columntag.java

一个比较不错的java分页标签,有源代码,开发者 可以学习学习

/**
 * Licensed under the Artistic License; you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://displaytag.sourceforge.net/license.html
 *
 * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */
package org.displaytag.tags;

import java.text.Collator;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.displaytag.decorator.AutolinkColumnDecorator;
import org.displaytag.decorator.DisplaytagColumnDecorator;
import org.displaytag.decorator.EscapeXmlColumnDecorator;
import org.displaytag.decorator.MessageFormatColumnDecorator;
import org.displaytag.exception.DecoratorInstantiationException;
import org.displaytag.exception.InvalidTagAttributeValueException;
import org.displaytag.exception.ObjectLookupException;
import org.displaytag.exception.TagStructureException;
import org.displaytag.model.Cell;
import org.displaytag.model.DefaultComparator;
import org.displaytag.model.HeaderCell;
import org.displaytag.properties.MediaTypeEnum;
import org.displaytag.properties.SortOrderEnum;
import org.displaytag.util.DefaultHref;
import org.displaytag.util.Href;
import org.displaytag.util.HtmlAttributeMap;
import org.displaytag.util.MediaUtil;
import org.displaytag.util.MultipleHtmlAttribute;
import org.displaytag.util.TagConstants;


/**
 * <p>
 * This tag works hand in hand with the TableTag to display a list of objects. This describes a column of data in the
 * TableTag. There can be any number of columns that make up the list.
 * </p>
 * <p>
 * This tag does no work itself, it is simply a container of information. The TableTag does all the work based on the
 * information provided in the attributes of this tag.
 * <p>
 * @author mraible
 * @author Fabrizio Giustina
 * @version $Revision: 1008 $ ($Author: fgiust $)
 */
public class ColumnTag extends BodyTagSupport implements MediaUtil.SupportsMedia
{

    /**
     * D1597A17A6.
     */
    private static final long serialVersionUID = 899149338534L;

    /**
     * logger.
     */
    private static Log log = LogFactory.getLog(ColumnTag.class);

    /**
     * html pass-through attributes for cells.
     */
    private HtmlAttributeMap attributeMap = new HtmlAttributeMap();

    /**
     * html pass-through attributes for cell headers.
     */
    private HtmlAttributeMap headerAttributeMap = new HtmlAttributeMap();

    /**
     * the property method that is called to retrieve the information to be displayed in this column. This method is
     * called on the current object in the iteration for the given row. The property format is in typical struts format
     * for properties (required)
     */
    private String property;

    /**
     * the title displayed for this column. if this is omitted then the property name is used for the title of the
     * column (optional).
     */
    private String title;

    /**
     * by default, null values don't appear in the list, by setting viewNulls to 'true', then null values will appear as
     * "null" in the list (mostly useful for debugging) (optional).
     */
    private boolean nulls;

    /**
     * is the column sortable?
     */
    private boolean sortable;

    /**
     * Name given to the server when sorting this column.
     */
    private String sortName;

    /**
     * Defalt sort order for this column.
     */
    private SortOrderEnum defaultorder;

    /**
     * The comparator to use when sorting this column.
     */
    private Comparator comparator;

    /**
     * if set to true, then any email addresses and URLs found in the content of the column are automatically converted
     * into a hypertext link.
     */
    private boolean autolink;

    /**
     * Automatically escape column content for html and xml media.
     */
    private boolean escapeXml;

    /**
     * A MessageFormat patter that will be used to decorate objects in the column. Can be used as a "shortcut" for
     * simple column decorations.
     */
    private String format;

    /**
     * the grouping level (starting at 1 and incrementing) of this column (indicates if successive contain the same
     * values, then they should not be displayed). The level indicates that if a lower level no longer matches, then the
     * matching for this higher level should start over as well. If this attribute is not included, then no grouping is
     * performed. (optional)
     */
    private int group = -1;

    /**
     * if this attribute is provided, then the data that is shown for this column is wrapped inside a &lt;a href&gt; tag
     * with the url provided through this attribute. Typically you would use this attribute along with one of the
     * struts-like param attributes below to create a dynamic link so that each row creates a different URL based on the
     * data that is being viewed. (optional)
     */
    private Href href;

    /**
     * The name of the request parameter that will be dynamically added to the generated href URL. The corresponding
     * value is defined by the paramProperty and (optional) paramName attributes, optionally scoped by the paramScope
     * attribute. (optional)
     */
    private String paramId;

    /**
     * The name of a JSP bean that is a String containing the value for the request parameter named by paramId (if
     * paramProperty is not specified), or a JSP bean whose property getter is called to return a String (if
     * paramProperty is specified). The JSP bean is constrained to the bean scope specified by the paramScope property,
     * if it is specified. If paramName is omitted, then it is assumed that the current object being iterated on is the
     * target bean. (optional)
     */
    private String paramName;

    /**
     * The name of a property of the bean specified by the paramName attribute (or the current object being iterated on
     * if paramName is not provided), whose return value must be a String containing the value of the request parameter
     * (named by the paramId attribute) that will be dynamically added to this href URL. (optional)
     * @deprecated use Expressions in paramName
     */
    private String paramProperty;

    /**
     * The scope within which to search for the bean specified by the paramName attribute. If not specified, all scopes
     * are searched. If paramName is not provided, then the current object being iterated on is assumed to be the target
     * bean. (optional)
     * @deprecated use Expressions in paramName
     */
    private String paramScope;

    /**
     * If this attribute is provided, then the column's displayed is limited to this number of characters. An elipse
     * (...) is appended to the end if this column is linked, and the user can mouseover the elipse to get the full
     * text. (optional)
     */
    private int maxLength;

