https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * 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 java.beans.PropertyEditor;

import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;

import org.springframework.beans.PropertyAccessor;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.support.BindStatus;
import org.springframework.web.servlet.support.RequestDataValueProcessor;
import org.springframework.web.servlet.tags.EditorAwareTag;
import org.springframework.web.servlet.tags.NestedPathTag;


Base tag for all data-binding aware JSP form tags.

Provides the common path and id properties. Provides sub-classes with utility methods for accessing the BindStatus of their bound value and also for interacting with the TagWriter. 
Author:Rob Harrop, Juergen Hoeller
Since:2.0
/**
 * 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
 */
@SuppressWarnings("serial")
public abstract class AbstractDataBoundFormElementTag extends AbstractFormTag implements EditorAwareTag {

	
Name of the exposed path variable within the scope of this tag: "nestedPath". Same value as NestedPathTag.NESTED_PATH_VARIABLE_NAME. 
/**
	 * 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 property path from the form object. 
/**
	 * The property path from the {@link FormTag#setModelAttribute form object}.
	 */
	@Nullable
	private String path;

	
The value of the 'id' attribute. 
/**
	 * The value of the '{@code id}' attribute.
	 */
	@Nullable
	private String id;

	
The BindStatus of this tag. 
/**
	 * The {@link BindStatus} of this tag.
	 */
	@Nullable
	private BindStatus bindStatus;


	
Set the property path from the form object. May be a runtime expression. 
/**
	 * 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 resolved property path for the form object. 
/**
	 * 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 'id' attribute. 
May be a runtime expression; defaults to the value of getName(). Note that the default value may not be valid for certain tags. 
/**
	 * Set the value of the '{@code id}' 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.
	 */
	@Override
	public void setId(@Nullable String id) {
		this.id = id;
	}

	
Get the value of the 'id' attribute. 
/**
	 * Get the value of the '{@code id}' attribute.
	 */
	@Override
	@Nullable
	public String getId() {
		return this.id;
	}


	
Writes the default set of attributes to the supplied TagWriter. Further abstract sub-classes should override this method to add in any additional default attributes but must remember to call the super method. 
Concrete sub-classes should call this method when/if they want
to render default attributes.

Params:
  • tagWriter – the TagWriter to which any attributes are to be written
/**
	 * 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} 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 'id' attribute value for this tag, autogenerating one if none specified. 
See Also:
/**
	 * Determine the '{@code id}' attribute value for this tag,
	 * autogenerating one if none specified.
	 * @see #getId()
	 * @see #autogenerateId()
	 */
	@Nullable
	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 'id' attribute value for this tag. 
The default implementation simply delegates to getName(), deleting invalid characters (such as "[" or "]"). 
/**
	 * Autogenerate the '{@code id}' attribute value for this tag.
	 * <p>The default implementation simply delegates to {@link #getName()},
	 * deleting invalid characters (such as "[" or "]").
	 */
	@Nullable
	protected String autogenerateId() throws JspException {
		String name = getName();
		return (name != null ? StringUtils.deleteAny(name, "[]") : null);
	}

	
Get the value for the HTML 'name' attribute. 
The default implementation simply delegates to 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 data binding. However, some subclasses may wish to change the value of the 'name' attribute without changing the bind path. 
Returns:the value for the HTML 'name' attribute
/**
	 * Get the value for the HTML '{@code name}' 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 data binding. However, some subclasses may wish to change
	 * the value of the '{@code name}' attribute without changing the bind path.
	 * @return the value for the HTML '{@code name}' attribute
	 */
	@Nullable
	protected String getName() throws JspException {
		return getPropertyPath();
	}

	
Get the BindStatus for this tag. 
/**
	 * 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 NestedPathTag. 
/**
	 * Get the value of the nested path that may have been exposed by the
	 * {@link NestedPathTag}.
	 */
	@Nullable
	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 not prefixed with the name of the form attribute.

See Also:
  • getNestedPath()
  • getPath()
/**
	 * 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 Also:
  • getBindStatus()
/**
	 * Get the bound value.
	 * @see #getBindStatus()
	 */
	@Nullable
	protected final Object getBoundValue() throws JspException {
		return getBindStatus().getValue();
	}

	
Get the PropertyEditor, if any, in use for value bound to this tag. 
/**
	 * Get the {@link PropertyEditor}, if any, in use for value bound to this tag.
	 */
	@Nullable
	protected PropertyEditor getPropertyEditor() throws JspException {
		return getBindStatus().getEditor();
	}

	
Exposes the PropertyEditor for EditorAwareTag. 
Use getPropertyEditor() for internal rendering purposes. 
/**
	 * Exposes the {@link PropertyEditor} for {@link EditorAwareTag}.
	 * <p>Use {@link #getPropertyEditor()} for internal rendering purposes.
	 */
	@Override
	@Nullable
	public final PropertyEditor getEditor() throws JspException {
		return getPropertyEditor();
	}

	
Get a display String for the given value, converted by a PropertyEditor
that the BindStatus may have registered for the value's Class.

/**
	 * Get a display String for the given value, converted by a PropertyEditor
	 * that the BindStatus may have registered for the value's Class.
	 */
	protected String convertToDisplayString(@Nullable Object value) throws JspException {
		PropertyEditor editor = (value != null ? getBindStatus().findEditor(value.getClass()) : null);
		return getDisplayString(value, editor);
	}

	
Process the given form field through a RequestDataValueProcessor instance if one is configured or otherwise returns the same value. 
/**
	 * Process the given form field through a {@link RequestDataValueProcessor}
	 * instance if one is configured or otherwise returns the same value.
	 */
	protected final String processFieldValue(@Nullable String name, String value, String type) {
		RequestDataValueProcessor processor = getRequestContext().getRequestDataValueProcessor();
		ServletRequest request = this.pageContext.getRequest();
		if (processor != null && request instanceof HttpServletRequest) {
			value = processor.processFormFieldValue((HttpServletRequest) request, name, value, type);
		}
		return value;
	}

	
Disposes of the BindStatus instance. 
/**
	 * Disposes of the {@link BindStatus} instance.
	 */
	@Override
	public void doFinally() {
		super.doFinally();
		this.bindStatus = null;
	}

}