Package org.apache.taglibs.standard.tag.common.core

Source Code of org.apache.taglibs.standard.tag.common.core.ParamSupport$ParamManager

/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License").  You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt.  If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
* own identifying information: Portions Copyright [yyyy]
* [name of copyright owner]
*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
*
* Portions Copyright Apache Software Foundation.
*/

package org.apache.taglibs.standard.tag.common.core;

import java.util.LinkedList;
import java.util.List;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.tagext.Tag;

import org.apache.taglibs.standard.resources.Resources;

/**
* <p>Support for tag handlers for &lt;param&gt;, the URL parameter
* subtag for &lt;import&gt; in JSTL 1.0.</p>
*
* @see ParamParent, ImportSupport, URLEncodeSupport
* @author Shawn Bayern
*/

public abstract class ParamSupport extends BodyTagSupport {

    //*********************************************************************
    // Protected state

    protected String name;                       // 'name' attribute
    protected String value;                      // 'value' attribute

    /**
     * There used to be an 'encode' attribute; I've left this as a
     * vestige in case custom subclasses want to use our functionality
     * but NOT encode parameters.
     */
    protected boolean encode = true;

    //*********************************************************************
    // Constructor and initialization

    public ParamSupport() {
  super();
  init();
    }

    private void init() {
  name = value = null;
    }

    //*********************************************************************
    // Tag logic

    // simply send our name and value to our appropriate ancestor
    public int doEndTag() throws JspException {
  Tag t = findAncestorWithClass(this, ParamParent.class);
  if (t == null)
      throw new JspTagException(
    Resources.getMessage("PARAM_OUTSIDE_PARENT"));

  // take no action for null or empty names
  if (name == null || name.equals(""))
      return EVAL_PAGE;

  // send the parameter to the appropriate ancestor
  ParamParent parent = (ParamParent) t;
  String value = this.value;
  if (value == null) {
      if (bodyContent == null || bodyContent.getString() == null)
    value = "";
      else
    value = bodyContent.getString().trim();
  }
        if (encode) {
            // FIXME: revert to java.net.URLEncoder.encode(s, enc) once
            // we have a dependency on J2SE 1.4+.
            String enc = pageContext.getResponse().getCharacterEncoding();
            parent.addParameter(
            Util.URLEncode(name, enc), Util.URLEncode(value, enc));
        } else {
            parent.addParameter(name, value);
        }
  return EVAL_PAGE;
    }

    // Releases any resources we may have (or inherit)
    public void release() {
  init();
    }

    //*********************************************************************
    // Support for parameter management

    /**
     * Provides support for aggregating query parameters in URLs.
     * Specifically, accepts a series of parameters, ensuring that
     *  - newer parameters will precede older ones in the output URL
     *  - all supplied parameters precede those in the input URL
     */
    public static class ParamManager {

        //*********************************
        // Private state

  private List names = new LinkedList();
        private List values = new LinkedList();
  private boolean done = false;
       
  //*********************************
        // Public interface

  /** Adds a new parameter to the list. */
        public void addParameter(String name, String value) {
      if (done)
    throw new IllegalStateException();
      if (name != null) {
          names.add(name);
          if (value != null)
        values.add(value);
          else
        values.add("");
      }
  }

  /**
         * Produces a new URL with the stored parameters, in the appropriate
         * order.
         */
  public String aggregateParams(String url) {
      /*
             * Since for efficiency we're destructive to the param lists,
             * we don't want to run multiple times.
             */
      if (done)
    throw new IllegalStateException();
      done = true;

      //// reverse the order of our two lists
      // Collections.reverse(this.names);
      // Collections.reverse(this.values);

      // build a string from the parameter list
      StringBuffer newParams = new StringBuffer();
      for (int i = 0; i < names.size(); i++) {
    newParams.append(names.get(i) + "=" + values.get(i));
    if (i < (names.size() - 1))
        newParams.append("&");
      }

      // insert these parameters into the URL as appropriate
      if (newParams.length() > 0) {
          int questionMark = url.indexOf('?');
          if (questionMark == -1) {
        return (url + "?" + newParams);
          } else {
        StringBuffer workingUrl = new StringBuffer(url);
        workingUrl.insert(questionMark + 1, (newParams + "&"));
        return workingUrl.toString();
          }
      } else {
    return url;
      }
  }
    }
}
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