nbubna 2004/05/03 20:32:22
Added: src/java/org/apache/velocity/tools/generic Alternator.java
AlternatorTool.java
Log:
initial revision of convenient 'alternator' support
Revision Changes Path
1.1
jakarta-velocity-tools/src/java/org/apache/velocity/tools/generic/Alternator.java
Index: Alternator.java
===================================================================
/*
* Copyright 2004 The Apache Software Foundation.
*
* 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.apache.velocity.tools.generic;
import java.util.List;
/**
* Utility class for easily alternating over values in a list.
*
* <p><b>Example Use:</b>
* <pre>
* java...
* List myColors = new ArrayList();
* myColors.add("red");
* myColors.add("blue");
* context.put("color", new Alternator(myColors));
* List myStyles = new ArrayList();
* myColors.add("hip");
* myColors.add("fly");
* myColors.add("groovy");
* // use auto alternation
* context.put("style", new Alternator(true, myStyles));
*
* template...
* #foreach( $foo in [1..5] )
* $foo is $color.next and $style
* #end
*
* output...
* 1 is red and hip
* 2 is blue and fly
* 3 is red and groovy
* 4 is blue and hip
* 5 is red and fly
* </pre></p>
*
* @version $Revision: 1.1 $ $Date: 2004/05/04 03:32:22 $
*/
public class Alternator
{
private List list;
private int index = 0;
private boolean auto = false;
/**
* Creates a new Alternator for the specified list.
*/
public Alternator(List list)
{
this.list = list;
}
/**
* Creates a new Alternator for the specified list with the specified
* automatic shifting preference. See [EMAIL PROTECTED] #setAuto(boolean auto)}.
*/
public Alternator(boolean auto, List list)
{
this.auto = auto;
this.list = list;
}
/**
* Returns true if this Alternator shifts the list index automatically
* after a call to toString().
*/
public boolean isAuto()
{
return auto;
}
/**
* If set to true, the list index will shift automatically after a
* call to toString().
*/
public void setAuto(boolean auto)
{
this.auto = auto;
}
/**
* Manually shifts the list index. If it reaches the end of the list,
* it will start over again at zero.
*/
public void shift()
{
index = (index + 1) % list.size();
}
/**
* Returns the current item without shifting the list index.
*/
public Object getCurrent()
{
return list.get(index);
}
/**
* Returns the current item before shifting the list index.
*/
public Object getNext()
{
Object o = getCurrent();
shift();
return o;
}
/**
* Returns a string representation of the current item or
* <code>null</code> if the current item is null. Also,
* if <i>auto</i> is true, this will shift after returning
* the current item.
*/
public String toString()
{
Object o = list.get(index);
if (auto)
{
shift();
}
if (o == null)
{
return null;
}
return o.toString();
}
}
1.1
jakarta-velocity-tools/src/java/org/apache/velocity/tools/generic/AlternatorTool.java
Index: AlternatorTool.java
===================================================================
/*
* Copyright 2004 The Apache Software Foundation.
*
* 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.apache.velocity.tools.generic;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
/**
* Simple tool to provide easy in-template instantiation of
* [EMAIL PROTECTED] Alternator}s from varying "list" types.
*
* <p><b>Example Use:</b>
* <pre>
* toolbox.xml...
* <tool>
* <key>alternator</key>
* <scope>application</scope>
* <class>org.apache.velocity.tools.generic.AlternatorTool</class>
* </tool>
*
* template...
* #set( $color = $alternator.make('red', 'blue') )
* #set( $style = $alternator.make(true, ['hip','fly','groovy']) )
* #foreach( $i in [1..5] )
* $i is $color.next and $style
* #end
*
* output...
* 1 is red and hip
* 2 is blue and fly
* 3 is red and groovy
* 4 is blue and hip
* 5 is red and fly
* </pre></p>
*
* @version $Revision: 1.1 $ $Date: 2004/05/04 03:32:22 $
*/
public class AlternatorTool
{
public AlternatorTool() {}
/**
* Make a non-automatic [EMAIL PROTECTED] Alternator} from a List.
*/
public Alternator make(List list)
{
return make(false, list);
}
/**
* Make an [EMAIL PROTECTED] Alternator} from a List.
*/
public Alternator make(boolean auto, List list)
{
if (list == null)
{
return null;
}
return new Alternator(auto, list);
}
/**
* Make a non-automatic [EMAIL PROTECTED] Alternator} from the values
* in the specified collection.
*/
public Alternator make(Collection collection)
{
return make(false, collection);
}
/**
* Make an [EMAIL PROTECTED] Alternator} from the values
* in the specified collection.
*/
public Alternator make(boolean auto, Collection collection)
{
if (collection == null)
{
return null;
}
return make(auto, new ArrayList(collection));
}
/**
* Make a non-automatic [EMAIL PROTECTED] Alternator} from an object array.
*/
public Alternator make(Object[] array)
{
return make(false, array);
}
/**
* Make an [EMAIL PROTECTED] Alternator} from an object array.
*/
public Alternator make(boolean auto, Object[] array)
{
if (array == null)
{
return null;
}
return make(auto, Arrays.asList(array));
}
/**
* Make a non-automatic [EMAIL PROTECTED] Alternator} from a list containing the
two
* specified objects.
*/
public Alternator make(Object o1, Object o2)
{
return make(false, o1, o2);
}
/**
* Make an [EMAIL PROTECTED] Alternator} from a list containing the two
* specified objects.
*/
public Alternator make(boolean auto, Object o1, Object o2)
{
List list = new ArrayList();
list.add(o1);
list.add(o2);
return make(auto, list);
}
}
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