/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.wicket.markup.head;
import java.util.Collections;
import java.util.Map;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.request.Response;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.string.Strings;
import org.apache.wicket.util.value.ValueMap;
/**
* {@link HeaderItem} for meta informations such as <meta> tags or
* canonical <link>
*
* @author andrea del bene
* @since 6.17.0
*/
public class MetaDataHeaderItem extends HeaderItem
{
public static final String META_TAG = "meta";
public static final String LINK_TAG = "link";
private final Map<String, Object> tagAttributes;
private final String tagName;
/**
* Build a new {@link MetaDataHeaderItem} having {@code tagName} as tag.
*
* @param tagName
* the name of the tag
*/
public MetaDataHeaderItem(String tagName)
{
this.tagName = Args.notEmpty(tagName, "tagName");
this.tagAttributes = new ValueMap();
}
/**
* Add a tag attribute to the item. If the attribute value is a {@link IModel},
* the object wrapped inside the model is used as actual value.
*
* @param attributeName
* the attribute name
* @param attributeValue
* the attribute value
* @return
* The current item.
*/
public MetaDataHeaderItem addTagAttribute(String attributeName, Object attributeValue)
{
Args.notEmpty(attributeName, "attributeName");
Args.notNull(attributeValue, "attributeValue");
tagAttributes.put(attributeName, attributeValue);
return this;
}
/**
* Generate the string representation for the current item.
*
* @return
* The string representation for the current item.
*/
public String generateString()
{
StringBuilder buffer = new StringBuilder();
buffer.append('<').append(tagName);
for (Map.Entry<String, Object> entry : tagAttributes.entrySet())
{
Object value = entry.getValue();
if (value instanceof IModel)
{
value = ((IModel<?>)value).getObject();
}
if (value != null)
{
buffer.append(' ')
.append(Strings.escapeMarkup(entry.getKey()))
.append('=')
.append('"')
.append(Strings.escapeMarkup(value.toString()))
.append('"');
}
}
buffer.append(" />\n");
return buffer.toString();
}
@Override
public Iterable<?> getRenderTokens()
{
return Collections.singletonList(generateString());
}
@Override
public void render(Response response)
{
response.write(generateString());
}
/**
* Factory method to create <meta> tag.
*
* @param name
* the 'name' attribute of the tag
* @param content
* the 'content' attribute of the tag
* @return
* A new {@link MetaDataHeaderItem}
*/
public static MetaDataHeaderItem forMetaTag(String name, String content)
{
return forMetaTag(Model.of(name), Model.of(content));
}
/**
* Factory method to create <meta> tag.
*
* @param name
* the 'name' attribute of the tag as String model
* @param content
* the 'content' attribute of the tag as String model
* @return
* A new {@link MetaDataHeaderItem}
*/
public static MetaDataHeaderItem forMetaTag(IModel<String> name, IModel<String> content)
{
MetaDataHeaderItem headerItem = new MetaDataHeaderItem(META_TAG);
headerItem.addTagAttribute("name", name);
headerItem.addTagAttribute("content", content);
return headerItem;
}
/**
* Factory method to create <link> tag.
*
* @param rel
* the 'rel' attribute of the tag
* @param href
* the 'href' attribute of the tag
* @return
* A new {@link MetaDataHeaderItem}
*/
public static MetaDataHeaderItem forLinkTag(String rel, String href)
{
return forLinkTag(Model.of(rel), Model.of(href));
}
/**
* Factory method to create <link> tag.
*
* @param rel
* the 'rel' attribute of the tag as String model
* @param href
* the 'href' attribute of the tag as String model
* @return
* A new {@link MetaDataHeaderItem}
*/
public static MetaDataHeaderItem forLinkTag(IModel<String> rel, IModel<String> href)
{
MetaDataHeaderItem headerItem = new MetaDataHeaderItem(LINK_TAG);
headerItem.addTagAttribute("rel", rel);
headerItem.addTagAttribute("href", href);
return headerItem;
}
@Override
public boolean equals(Object obj)
{
return obj instanceof MetaDataHeaderItem && ((MetaDataHeaderItem) obj).generateString().equals(generateString());
}
@Override
public int hashCode()
{
return generateString().hashCode();
}
}