/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 javax.servlet.jsp.tagext;
Optional class provided by the tag library author to describe additional
translation-time information not described in the TLD.
The TagExtraInfo class is mentioned in the Tag Library Descriptor file (TLD).
This class can be used:
- to indicate that the tag defines scripting variables
- to perform translation-time validation of the tag attributes.
It is the responsibility of the JSP translator that the initial value
to be returned by calls to getTagInfo() corresponds to a TagInfo
object for the tag being translated. If an explicit call to
setTagInfo() is done, then the object passed will be returned in
subsequent calls to getTagInfo().
The only way to affect the value returned by getTagInfo()
is through a setTagInfo() call, and thus, TagExtraInfo.setTagInfo() is
to be called by the JSP translator, with a TagInfo object that
corresponds to the tag being translated. The call should happen before
any invocation on validate() and before any invocation on
getVariableInfo().
NOTE: It is a (translation time) error for a tag definition
in a TLD with one or more variable subelements to have an associated
TagExtraInfo implementation that returns a VariableInfo array with
one or more elements from a call to getVariableInfo().
/**
* Optional class provided by the tag library author to describe additional
* translation-time information not described in the TLD.
* The TagExtraInfo class is mentioned in the Tag Library Descriptor file (TLD).
*
* <p>
* This class can be used:
* <ul>
* <li> to indicate that the tag defines scripting variables
* <li> to perform translation-time validation of the tag attributes.
* </ul>
*
* <p>
* It is the responsibility of the JSP translator that the initial value
* to be returned by calls to getTagInfo() corresponds to a TagInfo
* object for the tag being translated. If an explicit call to
* setTagInfo() is done, then the object passed will be returned in
* subsequent calls to getTagInfo().
*
* <p>
* The only way to affect the value returned by getTagInfo()
* is through a setTagInfo() call, and thus, TagExtraInfo.setTagInfo() is
* to be called by the JSP translator, with a TagInfo object that
* corresponds to the tag being translated. The call should happen before
* any invocation on validate() and before any invocation on
* getVariableInfo().
*
* <p>
* <b>NOTE:</b> It is a (translation time) error for a tag definition
* in a TLD with one or more variable subelements to have an associated
* TagExtraInfo implementation that returns a VariableInfo array with
* one or more elements from a call to getVariableInfo().
*/
public abstract class TagExtraInfo {
Sole constructor. (For invocation by subclass constructors,
typically implicit.)
/**
* Sole constructor. (For invocation by subclass constructors,
* typically implicit.)
*/
public TagExtraInfo() {
// NOOP by default
}
information on scripting variables defined by the tag associated with
this TagExtraInfo instance.
Request-time attributes are indicated as such in the TagData parameter.
Params: - data – The TagData instance.
Returns: An array of VariableInfo data, or null or a zero length array
if no scripting variables are to be defined.
/**
* information on scripting variables defined by the tag associated with
* this TagExtraInfo instance.
* Request-time attributes are indicated as such in the TagData parameter.
*
* @param data The TagData instance.
* @return An array of VariableInfo data, or null or a zero length array
* if no scripting variables are to be defined.
*/
public VariableInfo[] getVariableInfo(TagData data) {
return ZERO_VARIABLE_INFO;
}
Translation-time validation of the attributes.
Request-time attributes are indicated as such in the TagData parameter.
Note that the preferred way to do validation is with the validate()
method, since it can return more detailed information.
Params: - data – The TagData instance.
See Also: Returns: Whether this tag instance is valid.
/**
* Translation-time validation of the attributes.
* Request-time attributes are indicated as such in the TagData parameter.
* Note that the preferred way to do validation is with the validate()
* method, since it can return more detailed information.
*
* @param data The TagData instance.
* @return Whether this tag instance is valid.
* @see TagExtraInfo#validate
*/
public boolean isValid(TagData data) {
return true;
}
Translation-time validation of the attributes.
Request-time attributes are indicated as such in the TagData parameter.
Because of the higher quality validation messages possible,
this is the preferred way to do validation (although isValid()
still works).
JSP 2.0 and higher containers call validate() instead of isValid().
The default implementation of this method is to call isValid(). If
isValid() returns false, a generic ValidationMessage[] is returned
indicating isValid() returned false.
Params: - data – The TagData instance.
Returns: A null object, or zero length array if no errors, an
array of ValidationMessages otherwise. Since: 2.0
/**
* Translation-time validation of the attributes.
* Request-time attributes are indicated as such in the TagData parameter.
* Because of the higher quality validation messages possible,
* this is the preferred way to do validation (although isValid()
* still works).
*
* <p>JSP 2.0 and higher containers call validate() instead of isValid().
* The default implementation of this method is to call isValid(). If
* isValid() returns false, a generic ValidationMessage[] is returned
* indicating isValid() returned false.</p>
*
* @param data The TagData instance.
* @return A null object, or zero length array if no errors, an
* array of ValidationMessages otherwise.
* @since 2.0
*/
public ValidationMessage[] validate( TagData data ) {
ValidationMessage[] result = null;
if( !isValid( data ) ) {
result = new ValidationMessage[] {
new ValidationMessage( data.getId(), "isValid() == false" ) };
}
return result;
}
Set the TagInfo for this class.
Params: - tagInfo – The TagInfo this instance is extending
/**
* Set the TagInfo for this class.
*
* @param tagInfo The TagInfo this instance is extending
*/
public final void setTagInfo(TagInfo tagInfo) {
this.tagInfo = tagInfo;
}
Get the TagInfo for this class.
Returns: the taginfo instance this instance is extending
/**
* Get the TagInfo for this class.
*
* @return the taginfo instance this instance is extending
*/
public final TagInfo getTagInfo() {
return tagInfo;
}
// private data
private TagInfo tagInfo;
// zero length VariableInfo array
private static final VariableInfo[] ZERO_VARIABLE_INFO = { };
}