trunk/core/src/main/java/org/apache/struts2/views/jsp/iterator/SubsetIteratorTag.java - struts - Git at Google

 /*
  * $Id$
  *
  * Copyright 2006 The Apache Software Foundation.
  *
  * 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 org.apache.struts2.views.jsp.iterator;

 import javax.servlet.jsp.JspException;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.struts2.util.SubsetIteratorFilter;
 import org.apache.struts2.util.SubsetIteratorFilter.Decider;
 import org.apache.struts2.views.jsp.StrutsBodyTagSupport;


 /**
  * <!-- START SNIPPET: javadoc -->
  * <b>NOTE: JSP-TAG</b>
  *
  * <p>A tag that takes an iterator and outputs a subset of it. It delegates to
  * {@link org.apache.struts2.util.SubsetIteratorFilter} internally to
  * perform the subset functionality.</p>
  * <!-- END SNIPPET: javadoc -->
  *
  * <!-- START SNIPPET: params -->
  * <ul>
  * 		<li>count (Object) - Indicate the number of entries to be in the resulting subset iterator</li>
  * 		<li>source* (Object) - Indicate the source of which the resulting subset iterator is to be derived base on</li>
  * 		<li>start (Object) - Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator</li>
  * 		<li>decider (Object) - Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator</li>
  * 		<li>id (String) - Indicate the pageContext attribute id to store the resultant subset iterator in</li>
  * </ul>
  * <!-- END SNIPPET: params -->
  *
  *
  * <pre>
  * <!-- START SNIPPET: action -->
  * public class MySubsetTagAction extends ActionSupport {
  *      public String execute() throws Exception {
  *		   l = new ArrayList();
  *		   l.add(new Integer(1));
  *		   l.add(new Integer(2));
  *		   l.add(new Integer(3));
  *		   l.add(new Integer(4));
  *		   l.add(new Integer(5));
  *		   return "done";
  *	    }
  *
  *
  *	    public Integer[] getMyArray() {
  *		   return a;
  *	    }
  *
  *	    public List getMyList() {
  *		   return l;
  *	     }
  *
  *      public Decider getMyDecider() {
  *		return new Decider() {
  *			public boolean decide(Object element) throws Exception {
  *				int i = ((Integer)element).intValue();
  *				return (((i % 2) == 0)?true:false);
  *			}
  *		};
  *		}
  *	}
  * <!-- END SNIPPET: action -->
  * </pre>
  *
  *
  * <pre>
  * <!-- START SNIPPET: example1 -->
  * &lt;!-- s: List basic --&gt;
  *    &lt;s:subset source="myList"&gt;
  *	     &lt;s:iterator&gt;
  *		    &lt;s:property /&gt;
  *	     &lt;/s:iterator&gt;
  *    &lt;/s:subset&gt;
  * <!-- END SNIPPET: example1 -->
  * </pre>
  *
  * <pre>
  * <!-- START SNIPPET: example2 -->
  * &lt;!-- B: List with count --&gt;
  *    &lt;s:subset source="myList" count="3"&gt;
  * 	     &lt;s:iterator&gt;
  * 		     &lt;s:property /&gt;
  * 	     &lt;/s:iterator&gt;
  *     &lt;/s:subset&gt;
  * <!-- END SNIPPET: example2 -->
  * </pre>
  *
  * <pre>
  * <!-- START SNIPPET: example3 -->
  * &lt;!--  C: List with start -->
  *      &lt;s:subset source="myList" count="13" start="3"&gt;
  * 	       &lt;s:iterator&gt;
  * 		     &lt;s:property /&gt;
  * 	       &lt;/s:iterator&gt;
  *      &lt;/s:subset&gt;
  * <!-- END SNIPPET: example3 -->
  * </pre>
  *
  * <pre>
  * <!-- START SNIPPET: example4 -->
  * &lt;!--  D: List with id --&gt;
  *      &lt;s:subset id="mySubset" source="myList" count="13" start="3" /&gt;
  *      &lt;%
  * 	        Iterator i = (Iterator) pageContext.getAttribute("mySubset");
  *          while(i.hasNext()) {
  *      %&gt;
  *      &lt;%=i.next() %&gt;
  *      &lt;%  } %&gt;
  * <!-- END SNIPPET: example4 -->
  * </pre>
  *
  * <pre>
  * <!-- START SNIPPET: example5 -->
  *  &lt;!--  D: List with Decider --&gt;
  *      &lt;s:subset source="myList" decider="myDecider"&gt;
  * 	           &lt;s:iterator&gt;
  *		            &lt;s:property /&gt;
  *	           &lt;/s:iterator&gt;
  *      &lt;/s:subset&gt;
  * <!-- END SNIPPET: example5 -->
  * </pre>
  *
  *
  * @s.tag name="subset" tld-body-content="JSP"
  * description="Takes an iterator and outputs a subset of it"
  */
 public class SubsetIteratorTag extends StrutsBodyTagSupport {

