/*
* 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 java.beans.PropertyEditor;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import org.springframework.beans.PropertyAccessor;
import org.springframework.core.Conventions;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.support.BindStatus;
import org.springframework.web.servlet.tags.EditorAwareTag;
import org.springframework.web.servlet.tags.NestedPathTag;
/**
* Base tag for all data-binding aware JSP form tags.
*
* <p>Provides the common {@link #setPath path} and {@link #setId id} properties.
* Provides sub-classes with utility methods for accessing the {@link BindStatus}
* of their bound value and also for {@link #writeOptionalAttribute interacting}
* with the {@link TagWriter}.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
*/
public abstract class AbstractDataBoundFormElementTag extends AbstractFormTag implements EditorAwareTag {
/**
* Name of the exposed path variable within the scope of this tag: "nestedPath".
* Same value as {@link org.springframework.web.servlet.tags.NestedPathTag#NESTED_PATH_VARIABLE_NAME}.
*/
protected static final String NESTED_PATH_VARIABLE_NAME = NestedPathTag.NESTED_PATH_VARIABLE_NAME;
/**
* The name of the {@link javax.servlet.jsp.PageContext} attribute under which the
* command object name is exposed.
* @deprecated as of Spring 2.5, in favor of {@link FormTag#MODEL_ATTRIBUTE_VARIABLE_NAME}
*/
public static final String COMMAND_NAME_VARIABLE_NAME =
Conventions.getQualifiedAttributeName(AbstractFormTag.class, "commandName");
/**
* The property path from the {@link FormTag#setModelAttribute form object}.
*/
private String path;
/**
* The value of the '<code>id</code>' attribute.
*/
private String id;
/**
* The {@link BindStatus} of this tag.
*/
private BindStatus bindStatus;
/**
* Set the property path from the {@link FormTag#setModelAttribute form object}.
* May be a runtime expression.
*/
public void setPath(String path) {
this.path = path;
}
/**
* Get the {@link #evaluate resolved} property path for the
* {@link FormTag#setModelAttribute form object}.
*/
protected final String getPath() throws JspException {
String resolvedPath = (String) evaluate("path", this.path);
return (resolvedPath != null ? resolvedPath : "");
}
/**
* Set the value of the '<code>id</code>' attribute.
* <p>May be a runtime expression; defaults to the value of {@link #getName()}.
* Note that the default value may not be valid for certain tags.
*/
public void setId(String id) {
this.id = id;
}
/**
* Get the value of the '<code>id</code>' attribute.
*/
public String getId() {
return this.id;
}
/**
* Writes the default set of attributes to the supplied {@link TagWriter}.
* Further abstract sub-classes should override this method to add in
* any additional default attributes but <strong>must</strong> remember
* to call the <code>super</code> method.
* <p>Concrete sub-classes should call this method when/if they want
* to render default attributes.
* @param tagWriter the {@link TagWriter} to which any attributes are to be written
*/
protected void writeDefaultAttributes(TagWriter tagWriter) throws JspException {
writeOptionalAttribute(tagWriter, "id", resolveId());
writeOptionalAttribute(tagWriter, "name", getName());
}
/**
* Determine the '<code>id</code>' attribute value for this tag,
* autogenerating one if none specified.
* @see #getId()
* @see #autogenerateId()
*/
protected String resolveId() throws JspException {
Object id = evaluate("id", getId());
if (id != null) {
String idString = id.toString();
return (StringUtils.hasText(idString) ? idString : null);
}
return autogenerateId();
}
/**
* Autogenerate the '<code>id</code>' attribute value for this tag.
* <p>The default implementation simply delegates to {@link #getName()},
* deleting invalid characters (such as "[" or "]").
*/
protected String autogenerateId() throws JspException {
return getName();
}
/**
* Get the value for the HTML '<code>name</code>' attribute.
* <p>The default implementation simply delegates to
* {@link #getPropertyPath()} to use the property path as the name.
* For the most part this is desirable as it links with the server-side
* expectation for databinding. However, some subclasses may wish to change
* the value of the '<code>name</code>' attribute without changing the bind path.
* @return the value for the HTML '<code>name</code>' attribute
*/
protected String getName() throws JspException {
return StringUtils.deleteAny(getPropertyPath(), "[]");
}
/**
* Get the {@link BindStatus} for this tag.
*/
protected BindStatus getBindStatus() throws JspException {
if (this.bindStatus == null) {
// HTML escaping in tags is performed by the ValueFormatter class.
String nestedPath = getNestedPath();
String pathToUse = (nestedPath != null ? nestedPath + getPath() : getPath());
if (pathToUse.endsWith(PropertyAccessor.NESTED_PROPERTY_SEPARATOR)) {
pathToUse = pathToUse.substring(0, pathToUse.length() - 1);
}
this.bindStatus = new BindStatus(getRequestContext(), pathToUse, false);
}
return this.bindStatus;
}
/**
* Get the value of the nested path that may have been exposed by the
* {@link NestedPathTag}.
*/
protected String getNestedPath() {
return (String) this.pageContext.getAttribute(NESTED_PATH_VARIABLE_NAME, PageContext.REQUEST_SCOPE);
}
/**
* Build the property path for this tag, including the nested path
* but <i>not</i> prefixed with the name of the form attribute.
* @see #getNestedPath()
* @see #getPath()
*/
protected String getPropertyPath() throws JspException {
String expression = getBindStatus().getExpression();
return (expression != null ? expression : "");
}
/**
* Get the bound value.
* @see #getBindStatus()
*/
protected final Object getBoundValue() throws JspException {
return getBindStatus().getValue();
}
/**
* Get the {@link PropertyEditor}, if any, in use for value bound to this tag.
*/
protected PropertyEditor getPropertyEditor() throws JspException {
return getBindStatus().getEditor();
}
/**
* Exposes the {@link PropertyEditor} for {@link EditorAwareTag}.
* <p>Use {@link #getPropertyEditor()} for internal rendering purposes.
*/
public final PropertyEditor getEditor() throws JspException {
return getPropertyEditor();
}
/**
* Disposes of the {@link BindStatus} instance.
*/
public void doFinally() {
super.doFinally();
this.bindStatus = null;
}
}