pagerrenderer.java

我自己写的一个大批量数据分页软件,和大家交流交流

package cn.org.ccs.ccse.pager;


import java.io.IOException;
import java.util.Map;
import javax.faces.component.UIComponent;
import javax.faces.component.UIData;
import javax.faces.component.UIForm;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.el.ValueBinding;
import javax.faces.render.Renderer;

public class PagerRenderer extends Renderer {
	private int first;
	private int itemcount;
	public void encodeBegin(FacesContext context, UIComponent component)
			throws IOException {
		int leftspacing;
		int centerspacing;
		int rightspacing;
		String id = component.getClientId(context);
		UIComponent parent = component;
		while (!(parent instanceof UIForm))
			parent = parent.getParent();
		String formId = parent.getClientId(context);
		UIComponent comp = component;
		while (!(comp instanceof UIData))
			comp = comp.getParent();
		comp = (UIData)comp;
		ResponseWriter writer = context.getResponseWriter();
		String imgFirst = (String) get(context, component, "imgFirst");
		String imgNext = (String) get(context, component, "imgNext");
		String imgLast = (String) get(context, component, "imgLast");
		String imgBefore = (String) get(context, component, "imgBefore");
		String imgFirstHidden = (String) get(context, component, "imgFirstHidden");
		String imgNextHidden = (String) get(context, component, "imgNextHidden");
		String imgLastHidden = (String) get(context, component, "imgLastHidden");
		String imgBeforeHidden = (String) get(context, component, "imgBeforeHidden");
		Integer itemcounts = (Integer) get(context, component, "itemcount");
		if (itemcounts != null)
			itemcount = Integer.valueOf(itemcounts);
		else
			itemcount = 0;
		Integer leftspacings = (Integer) get(context, component, "leftspacing");
		if (leftspacings != null)
			leftspacing = Integer.valueOf(leftspacings);
		else
			leftspacing = 0;
		Integer centerspacings = (Integer) get(context, component, "centerspacing");
		if (centerspacings != null)
			centerspacing = Integer.valueOf(centerspacings);
		else
			centerspacing = 0;
		Integer rightspacings = (Integer) get(context, component, "rightspacing");
		if (rightspacings != null)
			rightspacing = Integer.valueOf(rightspacings);
		else
			rightspacing = 0;
		Integer firsts = (Integer) get(context, component, "first");
		if (firsts != null)
			first = firsts.intValue();
		else
			first = 0;
		Integer a = (Integer) get(context, component, "showpages");
		int showpages;
		if (a == null) {
			showpages = 1;
		} else {
			showpages = a.intValue();
		}
		// find the component with the given ID
		int current = first / showpages + 1;
		if (showpages <= 0)
			showpages = itemcount;
		int pages = (itemcount - 1) / showpages + 1;
		writer.startElement("table", component);
		writer.startElement("tr", component);
		writePage(writer, component, pages, current,showpages,leftspacing,centerspacing);
		if (first == 0) {
			if (imgFirstHidden != null)
				writeLinkImgOver(writer, component, formId, id, "<", 
						imgFirstHidden);
			else
				writeLinkOver(writer, component, formId, id, "<",
						 "第一页");
			if (imgBeforeHidden != null)
				writeLinkImgOver(writer, component, formId, id, "<<",
						imgBeforeHidden);
			else
				writeLinkOver(writer, component, formId, id, "<<",
						 "上一页");
		} else {
			if (imgFirst != null)
				writeLinkImg(writer, component, formId, id, "<", 
						imgFirst);
			else
				writeLink(writer, component, formId, id, "<",
						"第一页");
			if (imgBefore != null)
				writeLinkImg(writer, component, formId, id, "<<",
						imgBefore);
			else
				writeLink(writer, component, formId, id, "<<", 
						"上一页");
		}
		if (first + showpages >= itemcount) {
			if (imgNextHidden != null)
				writeLinkImgOver(writer, component, formId, id, ">>", 
						imgNextHidden);
			else
				writeLinkOver(writer, component, formId, id, ">>",
						 "下一页");
			if (imgLastHidden != null)
				writeLinkImgOver(writer, component, formId, id, ">",
						imgLastHidden);
			else
				writeLinkOver(writer, component, formId, id, ">",
						 "最后一页");
		} else {
			if (imgNext != null)
				writeLinkImg(writer, component, formId, id, ">>",
						imgNext);
			else
				writeLink(writer, component, formId, id, ">>",
						"下一页");
			if (imgLast != null)
				writeLinkImg(writer, component, formId, id, ">", 
						imgLast);
			else
				writeLink(writer, component, formId, id, ">",
						"最后一页");
		}
		writeLinkSelect(writer, component, formId, id,
				pages, showpages);
		// hidden field to hold result
		writeHiddenField(writer, component, id);
		writer.startElement("td", component);
		writer.writeAttribute("width", rightspacing+"px", null);
		writer.endElement("td");
		writer.endElement("tr");
		writer.endElement("table");
	}