 	private static final long serialVersionUID = -6252696081713080102L;

 	private static final Log _log = LogFactory.getLog(SubsetIteratorTag.class);

     String countAttr;
     String sourceAttr;
     String startAttr;
     String deciderAttr;

     SubsetIteratorFilter subsetIteratorFilter = null;


     /**
      * @s.tagattribute required="false" type="Integer"
      * description="Indicate the number of entries to be in the resulting subset iterator"
      */
     public void setCount(String count) {
         countAttr = count;
     }

     /**
      * @s.tagattribute required="false"
      * description="Indicate the source of which the resulting subset iterator is to be derived base on"
      */
     public void setSource(String source) {
         sourceAttr = source;
     }

     /**
      * @s.tagattribute required="false" type="Integer"
      * description="Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator"
      */
     public void setStart(String start) {
         startAttr = start;
     }

     /**
      * @s.tagattribute required="false" type="org.apache.struts2.util.SubsetIteratorFilter.Decider"
      * description="Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator"
      */
     public void setDecider(String decider) {
     	deciderAttr = decider;
     }


     public int doStartTag() throws JspException {

         // source
         Object source = null;
         if (sourceAttr == null && sourceAttr.length() <= 0) {
         	source = findValue("top");
         } else {
             source = findValue(sourceAttr);
         }

         // count
         int count = -1;
     	if (countAttr != null && countAttr.length() > 0) {
     		Object countObj = findValue(countAttr);
     		if (countObj instanceof Integer) {
     			count = ((Integer)countObj).intValue();
     		}
     		else if (countObj instanceof Float) {
     			count = ((Float)countObj).intValue();
     		}
     		else if (countObj instanceof Long) {
     			count = ((Long)countObj).intValue();
     		}
     		else if (countObj instanceof Double) {
     			count = ((Long)countObj).intValue();
     		}
     		else if (countObj instanceof String) {
     			try {
     				count = Integer.parseInt((String)countObj);
     			}
     			catch(NumberFormatException e) {
     				_log.warn("unable to convert count attribute ["+countObj+"] to number, ignore count attribute", e);
     			}
     		}
     	}

         // start
     	int start = 0;
         if (startAttr != null && startAttr.length() > 0) {
             Object startObj = findValue(startAttr);
             if (startObj instanceof Integer) {
     			start = ((Integer)startObj).intValue();
     		}
     		else if (startObj instanceof Float) {
     			start = ((Float)startObj).intValue();
     		}
     		else if (startObj instanceof Long) {
     			start = ((Long)startObj).intValue();
     		}
     		else if (startObj instanceof Double) {
     			start = ((Long)startObj).intValue();
     		}
     		else if (startObj instanceof String) {
     			try {
     				start = Integer.parseInt((String)startObj);
     			}
     			catch(NumberFormatException e) {
     				_log.warn("unable to convert count attribute ["+startObj+"] to number, ignore count attribute", e);
     			}
     		}
         }

