004 Clinton Begin
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.ibatis.sqlmap.engine.mapping.sql.dynamic.elements;

import com.ibatis.common.beans.Probe;
import com.ibatis.common.beans.ProbeFactory;

public class IterateTagHandler extends BaseTagHandler {

  private static final Probe PROBE = ProbeFactory.getProbe();

  public int doStartFragment(SqlTagContext ctx, SqlTag tag, Object parameterObject) {
    IterateContext iterate = (IterateContext) ctx.getAttribute(tag);
    if (iterate == null) {
      IterateContext parentIterate = ctx.peekIterateContext();
      
      ctx.pushRemoveFirstPrependMarker(tag);
      
      Object collection;
      String prop = tag.getPropertyAttr();
      if (prop != null && !prop.equals("")) {
          if(null != parentIterate && parentIterate.isAllowNext()){
            parentIterate.next();
            parentIterate.setAllowNext(false);
            if(!parentIterate.hasNext()) {
              parentIterate.setFinal(true);
            }
          }
          
          if (parentIterate != null) {
              prop = parentIterate.addIndexToTagProperty(prop);
          }
          
        collection = PROBE.getObject(parameterObject, prop);
      } else {
        collection = parameterObject;
      }
      iterate = new IterateContext(collection,tag, parentIterate);
      
      iterate.setProperty( null == prop ? "" : prop );
      
      ctx.setAttribute(tag, iterate);
      ctx.pushIterateContext(iterate);
    } else if ("iterate".equals(tag.getRemoveFirstPrepend())) {
      ctx.reEnableRemoveFirstPrependMarker();
    }
    
    if (iterate != null && iterate.hasNext()) {
      return INCLUDE_BODY;
    } else {
      return SKIP_BODY;
    }
  }

  public int doEndFragment(SqlTagContext ctx, SqlTag tag, Object parameterObject, StringBuffer bodyContent) {
    IterateContext iterate = (IterateContext) ctx.getAttribute(tag);

    if (iterate.hasNext() || iterate.isFinal()) {
      
      if(iterate.isAllowNext()) {
        iterate.next();
      }

      if (bodyContent.toString().trim().length() > 0) {
        // the sub element produced a result.  If it is the first one
        // to produce a result, then we need to add the open
        // text.  If it is not the first to produce a result then
        // we need to add the conjunction text
        if (iterate.someSubElementsHaveContent()) {
          if (tag.isConjunctionAvailable()) {
            bodyContent.insert(0, tag.getConjunctionAttr());
          }
        } else {
            // we need to specify that this is the first content
            // producing element so that the doPrepend method will
            // add the prepend
            iterate.setPrependEnabled(true);
            
            if (tag.isOpenAvailable()) {
              bodyContent.insert(0, tag.getOpenAttr());
            }
        }
        iterate.setSomeSubElementsHaveContent(true);
      }
      
      if (iterate.isLast() && iterate.someSubElementsHaveContent()) {
        if (tag.isCloseAvailable()) {
          bodyContent.append(tag.getCloseAttr());
        }
      }
      
      iterate.setAllowNext(true);
      if(iterate.isFinal()) {
        return super.doEndFragment(ctx,tag,parameterObject,bodyContent);
      } else {
        return REPEAT_BODY;
      }

    } else {
      return super.doEndFragment(ctx,tag,parameterObject,bodyContent);
    }
  }

  public void doPrepend(SqlTagContext ctx, SqlTag tag, Object parameterObject, StringBuffer bodyContent) {
    IterateContext iterate = (IterateContext) ctx.getAttribute(tag);
    if (iterate.isPrependEnabled()) {
      super.doPrepend(ctx, tag, parameterObject, bodyContent);
      iterate.setPrependEnabled(false);  // only do the prepend one time
    }
  }

  public boolean isPostParseRequired() {
    return true;
  }

}