src/java/org/apache/velocity/runtime/directive/Foreach.java - velocity-engine - Git at Google

 package org.apache.velocity.runtime.directive;

 /*
  * 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.
  */

 import java.io.IOException;
 import java.io.Writer;
 import java.util.Iterator;

 import org.apache.velocity.context.ChainedInternalContextAdapter;
 import org.apache.velocity.context.InternalContextAdapter;
 import org.apache.velocity.exception.MethodInvocationException;
 import org.apache.velocity.exception.ParseErrorException;
 import org.apache.velocity.exception.ResourceNotFoundException;
 import org.apache.velocity.exception.TemplateInitException;
 import org.apache.velocity.exception.VelocityException;
 import org.apache.velocity.runtime.RuntimeConstants;
 import org.apache.velocity.runtime.RuntimeServices;
 import org.apache.velocity.runtime.log.Log;
 import org.apache.velocity.runtime.parser.node.ASTReference;
 import org.apache.velocity.runtime.parser.node.Node;
 import org.apache.velocity.runtime.parser.node.SimpleNode;
 import org.apache.velocity.util.introspection.Info;

 /**
  * Foreach directive used for moving through arrays,
  * or objects that provide an Iterator.
  *
  * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
  * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
  * @author Daniel Rall
  * @version $Id$
  */
 public class Foreach extends Directive
 {
     /**
      * A special context to use when the foreach iterator returns a null.  This
      * is required since the standard context may not support nulls.
      * All puts and gets are passed through, except for the foreach iterator key.
      * @since 1.5
      */
     protected static class NullHolderContext extends ChainedInternalContextAdapter
     {
         private String   loopVariableKey = "";
         private boolean  active = true;

         /**
          * Create the context as a wrapper to be used within the foreach
          * @param key the reference used in the foreach
          * @param context the parent context
          */
         private NullHolderContext( String key, InternalContextAdapter context )
         {
            super(context);
            if( key != null )
                loopVariableKey = key;
         }

         /**
          * Get an object from the context, or null if the key is equal to the loop variable
          * @see org.apache.velocity.context.InternalContextAdapter#get(java.lang.String)
          * @exception MethodInvocationException passes on potential exception from reference method call
          */
         public Object get( String key ) throws MethodInvocationException
         {
             return ( active && loopVariableKey.equals(key) )
                 ? null
                 : super.get(key);
         }

         /**
          * @see org.apache.velocity.context.InternalContextAdapter#put(java.lang.String key, java.lang.Object value)
          */
         public Object put( String key, Object value )
         {
             if( loopVariableKey.equals(key) && (value == null) )
             {
                 active = true;
             }

             return super.put( key, value );
         }

         /**
          * Allows callers to explicitly put objects in the local context.
          * Objects added to the context through this method always end up
          * in the top-level context of possible wrapped contexts.
          *
          * @param key name of item to set.
          * @param value object to set to key.
          * @see org.apache.velocity.context.InternalWrapperContext#localPut(String, Object)
          */
         public Object localPut(final String key, final Object value)
         {
             return put(key, value);
         }

         /**
          * Remove an object from the context
          * @see org.apache.velocity.context.InternalContextAdapter#remove(java.lang.Object key)
          */
         public Object remove(Object key)
         {
            if( loopVariableKey.equals(key) )
            {
              active = false;
            }
            return super.remove(key);
         }
     }

     /**
      * Return name of this directive.
      * @return The name of this directive.
      */
     public String getName()
     {
         return "foreach";
     }

     /**
      * Return type of this directive.
      * @return The type of this directive.
      */
     public int getType()
     {
         return BLOCK;
     }

     /**
      * The name of the variable to use when placing
      * the counter value into the context. Right
      * now the default is $velocityCount.
      */
     private String counterName;

     /**
      * The name of the variable to use when placing
      * iterator hasNext() value into the context.Right
      * now the defailt is $velocityHasNext
      */
     private String hasNextName;

     /**
      * What value to start the loop counter at.
      */
     private int counterInitialValue;

     /**
      * The maximum number of times we're allowed to loop.
      */
     private int maxNbrLoops;

     /**
      * Whether or not to throw an Exception if the iterator is null.
      */
     private boolean skipInvalidIterator;

     /**
      * The reference name used to access each
      * of the elements in the list object. It
      * is the $item in the following:
      *
      * #foreach ($item in $list)
      *
      * This can be used class wide because
      * it is immutable.
      */
     private String elementKey;

     /**
      *  immutable, so create in init
      */
     protected Info uberInfo;

