Java tutorial
package com.cognifide.slice.cq.taglib; /* * #%L * Slice - CQ Taglib * $Id:$ * $HeadURL:$ * %% * Copyright (C) 2012 Cognifide Limited * %% * 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. * #L% */ import java.io.IOException; import java.io.Writer; import javax.servlet.jsp.JspTagException; import javax.servlet.jsp.JspWriter; import org.apache.commons.lang.StringUtils; import com.cognifide.slice.api.link.LinkExternalizer; import com.cognifide.slice.commons.link.LinkBuilderImpl; import com.cognifide.slice.commons.link.LinkExternalizerImpl; /** * Renders HTML anchor but does not render empty attributes. In other words, the tag can have attribute * defined, but if it's value is empty, it will not be rendered. * * Additionally, this tag supports externalisation of handles passed in a href attribute. * * @author Albert Cenkier * @author Jan Kuniak */ public class AnchorTag extends AbstractBodyTag { private static final long serialVersionUID = 2811258272922488176L; /** id attribute of the <tt><a></tt> tag - specifies a unique id for an element */ private String id; /** class attribute of the <tt><a></tt> tag - specifies a class name for an element */ private String clazz; /** title attribute of the <tt><a></tt> tag - specifies extra information about an element */ private String title; /** target attribute of the <tt><a></tt> tag - specifies where to open the linked document */ private String target; /** name attribute of the <tt><a></tt> tag - specifies the name of an anchor */ private String name; /** * rel attribute of the <tt><a></tt> tag - specifies the relationship between the current document * and the linked document */ private String rel; /** onclick attribute of the <tt><a></tt> tag - script to be run on a mouse click */ private String onclick; /** href attribute of the <tt><a></tt> tag - specifies the destination of a link */ private String href; /** specifies extension to be used when externalising if a handle was passed as href */ private String extension; /** specifies selector to be used when externalising if a handle was passed as href */ private String selector; /** if true - the href value will be externalised */ private boolean externalise = true; /** * Appends attribute to a writer if attribute's value is not blank. The attribute is appended in a format: * <tt>' attributeName="attributeValue"'</tt> (with a leading space and double quotes). * * @param out output stream to append the attribute to * @param attributeName name of the attribute to be appended * @param attributeValue value of the attribute * @throws IOException if an I/O error occurs. */ protected void apppendAttributeIfNotBlank(Writer out, String attributeName, String attributeValue) throws IOException { if (StringUtils.isNotBlank(attributeValue)) { out.append(" ").append(attributeName).append("=\"").append(attributeValue).append("\""); } } /** {@inheritDoc} */ @Override public int doStartTag() throws JspTagException { if (isRender()) { try { String link = this.href; if (externalise) { final LinkBuilderImpl linkBuilder = new LinkBuilderImpl(); linkBuilder.setPath(link); linkBuilder.setSelectorString(selector); linkBuilder.setExtension(extension); final LinkExternalizer linkExternalizer = new LinkExternalizerImpl(null); link = linkExternalizer.externalizeLink(linkBuilder.toLink()).toString(); } JspWriter out = getJspWriter(); out.append("<a"); apppendAttributeIfNotBlank(out, "href", link); apppendAttributeIfNotBlank(out, "id", id); apppendAttributeIfNotBlank(out, "class", clazz); apppendAttributeIfNotBlank(out, "title", title); apppendAttributeIfNotBlank(out, "target", target); apppendAttributeIfNotBlank(out, "name", name); apppendAttributeIfNotBlank(out, "rel", rel); apppendAttributeIfNotBlank(out, "onclick", onclick); out.append(">"); } catch (IOException e) { // should never occur logger.error("unexpected exception occured", e); } } return EVAL_BODY_INCLUDE; } /** {@inheritDoc} */ @Override public int doEndTag() throws JspTagException { if (isRender()) { try { getJspWriter().append("</a>"); } catch (IOException e) { logger.error("unexpected exception occured", e); } } return EVAL_PAGE; } // ///////////////////////////////////////////////////////////////////////// // getters and setters // /////////////////////////////////////////////////////////////////////// /** @return the id */ @Override public String getId() { return id; } /** @param id the id to set */ @Override public void setId(String id) { this.id = id; } /** @return the clazz */ public String getClazz() { return clazz; } /** @param clazz the clazz to set */ public void setClazz(String clazz) { this.clazz = clazz; } /** @return the title */ public String getTitle() { return title; } /** @param title the title to set */ public void setTitle(String title) { this.title = title; } /** @return the target */ public String getTarget() { return target; } /** @param target the target to set */ public void setTarget(String target) { this.target = target; } /** @return the name */ public String getName() { return name; } /** @param name the name to set */ public void setName(String name) { this.name = name; } /** @return the rel */ public String getRel() { return rel; } /** @param rel the rel to set */ public void setRel(String rel) { this.rel = rel; } /** @return the onclick */ public String getOnclick() { return onclick; } /** @param onclick the onclick to set */ public void setOnclick(String onclick) { this.onclick = onclick; } /** @return the href */ public String getHref() { return href; } /** @param href the href to set */ public void setHref(String href) { this.href = href; } /** @return the extension */ public String getExtension() { return extension; } /** @param extension the extension to set */ public void setExtension(String extension) { this.extension = extension; } /** @return the selector */ public String getSelector() { return selector; } /** @param selector the selector to set */ public void setSelector(String selector) { this.selector = selector; } /** @return the externalise */ public boolean isExternalise() { return externalise; } /** @param externalise the externalise to set */ public void setExternalise(boolean externalise) { this.externalise = externalise; } }