	private void writeLink(ResponseWriter writer, UIComponent component,
			String formId, String id, String value, 
			String text) throws IOException {
		writer.startElement("td", null);
		writer.writeAttribute("align", "right", null);
		writer.writeAttribute("valign", "middle", null);
		writer.writeAttribute("width", "80px", null);
		writer.startElement("a", component);
		writer.writeAttribute("href", "#", null);
		writer.writeAttribute("onclick", onclickCode(formId, id, value), null);
		writer.startElement("font", component);
		writer.writeAttribute("size", "2", null);
		writer.writeText(text, null);
		writer.endElement("font");
		writer.endElement("a");
		writer.endElement("td");
	}

	private void writeLinkOver(ResponseWriter writer, UIComponent component,
			String formId, String id, String value, 
			String text) throws IOException {
		writer.startElement("td", null);
		writer.writeAttribute("width", "80px", null);
		writer.writeAttribute("align", "right", null);
		writer.writeAttribute("valign", "middle", null);
		writer.startElement("font", component);
		writer.writeAttribute("size", "2", null);
		writer.writeText(text, null);
		writer.endElement("font");
		writer.endElement("td");
	}

	private void writeLinkImg(ResponseWriter writer, UIComponent component,
			String formId, String id, String value,
			String src) throws IOException {
		writer.startElement("td", null);
		writer.writeAttribute("align", "right", null);
		writer.writeAttribute("width", "15px", null);
		writer.writeText(" ", null);
		writer.writeText(" ", null);
		writer.startElement("a", component);
		writer.writeAttribute("href", "#", null);
		writer.writeAttribute("onclick", onclickCode(formId, id, value), null);
		writer.startElement("img", null);
		//writer.writeAttribute("onmouseout",
			//	"event.srcElement.style.border=\"0px\"", null);
		//writer.writeAttribute("onmouseover",
			//	"event.srcElement.style.border=\"1px solid #777777\"", null);
		writer.writeAttribute("border", "0", null);
		writer.writeAttribute("src", src, null);
		writer.endElement("a");
		writer.endElement("td");
	}

	private void writeLinkImgOver(ResponseWriter writer, UIComponent component,
			String formId, String id, String value,
			String src) throws IOException {
		writer.startElement("td", null);
		writer.writeAttribute("align", "right", null);
		writer.writeAttribute("width", "15px", null);
		writer.startElement("img", null);
		writer.writeAttribute("src", src, null);
		writer.endElement("td");
	}

	private void writeLinkSelect(ResponseWriter writer, UIComponent component,
			String formId, String id, int pages,
			int showpages) throws IOException {
		writer.startElement("td", component);
		writer.writeAttribute("align", "right", null);
		writer.startElement("select", component);
		String value = "";
		writer.writeAttribute("name", "selectName", null);
		writer.writeAttribute("onchange", onclickSelectCode(formId, id, null),
				"onchange");
		for (int i = 1; i < pages + 1; i++) {
			value = i + "";
			writer.startElement("font", component);
			writer.writeAttribute("size", 1, null);
			writer.startElement("option", component);
			writer.writeAttribute("value", value, null);
			if ((first / showpages + 1) == i)
				writer.writeAttribute("selected", "selected", null);
			
			writer.writeText("第" + value + "页", null);
			
