/*
* Copyright 2002-2006 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.util;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.Tag;
import org.springframework.util.Assert;
/**
* Utility class for tag library related code, exposing functionality
* such as translating {@link String Strings} to web scopes.
*
* <p>
* <ul>
* <li><code>page</code> will be transformed to
* {@link javax.servlet.jsp.PageContext#PAGE_SCOPE PageContext.PAGE_SCOPE}
* <li><code>request</code> will be transformed to
* {@link javax.servlet.jsp.PageContext#REQUEST_SCOPE PageContext.REQUEST_SCOPE}
* <li><code>session</code> will be transformed to
* {@link javax.servlet.jsp.PageContext#SESSION_SCOPE PageContext.SESSION_SCOPE}
* <li><code>application</code> will be transformed to
* {@link javax.servlet.jsp.PageContext#APPLICATION_SCOPE PageContext.APPLICATION_SCOPE}
* </ul>
*
* @author Alef Arendsen
* @author Rob Harrop
* @author Juergen Hoeller
* @author Rick Evans
*/
public abstract class TagUtils {
/** Constant identifying the page scope */
public static final String SCOPE_PAGE = "page";
/** Constant identifying the request scope */
public static final String SCOPE_REQUEST = "request";
/** Constant identifying the session scope */
public static final String SCOPE_SESSION = "session";
/** Constant identifying the application scope */
public static final String SCOPE_APPLICATION = "application";
/**
* Determines the scope for a given input <code>String</code>.
* <p>If the <code>String</code> does not match 'request', 'session',
* 'page' or 'application', the method will return {@link PageContext#PAGE_SCOPE}.
* @param scope the <code>String</code> to inspect
* @return the scope found, or {@link PageContext#PAGE_SCOPE} if no scope matched
* @throws IllegalArgumentException if the supplied <code>scope</code> is <code>null</code>
*/
public static int getScope(String scope) {
Assert.notNull(scope, "Scope to search for cannot be null");
if (scope.equals(SCOPE_REQUEST)) {
return PageContext.REQUEST_SCOPE;
}
else if (scope.equals(SCOPE_SESSION)) {
return PageContext.SESSION_SCOPE;
}
else if (scope.equals(SCOPE_APPLICATION)) {
return PageContext.APPLICATION_SCOPE;
}
else {
return PageContext.PAGE_SCOPE;
}
}
/**
* Determine whether the supplied {@link Tag} has any ancestor tag
* of the supplied type.
* @param tag the tag whose ancestors are to be checked
* @param ancestorTagClass the ancestor {@link Class} being searched for
* @return <code>true</code> if the supplied {@link Tag} has any ancestor tag
* of the supplied type
* @throws IllegalArgumentException if either of the supplied arguments is <code>null</code>;
* or if the supplied <code>ancestorTagClass</code> is not type-assignable to
* the {@link Tag} class
*/
public static boolean hasAncestorOfType(Tag tag, Class ancestorTagClass) {
Assert.notNull(tag, "Tag cannot be null");
Assert.notNull(ancestorTagClass, "Ancestor tag class cannot be null");
if (!Tag.class.isAssignableFrom(ancestorTagClass)) {
throw new IllegalArgumentException(
"Class '" + ancestorTagClass.getName() + "' is not a valid Tag type");
}
Tag ancestor = tag.getParent();
while (ancestor != null) {
if (ancestorTagClass.isAssignableFrom(ancestor.getClass())) {
return true;
}
ancestor = ancestor.getParent();
}
return false;
}
/**
* Determine whether the supplied {@link Tag} has any ancestor tag
* of the supplied type, throwing an {@link IllegalStateException}
* if not.
* @param tag the tag whose ancestors are to be checked
* @param ancestorTagClass the ancestor {@link Class} being searched for
* @param tagName the name of the <code>tag</code>; for example '<code>option</code>'
* @param ancestorTagName the name of the ancestor <code>tag</code>; for example '<code>select</code>'
* @throws IllegalStateException if the supplied <code>tag</code> does not
* have a tag of the supplied <code>parentTagClass</code> as an ancestor
* @throws IllegalArgumentException if any of the supplied arguments is <code>null</code>,
* or in the case of the {@link String}-typed arguments, is composed wholly
* of whitespace; or if the supplied <code>ancestorTagClass</code> is not
* type-assignable to the {@link Tag} class
* @see #hasAncestorOfType(javax.servlet.jsp.tagext.Tag, Class)
*/
public static void assertHasAncestorOfType(Tag tag, Class ancestorTagClass, String tagName, String ancestorTagName) {
Assert.hasText(tagName, "'tagName' must not be empty");
Assert.hasText(ancestorTagName, "'ancestorTagName' must not be empty");
if (!TagUtils.hasAncestorOfType(tag, ancestorTagClass)) {
throw new IllegalStateException("The '" + tagName + "' tag can only be used inside a valid '" + ancestorTagName + "' tag.");
}
}
}
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