org.springframework.web.servlet.tags.form.CheckboxTag Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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
*
* 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.springframework.web.servlet.tags.form;
import java.util.Collection;
import javax.servlet.jsp.JspException;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.web.bind.WebDataBinder;
/**
* Databinding-aware JSP tag for rendering an HTML 'input'
* element with a 'type' of 'checkbox'.
*
* May be used in one of three different approaches depending on the
* type of the {@link #getValue bound value}.
*
*
Approach One
* When the bound value is of type {@link Boolean} then the 'input(checkbox)'
* is marked as 'checked' if the bound value is true. The 'value'
* attribute corresponds to the resolved value of the {@link #setValue(Object) value} property.
* Approach Two
* When the bound value is of type {@link Collection} then the 'input(checkbox)'
* is marked as 'checked' if the configured {@link #setValue(Object) value} is present in
* the bound {@link Collection}.
* Approach Three
* For any other bound value type, the 'input(checkbox)' is marked as 'checked'
* if the the configured {@link #setValue(Object) value} is equal to the bound value.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
*/
public class CheckboxTag extends AbstractHtmlInputElementTag {
private Object value;
/**
* Set the value of the 'value' attribute.
* May be a runtime expression.
*/
public void setValue(Object value) {
Assert.notNull(value, "'value' must not be null");
this.value = value;
}
/**
* Get the value of the 'value' attribute.
* May be a runtime expression.
*/
protected Object getValue() {
return this.value;
}
/**
* Writes the 'input(checkbox)' to the supplied {@link TagWriter},
* marking it as 'checked' if appropriate.
*/
protected int writeTagContent(TagWriter tagWriter) throws JspException {
tagWriter.startTag("input");
writeDefaultAttributes(tagWriter);
tagWriter.writeAttribute("type", "checkbox");
Object boundValue = getBoundValue();
Class valueType = getBindStatus().getValueType();
if (Boolean.class.equals(valueType) || boolean.class.equals(valueType)) {
// the concrete type may not be a Boolean - can be String
if (boundValue instanceof String) {
boundValue = Boolean.valueOf((String) boundValue);
}
Boolean booleanValue = (boundValue != null ? (Boolean) boundValue : Boolean.FALSE);
renderFromBoolean(booleanValue, tagWriter);
}
else {
Object value = getValue();
if (value == null) {
throw new IllegalArgumentException("Attribute 'value' is required when binding to non-boolean values");
}
Object resolvedValue = (value instanceof String ? evaluate("value", (String) value) : value);
if (boundValue != null && boundValue.getClass().isArray()) {
renderFromCollection(resolvedValue, CollectionUtils.arrayToList(boundValue), tagWriter);
}
else if (boundValue instanceof Collection) {
renderFromCollection(resolvedValue, (Collection) boundValue, tagWriter);
}
else {
renderSingleValue(resolvedValue, tagWriter);
}
}
tagWriter.endTag();
if (!isDisabled()) {
// Write out the 'field was present' marker.
tagWriter.startTag("input");
tagWriter.writeAttribute("type", "hidden");
tagWriter.writeAttribute("name", WebDataBinder.DEFAULT_FIELD_MARKER_PREFIX + getName());
tagWriter.writeAttribute("value", "on");
tagWriter.endTag();
}
return EVAL_PAGE;
}
/**
* Render the 'input(checkbox)' with the supplied value, marking the
* 'input' element as 'checked' if the supplied value matches the
* bound value.
*/
private void renderSingleValue(Object resolvedValue, TagWriter tagWriter) throws JspException {
tagWriter.writeAttribute("value", getDisplayString(resolvedValue));
if (SelectedValueComparator.isSelected(getBindStatus(), resolvedValue)) {
tagWriter.writeAttribute("checked", "checked");
}
}
/**
* Render the 'input(checkbox)' with the supplied value, marking
* the 'input' element as 'checked' if the supplied value is
* present in the bound Collection value.
*/
private void renderFromCollection(Object resolvedValue, Collection boundValue, TagWriter tagWriter) throws JspException {
tagWriter.writeAttribute("value", getDisplayString(resolvedValue));
if (SelectedValueComparator.isSelected(getBindStatus(), resolvedValue)) {
tagWriter.writeAttribute("checked", "checked");
}
}
/**
* Render the 'input(checkbox)' with the supplied value, marking
* the 'input' element as 'checked' if the supplied Boolean is
* true.
*/
private void renderFromBoolean(Boolean boundValue, TagWriter tagWriter) throws JspException {
tagWriter.writeAttribute("value", "true");
if (boundValue.booleanValue()) {
tagWriter.writeAttribute("checked", "checked");
}
}
/**
* Return a unique ID for the bound name within the current PageContext.
*/
protected String autogenerateId() throws JspException {
return TagIdGenerator.nextId(getName(), this.pageContext);
}
}