nbubna 2003/03/10 13:37:41
Added: src/java/org/apache/velocity/tools/generic RenderTool.java
src/java/org/apache/velocity/tools/view/tools
ViewRenderTool.java
Log:
Initial revision
Revision Changes Path
1.1
jakarta-velocity-tools/src/java/org/apache/velocity/tools/generic/RenderTool.java
Index: RenderTool.java
===================================================================
/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 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", "Velocity", 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 [EMAIL PROTECTED]
*
* 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
* 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.
* ====================================================================
*
* 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/>.
*/
package org.apache.velocity.tools.generic;
import java.io.StringWriter;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.context.Context;
/**
* This tool expose static methods to evaluate the given
* strings as VTL (Velocity Template Language)
* using the given context.<br>
*
* <pre>
* Example of eval():
* Input
* -----
* #set( $list = [1,2,3] )
* #set( $object = '$list' )
* #set( $method = 'size()' )
* $render.eval($ctx, "${object}.$method")
*
* Output
* ------
* 3
*
* Example of recurse():
* Input
* -----
* #macro( say_hi )hello world!#end
* #set( $foo = '#say_hi()' )
* #set( $bar = '$foo' )
* $render.recurse($ctx, $bar)
*
* Output
* ------
* hello world!
*
* </pre>
*
* <p>Ok, so these examples are really lame. But, it seems like
* someone out there is always asking how to do stuff like this
* and we always tell them to write a tool. Now we can just tell
* them to use this tool.</p>
*
* <p>This tool is safe (and optimized) for use in the application
* scope of a servlet environment.</p>
*
* @author <a href="mailto:[EMAIL PROTECTED]">Nathan Bubna</a>
* @version $Revision: 1.1 $ $Date: 2003/03/10 21:37:41 $
*/
public class RenderTool
{
/**
* Constructs a new instance
*/
public RenderTool()
{}
private static final String LOG_TAG = "RenderTool.eval()";
/**
* <p>Evaluates a String containing VTL using the current context,
* and returns the result as a String. If this fails, then
* <code>null</code> will be returned. This evaluation is not
* recursive.</p>
*
* @param ctx the current Context
* @param vtl the code to be evaluated
* @return the evaluated code as a String
*/
public static String eval(Context ctx, String vtl) throws Exception
{
StringWriter sw = new StringWriter();
boolean success = Velocity.evaluate(ctx, sw, LOG_TAG, vtl);
if (success)
{
return sw.toString();
}
/* or would it be preferable to return the original? */
return null;
}
/**
* <p>Recursively evaluates a String containing VTL using the
* current context, and returns the result as a String. It
* will continue to re-evaluate the output of the last
* evaluation until an evaluation returns the same code
* that was fed into it.</p>
*
* FIXME? add a parse-depth to prevent infinite recursion?
*
* @param ctx the current Context
* @param vtl the code to be evaluated
* @return the evaluated code as a String
*/
public static String recurse(Context ctx, String vtl) throws Exception
{
String result = eval(ctx, vtl);
if (result.equals(vtl))
{
return result;
}
else
{
return recurse(ctx, result);
}
}
}
1.1
jakarta-velocity-tools/src/java/org/apache/velocity/tools/view/tools/ViewRenderTool.java
Index: ViewRenderTool.java
===================================================================
/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 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", "Velocity", 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 [EMAIL PROTECTED]
*
* 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
* 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.
* ====================================================================
*
* 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/>.
*/
package org.apache.velocity.tools.view.tools;
import java.io.StringWriter;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.generic.RenderTool;
import org.apache.velocity.tools.view.tools.ViewTool;
/**
* This tool expose methods to evaluate the given
* strings as VTL (Velocity Template Language)
* and automatically using the current context.<br>
*
* <pre>
* Example of eval():
* Input
* -----
* #set( $list = [1,2,3] )
* #set( $object = '$list' )
* #set( $method = 'size()' )
* $render.eval("${object}.$method")
*
* Output
* ------
* 3
*
* Example of recurse():
* Input
* -----
* #macro( say_hi )hello world!#end
* #set( $foo = '#say_hi()' )
* #set( $bar = '$foo' )
* $render.recurse('$bar')
*
* Output
* ------
* hello world!
*
* </pre>
*
* <p>Ok, so these examples are really lame. But, it seems like
* someone out there is always asking how to do stuff like this
* and we always tell them to write a tool. Now we can just tell
* them to use this tool.</p>
*
* <p>This tool is NOT meant to be used in either application or
* session scopes of a servlet environment.</p>
*
* @author <a href="mailto:[EMAIL PROTECTED]">Nathan Bubna</a>
* @version $Revision: 1.1 $ $Date: 2003/03/10 21:37:41 $
*/
public class ViewRenderTool extends RenderTool implements ViewTool
{
private Context context;
/**
* Constructs a new instance
*/
public ViewRenderTool()
{}
/**
* Initializes this instance.
*
* @param obj the current Context
*/
public void init(Object obj)
{
context = (Context)obj;
}
/**
* <p>Evaluates a String containing VTL using the current context,
* and returns the result as a String. If this fails, then
* <code>null</code> will be returned. This evaluation is not
* recursive.</p>
*
* @param vtl the code to be evaluated
* @return the evaluated code as a String
*/
public String eval(String vtl) throws Exception
{
return eval(context, vtl);
}
/**
* <p>Recursively evaluates a String containing VTL using the
* current context, and returns the result as a String. It
* will continue to re-evaluate the output of the last
* evaluation until an evaluation returns the same code
* that was fed into it.</p>
*
* FIXME? add a parse-depth to prevent infinite recursion?
*
* @param vtl the code to be evaluated
* @return the evaluated code as a String
*/
public String recurse(String vtl) throws Exception
{
return recurse(context, vtl);
}
}
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