			writer.endElement("option");
			writer.endElement("font");
		}
		writer.endElement("select");
		writer.endElement("td");
	}

	private String onclickCode(String formId, String id, String value) {
		StringBuffer buffer = new StringBuffer();
		buffer.append("document.forms['"+formId+"'].target='_self';");
		buffer.append("document.forms[");
		buffer.append("'");
		buffer.append(formId);
		buffer.append("'");
		buffer.append("]['");
		buffer.append(id);
		buffer.append("'].value='");
		buffer.append(value);
		buffer.append("';");
		buffer.append(" document.forms[");
		buffer.append("'");
		buffer.append(formId);
		buffer.append("'");
		buffer.append("].submit()");
		buffer.append("; return false;");
		return buffer.toString();
	}

	private String onclickSelectCode(String formId, String id, String value) {
		StringBuffer buffer = new StringBuffer();
		buffer.append("document.forms['"+formId+"'].target='_self';");
		buffer.append("document.forms[");
		buffer.append("'");
		buffer.append(formId);
		buffer.append("'");
		buffer.append("]['");
		buffer.append(id);
		buffer.append("'].value=");
		buffer.append("this.options[this.selectedIndex].value;");
		buffer.append(" document.forms[");
		buffer.append("'");
		buffer.append(formId);
		buffer.append("'");
		buffer.append("].submit();");
		buffer.append(" return false;");
		return buffer.toString();
	}

	private void writeHiddenField(ResponseWriter writer, UIComponent component,
			String id) throws IOException {
		writer.startElement("td", component);
		writer.startElement("input", component);
		writer.writeAttribute("type", "hidden", null);
		writer.writeAttribute("name", id, null);
		writer.endElement("input");
		writer.endElement("td");
	}

	private void writePage(ResponseWriter writer, UIComponent component,
			int pagesize, int currentPage,int showpages,int leftspacing,int centerspacing) throws IOException {
		writer.startElement("td", component);
		writer.writeAttribute("width", leftspacing+"px", null);
		writer.endElement("td");
		writer.startElement("td", component);
		writer.writeAttribute("width", "300px", null);
		writer.writeAttribute("align", "left", null);
		writer.writeAttribute("valign", "bottom", null);
		writer.startElement("font", component);
		writer.writeAttribute("size", "2", null);
		writer.writeText("共" + pagesize + "页", null);
		writer.writeText("        ",null);
		writer.writeText("第" + currentPage + "页", null);
		writer.writeText("           ",null);
		writer.writeText("共"+itemcount+"条", null);
		writer.writeText("     ", null);
		writer.writeText("每页"+showpages+"条", null);
		writer.endElement("font");
		writer.endElement("td");
		writer.startElement("td", component);
		writer.writeAttribute("width", centerspacing+"px", null);
		writer.endElement("td");
	}

	public void decode(FacesContext context, UIComponent component) {
		String id = component.getClientId(context);
		Map parameters = context.getExternalContext().getRequestParameterMap();
		String response = (String) parameters.get(id);
		Integer a = (Integer) get(context, component, "showpages");
		int showpages = 0;
		int pages=1;
		if (a != null) {
			showpages = a.intValue();
		}
		if (showpages <= 0)
			showpages = itemcount;
		if(showpages>0)
			pages = (itemcount - 1) / showpages + 1;
		if (response.equals("<"))
			first = 0;
		else if (response.equals(">"))
			first = (pages - 1) * showpages;
		else if (response.equals("<<"))
			first = first - showpages;
		else if (response.equals(">>"))
			first = first + showpages;
		else if(response==null||response.equals("")){
			
		}
		else {
			int page = Integer.parseInt(response);
			first = (page - 1) * showpages;
		}
		if (first + showpages > itemcount)
			first = (pages - 1) * showpages;
		if (first < 0)
			first = 0;
		ValueBinding vb = component.getValueBinding("first");
		vb.setValue(context, first);
	}

	private static Object get(FacesContext context, UIComponent component,
			String name) {
		ValueBinding binding = component.getValueBinding(name);
		if (binding != null)
			return binding.getValue(context);
		else
			return component.getAttributes().get(name);
	}
}