         // decider
         Decider decider = null;
         if (deciderAttr != null && deciderAttr.length() > 0) {
         	Object deciderObj = findValue(deciderAttr);
         	if (! (deciderObj instanceof Decider)) {
         		throw new JspException("decider found from stack ["+deciderObj+"] does not implement "+Decider.class);
         	}
         	decider = (Decider) deciderObj;
         }


         subsetIteratorFilter = new SubsetIteratorFilter();
         subsetIteratorFilter.setCount(count);
         subsetIteratorFilter.setDecider(decider);
         subsetIteratorFilter.setSource(source);
         subsetIteratorFilter.setStart(start);
         subsetIteratorFilter.execute();

         getStack().push(subsetIteratorFilter);
         if (getId() != null) {
         	pageContext.setAttribute(getId(), subsetIteratorFilter);
         }

         return EVAL_BODY_INCLUDE;
     }

     public int doEndTag() throws JspException {

     	getStack().pop();

     	subsetIteratorFilter = null;

     	return EVAL_PAGE;
     }
 }
	/*
	* $Id$
	*
	* Copyright 2006 The Apache Software Foundation.
	*
	* 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 org.apache.struts2.views.jsp.iterator;

	import javax.servlet.jsp.JspException;

	import org.apache.commons.logging.Log;
	import org.apache.commons.logging.LogFactory;
	import org.apache.struts2.util.SubsetIteratorFilter;
	import org.apache.struts2.util.SubsetIteratorFilter.Decider;
	import org.apache.struts2.views.jsp.StrutsBodyTagSupport;


	/**
	* <!-- START SNIPPET: javadoc -->
	* <b>NOTE: JSP-TAG</b>
	*
	* <p>A tag that takes an iterator and outputs a subset of it. It delegates to
	* {@link org.apache.struts2.util.SubsetIteratorFilter} internally to
	* perform the subset functionality.</p>
	* <!-- END SNIPPET: javadoc -->
	*
	* <!-- START SNIPPET: params -->
	* <ul>
	* <li>count (Object) - Indicate the number of entries to be in the resulting subset iterator</li>
	* <li>source* (Object) - Indicate the source of which the resulting subset iterator is to be derived base on</li>
	* <li>start (Object) - Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator</li>
	* <li>decider (Object) - Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator</li>
	* <li>id (String) - Indicate the pageContext attribute id to store the resultant subset iterator in</li>
	* </ul>
	* <!-- END SNIPPET: params -->
	*
	*
	* <pre>
	* <!-- START SNIPPET: action -->
	* public class MySubsetTagAction extends ActionSupport {
	* public String execute() throws Exception {
	* l = new ArrayList();
	* l.add(new Integer(1));
	* l.add(new Integer(2));
	* l.add(new Integer(3));
	* l.add(new Integer(4));
	* l.add(new Integer(5));
	* return "done";
	* }
	*
	*
	* public Integer[] getMyArray() {
	* return a;
	* }
	*
	* public List getMyList() {
	* return l;
	* }
	*
	* public Decider getMyDecider() {
	* return new Decider() {
	* public boolean decide(Object element) throws Exception {
	* int i = ((Integer)element).intValue();
	* return (((i % 2) == 0)?true:false);
	* }
	* };
	* }
	* }
	* <!-- END SNIPPET: action -->
	* </pre>
	*
	*
	* <pre>
	* <!-- START SNIPPET: example1 -->
	* <!-- s: List basic -->
	* <s:subset source="myList">
	* <s:iterator>
	* <s:property />
	* </s:iterator>
	* </s:subset>
	* <!-- END SNIPPET: example1 -->
	* </pre>
	*
	* <pre>
	* <!-- START SNIPPET: example2 -->
	* <!-- B: List with count -->
	* <s:subset source="myList" count="3">
	* <s:iterator>
	* <s:property />
	* </s:iterator>
	* </s:subset>
	* <!-- END SNIPPET: example2 -->
	* </pre>
	*
	* <pre>
	* <!-- START SNIPPET: example3 -->
	* <!-- C: List with start -->
	* <s:subset source="myList" count="13" start="3">
	* <s:iterator>
	* <s:property />
	* </s:iterator>
	* </s:subset>
	* <!-- END SNIPPET: example3 -->
	* </pre>
	*
	* <pre>
	* <!-- START SNIPPET: example4 -->
	* <!-- D: List with id -->
	* <s:subset id="mySubset" source="myList" count="13" start="3" />
	* <%
	* Iterator i = (Iterator) pageContext.getAttribute("mySubset");
	* while(i.hasNext()) {
	* %>
	* <%=i.next() %>
	* <% } %>
	* <!-- END SNIPPET: example4 -->
	* </pre>
	*
	* <pre>
	* <!-- START SNIPPET: example5 -->
	* <!-- D: List with Decider -->
	* <s:subset source="myList" decider="myDecider">
	* <s:iterator>
	* <s:property />
	* </s:iterator>
	* </s:subset>
	* <!-- END SNIPPET: example5 -->
	* </pre>
	*
	*
	* @s.tag name="subset" tld-body-content="JSP"
	* description="Takes an iterator and outputs a subset of it"
	*/
	public class SubsetIteratorTag extends StrutsBodyTagSupport {

	private static final long serialVersionUID = -6252696081713080102L;

	private static final Log _log = LogFactory.getLog(SubsetIteratorTag.class);