    /**
     * If this attribute is provided, then the column's displayed is limited to this number of words. An elipse (...) is
     * appended to the end if this column is linked, and the user can mouseover the elipse to get the full text.
     * (optional)
     */
    private int maxWords;

    /**
     * a class that should be used to "decorate" the underlying object being displayed. If a decorator is specified for
     * the entire table, then this decorator will decorate that decorator. (optional)
     */
    private String decorator;

    /**
     * is the column already sorted?
     */
    private boolean alreadySorted;

    /**
     * The media supported attribute.
     */
    private List supportedMedia;

    /**
     * Property in a resource bundle to be used as the title for the column.
     */
    private String titleKey;

    /**
     * The name of the bean property if a decorator is used and sorting need to be still on on the property itself.
     * Useful for displaying data with links but sorting on original value.
     */
    private String sortProperty;

    /**
     * Should the value of the column be summed? Requires that the value of the column be convertible to a Number.
     */
    private boolean totaled;

    /**
     * Static value for this cell, equivalent to column body.
     */
    private Object value;

    /**
     * Setter for totals.
     * @param totals the value
     */
    public void setTotal(boolean totals)
    {
        this.totaled = totals;
    }

    /**
     * setter for the "property" tag attribute.
     * @param value attribute value
     */
    public void setProperty(String value)
    {
        this.property = value;
    }

    /**
     * setter for the "value" tag attribute.
     * @param value attribute value
     */
    public void setValue(Object value)
    {
        this.value = value;
    }

    /**
     * Set the comparator, classname or object.
     * @param comparatorObj the comparator, classname or object
     */
    public void setComparator(Object comparatorObj)
    {
        // @todo don't do this! Setters should remains simple setters and any evaluation should be done in doEndTag()!
        if (comparatorObj instanceof Comparator)
        {
            this.comparator = (Comparator) comparatorObj;
        }
        else if (comparatorObj instanceof String)
        {
            String comparatorClassname = (String) comparatorObj;
            Class compClass;
            try
            {
                compClass = Thread.currentThread().getContextClassLoader().loadClass(comparatorClassname);
            }
            catch (ClassNotFoundException e)
            {
                throw new RuntimeException("InstantiationException setting column comparator as "
                    + comparatorClassname
                    + ": "
                    + e.getMessage(), e);
            }
            try
            {
                this.comparator = (Comparator) compClass.newInstance();
            }
            catch (InstantiationException e)
            {
                throw new RuntimeException("InstantiationException setting column comparator as "
                    + comparatorClassname
                    + ": "
                    + e.getMessage(), e);
            }
            catch (IllegalAccessException e)
            {
                throw new RuntimeException("IllegalAccessException setting column comparator as "
                    + comparatorClassname
                    + ": "
                    + e.getMessage(), e);
            }
        }
        else
        {
            throw new IllegalArgumentException("Value for comparator: "
                + comparatorObj
                + " of type "
                + comparatorObj.getClass().getName());
        }
    }

    /**
     * setter for the "title" tag attribute.
     * @param value attribute value
     */
    public void setTitle(String value)
    {
        this.title = value;
    }

    /**
     * setter for the "format" tag attribute.
     * @param value attribute value
     */
    public void setFormat(String value)
    {
        this.format = value;
    }

    /**
     * setter for the "nulls" tag attribute.
     * @param value attribute value
     */
    public void setNulls(boolean value)
    {
        this.nulls = value;
    }

    /**
     * setter for the "sortable" tag attribute.
     * @param value attribute value
     */
    public void setSortable(boolean value)
    {
        this.sortable = value;
    }

    /**
     * setter for the "autolink" tag attribute.
     * @param value attribute value
     */
    public void setAutolink(boolean value)
    {
        this.autolink = value;
    }

    /**
     * setter for the "escapeXml" tag attribute.
     * @param value attribute value
     */
    public void setEscapeXml(boolean value)
    {
        this.escapeXml = value;
    }

    /**
     * setter for the "group" tag attribute.
     * @param value attribute value
     */
    public void setGroup(int value)
    {
        this.group = value;
    }

    /**
     * setter for the "titleKey" tag attribute.
     * @param value property name
     */
    public void setTitleKey(String value)
    {
        this.titleKey = value;
    }

    /**
     * setter for the "href" tag attribute.
     * @param value attribute value
     */
    public void setHref(String value)
    {
        // call encodeURL to preserve session id when cookies are disabled
        String encodedHref = ((HttpServletResponse) this.pageContext.getResponse()).encodeURL(StringUtils
            .defaultString(value));
        this.href = new DefaultHref(encodedHref);
    }

    /**
     * setter for the "url" tag attribute. This has the same meaning of href, but prepends the context path to the given
     * URI.
     * @param value attribute value
     */
    public void setUrl(String value)
    {
        HttpServletRequest req = (HttpServletRequest) pageContext.getRequest();
        // call encodeURL to preserve session id when cookies are disabled
        String encodedHref = ((HttpServletResponse) this.pageContext.getResponse()).encodeURL(StringUtils
            .defaultString(req.getContextPath() + value));
        this.href = new DefaultHref(encodedHref);
    }

    /**
     * setter for the "paramId" tag attribute.
     * @param value attribute value
     */
    public void setParamId(String value)
    {
        this.paramId = value;
    }

    /**
     * setter for the "paramName" tag attribute.
     * @param value attribute value
     */
    public void setParamName(String value)
    {
        this.paramName = value;
    }

    /**
     * setter for the "paramProperty" tag attribute.
     * @param value attribute value
     */
    public void setParamProperty(String value)
    {
        this.paramProperty = value;
    }

    /**
     * setter for the "paramScope" tag attribute.
     * @param value attribute value
     */
    public void setParamScope(String value)
    {
        this.paramScope = value;
    }