Show BaseFrame2Tag.java syntax highlighted
/*
* ====================================================================
*
* Frame2 Open Source License
*
* Copyright (c) 2004-2007 Megatome Technologies. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by
* Megatome Technologies."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Frame2 Project", and "Frame2",
* must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact iamthechad@sourceforge.net.
*
* 5. Products derived from this software may not be called "Frame2"
* nor may "Frame2" appear in their names without prior written
* permission of Megatome Technologies.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL MEGATOME TECHNOLOGIES OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*/
package org.megatome.frame2.tagsupport;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.tagext.TryCatchFinally;
import org.megatome.frame2.tagsupport.util.EvalHelper;
/**
* This is the base class used for all tags in the Frame2 framework. It provides
* support for EL attributes, as well as storing tag attributes.
*/
public abstract class BaseFrame2Tag extends BodyTagSupport implements
TryCatchFinally {
/** Attributes of this tag */
protected Map<String, String> attrs = new TreeMap<String, String>();
/** This tag's name */
protected String tagName;
/** Indicate if this tag has a body */
protected boolean tagHasBody;
/**
* Constructor
*/
public BaseFrame2Tag() {
setTagName();
}
/**
* Returns the tagName.
*
* @return String
*/
public String getTagName() {
return this.tagName;
}
/**
* Set the tagName.
*/
protected abstract void setTagName();
/**
* Set an attribute for this tag
*
* @param key
* The key of the attribute
* @param value
* The value of the attribute
*/
protected void setAttr(String key, String value) {
this.attrs.put(key, value);
}
/**
* Remove an attribute from this tag
*
* @param key
* Attribute to remove
*/
protected void removeAttr(String key) {
this.attrs.remove(key);
}
/**
* Get the attribute associated with a key.
*
* @param key
* The key
* @return Attribute value associated with the key, nor null if none found.
*/
protected String getAttr(String key) {
return this.attrs.get(key);
}
/**
* Resets attribute values for tag reuse.
*/
@Override
public void release() {
super.release();
this.attrs.clear();
}
/**
* Release not called until garbage collect.
*
* @see javax.servlet.jsp.tagext.TryCatchFinally#doFinally()
*/
public void doFinally() {
// free resources,
this.attrs.clear();
initializeAttributes();
}
/**
* Override to reset any attributes
*/
protected void initializeAttributes() {
// override to reset any attrs.
}
/**
* Catch any exceptions thrown.
*
* @param t
* The exception to catch
* @see javax.servlet.jsp.tagext.TryCatchFinally#doCatch(Throwable)
*/
public void doCatch(Throwable t) throws Throwable {
throw t;
}
/**
* Clear any resources held by this tag
*/
protected void clear() {
// not implemented
}
/**
* Evaluates and returns a String given the input attribute name and
* attribute value.
*
* @param attrName
* attribute name being evaluated
* @param attrValue
* String value of attribute to be evaluated using EL *
* @exception Exception
* if either the <code>attrValue</code> was null, or the
* resulting evaluated value was null.
* @return Resulting attribute value
*/
protected String evalStringAttr(String attrName, String attrValue)
throws Exception {
return (String) (EvalHelper.eval(getTagName(), attrName, attrValue,
String.class, this, this.pageContext));
}
/**
* Evaluates and returns a HashMap given the input attribute name and
* attribute value.
*
* @param attrName
* Attribute name being evaluated
* @param attrValue
* String value of attribute to be evaluated using EL
* @return Resulting HashMap
* @throws Exception
* If either the <code>attrValue</code> is null, or the
* resulting evaluated value is null.
*/
@SuppressWarnings("unchecked")
protected HashMap<String, Object> evalHashMapAttr(String attrName,
String attrValue) throws Exception {
return (HashMap<String, Object>) (EvalHelper.eval(getTagName(),
attrName, attrValue, HashMap.class, this, this.pageContext));
}
/**
* Evaluates and returns a Collection given the input attribute name and
* attribute value.
*
* @param attrName
* Attribute name being evaluated
* @param attrValue
* String value of attribute to be evaluated using EL
* @return Resulting Collection
* @throws Exception
* If either the <code>attrValue</code> is null, or the
* resulting evaluated value is null.
*/
@SuppressWarnings("unchecked")
protected Collection<Object> evalCollectionAttr(String attrName, String attrValue)
throws Exception {
return (Collection<Object>) (EvalHelper.eval(getTagName(), attrName, attrValue,
Collection.class, this, this.pageContext));
}
/**
* Evaluates and returns an array given the input attribute name and
* attribute value.
*
* @param attrName
* Attribute name being evaluated
* @param attrValue
* String value of attribute to be evaluated using EL
* @return Resulting array
* @throws Exception
* If either the <code>attrValue</code> is null, or the
* resulting evaluated value is null.
*/
protected Object[] evalArrayAttr(String attrName, String attrValue)
throws Exception {
return (Object[]) (EvalHelper.eval(getTagName(), attrName, attrValue,
Object[].class, this, this.pageContext));
}
/**
* Evaluates and returns a String given the input attribute name.
*
* @param attrName
* Attribute name being evaluated
* @return Resulting value
* @throws JspException
* If either the value associated with the <code>attrName</code>
* is null, or the resulting evaluated value is null.
*/
protected String evaluateStringAttribute(String attrName)
throws JspException {
String attrValue = null;
try {
attrValue = evalStringAttr(attrName, getAttr(attrName));
} catch (Exception e) {
throw new JspException(
" Evaluation attribute failed " + e.getMessage(), //$NON-NLS-1$
e);
}
return attrValue;
}
}
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