/*
* $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/TagSupport.java,v 1.17 2002/08/20 05:02:51 werken Exp $
* $Revision: 1.17 $
* $Date: 2002/08/20 05:02:51 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2002 The Apache Software Foundation. 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 the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* 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 THE APACHE SOFTWARE FOUNDATION OR
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* 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,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* $Id: TagSupport.java,v 1.17 2002/08/20 05:02:51 werken Exp $
*/
package org.apache.commons.jelly;
import org.apache.commons.jelly.impl.CompositeTextScriptBlock;
import org.apache.commons.jelly.impl.ScriptBlock;
import org.apache.commons.jelly.impl.TextScript;
import java.io.StringWriter;
import java.io.Writer;
import java.util.List;
/** <p><code>TagSupport</code> an abstract base class which is useful to
* inherit from if developing your own tag.</p>
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @version $Revision: 1.17 $
*/
public abstract class TagSupport implements Tag {
/** the parent of this tag */
protected Tag parent;
/** the body of the tag */
protected Script body;
/** The current context */
protected Boolean shouldTrim;
protected boolean hasTrimmed;
protected JellyContext context;
/**
* Searches up the parent hierarchy from the given tag
* for a Tag of the given type
*
* @param from the tag to start searching from
* @param tagClass the type of the tag to find
* @return the tag of the given type or null if it could not be found
*/
public static Tag findAncestorWithClass(Tag from, Class tagClass) {
while (from != null) {
if (tagClass.isInstance(from)) {
return from;
}
from = from.getParent();
}
return null;
}
public TagSupport() {
}
public TagSupport(boolean shouldTrim) {
setTrim( shouldTrim );
}
/**
* Sets whether whitespace inside this tag should be trimmed or not.
* Defaults to true so whitespace is trimmed
*/
public void setTrim(boolean shouldTrim) {
if ( shouldTrim ) {
this.shouldTrim = Boolean.TRUE;
}
else {
this.shouldTrim = Boolean.FALSE;
}
}
public boolean isTrim() {
if ( this.shouldTrim == null ) {
Tag parent = getParent();
if ( parent == null ) {
return true;
}
else {
if ( parent instanceof TagSupport ) {
TagSupport parentSupport = (TagSupport) parent;
this.shouldTrim = ( parentSupport.isTrim() ? Boolean.TRUE : Boolean.FALSE );
}
else {
this.shouldTrim = Boolean.TRUE;
}
}
}
return this.shouldTrim.booleanValue();
}
/** @return the parent of this tag */
public Tag getParent() {
return parent;
}
/** Sets the parent of this tag */
public void setParent(Tag parent) {
this.parent = parent;
}
/** @return the body of the tag */
public Script getBody() {
return body;
}
/** Sets the body of the tag */
public void setBody(Script body) {
this.body = body;
this.hasTrimmed = false;
}
/** @return the context in which the tag will be run */
public JellyContext getContext() {
return context;
}
/** Sets the context in which the tag will be run */
public void setContext(JellyContext context) throws Exception {
this.context = context;
}
/**
* Invokes the body of this tag using the given output
*/
public void invokeBody(XMLOutput output) throws Exception {
if ( isTrim() && ! hasTrimmed ) {
trimBody();
}
getBody().run(context, output);
}
// Implementation methods
//-------------------------------------------------------------------------
/**
* Searches up the parent hierarchy for a Tag of the given type
* @return the tag of the given type or null if it could not be found
*/
protected Tag findAncestorWithClass(Class parentClass) {
return findAncestorWithClass(getParent(), parentClass);
}
/**
* Evaluates the given body using a buffer and returns the String
* of the result.
*
* @return the text evaluation of the body
*/
protected String getBodyText() throws Exception {
StringWriter writer = new StringWriter();
invokeBody(XMLOutput.createXMLOutput(writer));
return writer.toString();
}
/**
* Evaluates the given body using a buffer and returns the String
* of the result.
*
* @param shouldEscape Signal if the text should be escaped.
*
* @return the text evaluation of the body
*/
protected String getBodyText(boolean shouldEscape) throws Exception {
StringWriter writer = new StringWriter();
invokeBody(XMLOutput.createXMLOutput(writer,shouldEscape));
return writer.toString();
}
/**
* Find all text nodes inside the top level of this body and
* if they are just whitespace then remove them
*/
protected void trimBody() {
// #### should refactor this code into
// #### trimWhitespace() methods on the Script objects
if ( body instanceof CompositeTextScriptBlock ) {
CompositeTextScriptBlock block = (CompositeTextScriptBlock) body;
List list = block.getScriptList();
int size = list.size();
if ( size > 0 ) {
Script script = (Script) list.get(0);
if ( script instanceof TextScript ) {
TextScript textScript = (TextScript) script;
textScript.trimStartWhitespace();
}
if ( size > 1 ) {
script = (Script) list.get(size - 1);
if ( script instanceof TextScript ) {
TextScript textScript = (TextScript) script;
textScript.trimEndWhitespace();
}
}
}
}
else
if ( body instanceof ScriptBlock ) {
ScriptBlock block = (ScriptBlock) body;
List list = block.getScriptList();
for ( int i = list.size() - 1; i >= 0; i-- ) {
Script script = (Script) list.get(i);
if ( script instanceof TextScript ) {
TextScript textScript = (TextScript) script;
String text = textScript.getText();
text = text.trim();
if ( text.length() == 0 ) {
list.remove(i);
}
else {
textScript.setText(text);
}
}
}
}
else if ( body instanceof TextScript ) {
TextScript textScript = (TextScript) body;
textScript.trimWhitespace();
}
this.hasTrimmed = true;
}
}