org.springframework.web.servlet.tags.form.AbstractCheckedElementTag Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* 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
*
* https://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.springframework.web.servlet.tags.form;
import javax.servlet.jsp.JspException;
import org.springframework.lang.Nullable;
/**
* Abstract base class to provide common methods for
* implementing databinding-aware JSP tags for rendering an HTML '{@code input}'
* element with a '{@code type}' of '{@code checkbox}' or '{@code radio}'.
*
* @author Thomas Risberg
* @author Juergen Hoeller
* @author Rossen Stoyanchev
* @since 2.5
*/
@SuppressWarnings("serial")
public abstract class AbstractCheckedElementTag extends AbstractHtmlInputElementTag {
/**
* Render the '{@code input(checkbox)}' with the supplied value, marking the
* '{@code input}' element as 'checked' if the supplied value matches the
* bound value.
*/
protected void renderFromValue(@Nullable Object value, TagWriter tagWriter) throws JspException {
renderFromValue(value, value, tagWriter);
}
/**
* Render the '{@code input(checkbox)}' with the supplied value, marking the
* '{@code input}' element as 'checked' if the supplied value matches the
* bound value.
*/
protected void renderFromValue(@Nullable Object item, @Nullable Object value, TagWriter tagWriter)
throws JspException {
String displayValue = convertToDisplayString(value);
tagWriter.writeAttribute("value", processFieldValue(getName(), displayValue, getInputType()));
if (isOptionSelected(value) || (value != item && isOptionSelected(item))) {
tagWriter.writeAttribute("checked", "checked");
}
}
/**
* Determines whether the supplied value matched the selected value
* through delegating to {@link SelectedValueComparator#isSelected}.
*/
private boolean isOptionSelected(@Nullable Object value) throws JspException {
return SelectedValueComparator.isSelected(getBindStatus(), value);
}
/**
* Render the '{@code input(checkbox)}' with the supplied value, marking
* the '{@code input}' element as 'checked' if the supplied Boolean is
* {@code true}.
*/
protected void renderFromBoolean(Boolean boundValue, TagWriter tagWriter) throws JspException {
tagWriter.writeAttribute("value", processFieldValue(getName(), "true", getInputType()));
if (boundValue) {
tagWriter.writeAttribute("checked", "checked");
}
}
/**
* Return a unique ID for the bound name within the current PageContext.
*/
@Override
@Nullable
protected String autogenerateId() throws JspException {
String id = super.autogenerateId();
return (id != null ? TagIdGenerator.nextId(id, this.pageContext) : null);
}
/**
* Writes the '{@code input}' element to the supplied
* {@link TagWriter},
* marking it as 'checked' if appropriate.
*/
@Override
protected abstract int writeTagContent(TagWriter tagWriter) throws JspException;
/**
* Flags "type" as an illegal dynamic attribute.
*/
@Override
protected boolean isValidDynamicAttribute(String localName, Object value) {
return !"type".equals(localName);
}
/**
* Return the type of the HTML input element to generate:
* "checkbox" or "radio".
*/
protected abstract String getInputType();
}