	String countAttr;
	String sourceAttr;
	String startAttr;
	String deciderAttr;

	SubsetIteratorFilter subsetIteratorFilter = null;


	/**
	* @s.tagattribute required="false" type="Integer"
	* description="Indicate the number of entries to be in the resulting subset iterator"
	*/
	public void setCount(String count) {
	countAttr = count;
	}

	/**
	* @s.tagattribute required="false"
	* description="Indicate the source of which the resulting subset iterator is to be derived base on"
	*/
	public void setSource(String source) {
	sourceAttr = source;
	}

	/**
	* @s.tagattribute required="false" type="Integer"
	* description="Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator"
	*/
	public void setStart(String start) {
	startAttr = start;
	}

	/**
	* @s.tagattribute required="false" type="org.apache.struts2.util.SubsetIteratorFilter.Decider"
	* description="Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator"
	*/
	public void setDecider(String decider) {
	deciderAttr = decider;
	}


	public int doStartTag() throws JspException {

	// source
	Object source = null;
	if (sourceAttr == null && sourceAttr.length() <= 0) {
	source = findValue("top");
	} else {
	source = findValue(sourceAttr);
	}

	// count
	int count = -1;
	if (countAttr != null && countAttr.length() > 0) {
	Object countObj = findValue(countAttr);
	if (countObj instanceof Integer) {
	count = ((Integer)countObj).intValue();
	}
	else if (countObj instanceof Float) {
	count = ((Float)countObj).intValue();
	}
	else if (countObj instanceof Long) {
	count = ((Long)countObj).intValue();
	}
	else if (countObj instanceof Double) {
	count = ((Long)countObj).intValue();
	}
	else if (countObj instanceof String) {
	try {
	count = Integer.parseInt((String)countObj);
	}
	catch(NumberFormatException e) {
	_log.warn("unable to convert count attribute ["+countObj+"] to number, ignore count attribute", e);
	}
	}
	}

	// start
	int start = 0;
	if (startAttr != null && startAttr.length() > 0) {
	Object startObj = findValue(startAttr);
	if (startObj instanceof Integer) {
	start = ((Integer)startObj).intValue();
	}
	else if (startObj instanceof Float) {
	start = ((Float)startObj).intValue();
	}
	else if (startObj instanceof Long) {
	start = ((Long)startObj).intValue();
	}
	else if (startObj instanceof Double) {
	start = ((Long)startObj).intValue();
	}
	else if (startObj instanceof String) {
	try {
	start = Integer.parseInt((String)startObj);
	}
	catch(NumberFormatException e) {
	_log.warn("unable to convert count attribute ["+startObj+"] to number, ignore count attribute", e);
	}
	}
	}

	// decider
	Decider decider = null;
	if (deciderAttr != null && deciderAttr.length() > 0) {
	Object deciderObj = findValue(deciderAttr);
	if (! (deciderObj instanceof Decider)) {
	throw new JspException("decider found from stack ["+deciderObj+"] does not implement "+Decider.class);
	}
	decider = (Decider) deciderObj;
	}


	subsetIteratorFilter = new SubsetIteratorFilter();
	subsetIteratorFilter.setCount(count);
	subsetIteratorFilter.setDecider(decider);
	subsetIteratorFilter.setSource(source);
	subsetIteratorFilter.setStart(start);
	subsetIteratorFilter.execute();

	getStack().push(subsetIteratorFilter);
	if (getId() != null) {
	pageContext.setAttribute(getId(), subsetIteratorFilter);
	}

	return EVAL_BODY_INCLUDE;
	}

	public int doEndTag() throws JspException {

	getStack().pop();

	subsetIteratorFilter = null;

	return EVAL_PAGE;
	}
	}