/*
* Copyright 2002-2010 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 javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyContent;
import javax.servlet.jsp.tagext.BodyTag;
import org.springframework.util.Assert;
import org.springframework.web.servlet.support.BindStatus;
import org.springframework.web.util.TagUtils;
/**
* JSP tag for rendering an HTML '<code>option</code>' tag.
*
* <p><b>Must be used nested inside a {@link SelectTag}.</b>
*
* <p>Provides full support for databinding by marking an
* '<code>option</code>' as 'selected' if the {@link #setValue value}
* matches the value bound to the out {@link SelectTag}.
*
* <p>The {@link #setValue value} property is required and corresponds to
* the '<code>value</code>' attribute of the rendered '<code>option</code>'.
*
* <p>An optional {@link #setLabel label} property can be specified, the
* value of which corresponds to inner text of the rendered
* '<code>option</code>' tag. If no {@link #setLabel label} is specified
* then the {@link #setValue value} property will be used when rendering
* the inner text.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
*/
public class OptionTag extends AbstractHtmlElementBodyTag implements BodyTag {
/**
* The name of the JSP variable used to expose the value for this tag.
*/
public static final String VALUE_VARIABLE_NAME = "value";
/**
* The name of the JSP variable used to expose the display value for this tag.
*/
public static final String DISPLAY_VALUE_VARIABLE_NAME = "displayValue";
/**
* The name of the '<code>selected</code>' attribute.
*/
private static final String SELECTED_ATTRIBUTE = "selected";
/**
* The name of the '<code>value</code>' attribute.
*/
private static final String VALUE_ATTRIBUTE = VALUE_VARIABLE_NAME;
/**
* The name of the '<code>disabled</code>' attribute.
*/
private static final String DISABLED_ATTRIBUTE = "disabled";
/**
* The 'value' attribute of the rendered HTML <code><option></code> tag.
*/
private Object value;
/**
* The text body of the rendered HTML <code><option></code> tag.
*/
private String label;
private Object oldValue;
private Object oldDisplayValue;
private String disabled;
/**
* Set the 'value' attribute of the rendered HTML <code><option></code> tag.
* <p>May be a runtime expression.
*/
public void setValue(Object value) {
this.value = value;
}
/**
* Get the 'value' attribute of the rendered HTML <code><option></code> tag.
*/
protected Object getValue() {
return this.value;
}
/**
* Set the value of the '<code>disabled</code>' attribute.
* <p>May be a runtime expression.
* @param disabled the value of the '<code>disabled</code>' attribute
*/
public void setDisabled(String disabled) {
this.disabled = disabled;
}
/**
* Get the value of the '<code>disabled</code>' attribute.
*/
protected String getDisabled() {
return this.disabled;
}
/**
* Is the current HTML tag disabled?
* @return <code>true</code> if this tag is disabled
*/
protected boolean isDisabled() throws JspException {
return evaluateBoolean(DISABLED_ATTRIBUTE, getDisabled());
}
/**
* Set the text body of the rendered HTML <code><option></code> tag.
* <p>May be a runtime expression.
*/
public void setLabel(String label) {
Assert.notNull(label, "'label' must not be null");
this.label = label;
}
/**
* Get the text body of the rendered HTML <code><option></code> tag.
*/
protected String getLabel() {
return this.label;
}
@Override
protected void renderDefaultContent(TagWriter tagWriter) throws JspException {
Object value = this.pageContext.getAttribute(VALUE_VARIABLE_NAME);
String label = getLabelValue(value);
renderOption(value, label, tagWriter);
}
@Override
protected void renderFromBodyContent(BodyContent bodyContent, TagWriter tagWriter) throws JspException {
Object value = this.pageContext.getAttribute(VALUE_VARIABLE_NAME);
String label = bodyContent.getString();
renderOption(value, label, tagWriter);
}
/**
* Make sure we are under a '<code>select</code>' tag before proceeding.
*/
@Override
protected void onWriteTagContent() {
assertUnderSelectTag();
}
@Override
protected void exposeAttributes() throws JspException {
Object value = resolveValue();
this.oldValue = this.pageContext.getAttribute(VALUE_VARIABLE_NAME);
this.pageContext.setAttribute(VALUE_VARIABLE_NAME, value);
this.oldDisplayValue = this.pageContext.getAttribute(DISPLAY_VALUE_VARIABLE_NAME);
this.pageContext.setAttribute(DISPLAY_VALUE_VARIABLE_NAME, getDisplayString(value, getBindStatus().getEditor()));
}
@Override
protected BindStatus getBindStatus() {
return (BindStatus) this.pageContext.getAttribute(SelectTag.LIST_VALUE_PAGE_ATTRIBUTE);
}
@Override
protected void removeAttributes() {
if (this.oldValue != null) {
this.pageContext.setAttribute(VALUE_ATTRIBUTE, this.oldValue);
this.oldValue = null;
}
else {
this.pageContext.removeAttribute(VALUE_VARIABLE_NAME);
}
if (this.oldDisplayValue != null) {
this.pageContext.setAttribute(DISPLAY_VALUE_VARIABLE_NAME, this.oldDisplayValue);
this.oldDisplayValue = null;
}
else {
this.pageContext.removeAttribute(DISPLAY_VALUE_VARIABLE_NAME);
}
}
private void renderOption(Object value, String label, TagWriter tagWriter) throws JspException {
tagWriter.startTag("option");
writeOptionalAttribute(tagWriter, "id", resolveId());
writeOptionalAttributes(tagWriter);
String renderedValue = getDisplayString(value, getBindStatus().getEditor());
tagWriter.writeAttribute(VALUE_ATTRIBUTE, renderedValue);
if (isSelected(value)) {
tagWriter.writeAttribute(SELECTED_ATTRIBUTE, SELECTED_ATTRIBUTE);
}
if (isDisabled()) {
tagWriter.writeAttribute(DISABLED_ATTRIBUTE, "disabled");
}
tagWriter.appendValue(label);
tagWriter.endTag();
}
@Override
protected String autogenerateId() throws JspException {
return null;
}
/**
* Returns the value of the label for this '<code>option</code>' element.
* If the {@link #setLabel label} property is set then the resolved value
* of that property is used, otherwise the value of the <code>resolvedValue</code>
* argument is used.
*/
private String getLabelValue(Object resolvedValue) throws JspException {
String label = getLabel();
Object labelObj = (label == null ? resolvedValue : evaluate("label", label));
return getDisplayString(labelObj, getBindStatus().getEditor());
}
private void assertUnderSelectTag() {
TagUtils.assertHasAncestorOfType(this, SelectTag.class, "option", "select");
}
private boolean isSelected(Object resolvedValue) {
return SelectedValueComparator.isSelected(getBindStatus(), resolvedValue);
}
private Object resolveValue() throws JspException {
return evaluate(VALUE_VARIABLE_NAME, getValue());
}
}
|