     /**
      *  simple init - init the tree and get the elementKey from
      *  the AST
      * @param rs
      * @param context
      * @param node
      * @throws TemplateInitException
      */
     public void init(RuntimeServices rs, InternalContextAdapter context, Node node)
         throws TemplateInitException
     {
         super.init(rs, context, node);

         counterName = rsvc.getString(RuntimeConstants.COUNTER_NAME);
         hasNextName = rsvc.getString(RuntimeConstants.HAS_NEXT_NAME);
         counterInitialValue = rsvc.getInt(RuntimeConstants.COUNTER_INITIAL_VALUE);
         maxNbrLoops = rsvc.getInt(RuntimeConstants.MAX_NUMBER_LOOPS,
                                   Integer.MAX_VALUE);
         if (maxNbrLoops < 1)
         {
             maxNbrLoops = Integer.MAX_VALUE;
         }
         skipInvalidIterator =
             rsvc.getBoolean(RuntimeConstants.SKIP_INVALID_ITERATOR, true);

         if (rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false))
         {
           // If we are in strict mode then the default for skipInvalidItarator
           // is true.  However, if the property is explicitly set, then honor the setting.
           skipInvalidIterator = rsvc.getBoolean(RuntimeConstants.SKIP_INVALID_ITERATOR, false);
         }

         /*
          *  this is really the only thing we can do here as everything
          *  else is context sensitive
          */
         SimpleNode sn = (SimpleNode) node.jjtGetChild(0);

         if (sn instanceof ASTReference)
         {
             elementKey = ((ASTReference) sn).getRootString();
         }
         else
         {
             /*
              * the default, error-prone way which we'll remove
              *  TODO : remove if all goes well
              */
             elementKey = sn.getFirstToken().image.substring(1);
         }

         /*
          * make an uberinfo - saves new's later on
          */

         uberInfo = new Info(this.getTemplateName(),
                 getLine(),getColumn());
     }

     /**
      * Extension hook to allow subclasses to control whether loop vars
      * are set locally or not. So, those in favor of VELOCITY-285, can
      * make that happen easily by overriding this and having it use
      * context.localPut(k,v). See VELOCITY-630 for more on this.
      */
     protected void put(InternalContextAdapter context, String key, Object value)
     {
         context.put(key, value);
     }

     /**
      *  renders the #foreach() block
      * @param context
      * @param writer
      * @param node
      * @return True if the directive rendered successfully.
      * @throws IOException
      * @throws MethodInvocationException
      * @throws ResourceNotFoundException
      * @throws ParseErrorException
      */
     public boolean render(InternalContextAdapter context,
                            Writer writer, Node node)
         throws IOException,  MethodInvocationException, ResourceNotFoundException,
         	ParseErrorException
     {
         /*
          *  do our introspection to see what our collection is
          */

         Object listObject = node.jjtGetChild(2).value(context);

         if (listObject == null)
              return false;

         Iterator i = null;

         try
         {
             i = rsvc.getUberspect().getIterator(listObject, uberInfo);
         }
         /**
          * pass through application level runtime exceptions
          */
         catch( RuntimeException e )
         {
             throw e;
         }
         catch(Exception ee)
         {
             String msg = "Error getting iterator for #foreach at "+uberInfo;
             rsvc.getLog().error(msg, ee);
             throw new VelocityException(msg, ee);
         }

         if (i == null)
         {
             if (skipInvalidIterator)
             {
                 return false;
             }
             else
             {
                 Node pnode = node.jjtGetChild(2);
                 String msg = "#foreach parameter " + pnode.literal() + " at "
                     + Log.formatFileString(pnode)
                     + " is of type " + listObject.getClass().getName()
                     + " and is either of wrong type or cannot be iterated.";
                 rsvc.getLog().error(msg);
                 throw new VelocityException(msg);
             }
         }

         int counter = counterInitialValue;
         boolean maxNbrLoopsExceeded = false;

         /*
          *  save the element key if there is one, and the loop counter
          */
         Object o = context.get(elementKey);
         Object savedCounter = context.get(counterName);
         Object nextFlag = context.get(hasNextName);

         /*
          * Instantiate the null holder context if a null value
          * is returned by the foreach iterator.  Only one instance is
          * created - it's reused for every null value.
          */
         NullHolderContext nullHolderContext = null;

         while (!maxNbrLoopsExceeded && i.hasNext())
         {
             // TODO: JDK 1.5+ -> Integer.valueOf()
             put(context, counterName , new Integer(counter));
             Object value = i.next();
             put(context, hasNextName, Boolean.valueOf(i.hasNext()));
             put(context, elementKey, value);

             try
             {
                 /*
                  * If the value is null, use the special null holder context
                  */
                 if (value == null)
                 {
                     if (nullHolderContext == null)
                     {
                         // lazy instantiation
                         nullHolderContext = new NullHolderContext(elementKey, context);
                     }
                     node.jjtGetChild(3).render(nullHolderContext, writer);
                 }
                 else
                 {
                     node.jjtGetChild(3).render(context, writer);
                 }
             }
             catch (Break.BreakException ex)
             {
                 // encountered #break directive inside #foreach loop
                 break;
             }

             counter++;

             // Determine whether we're allowed to continue looping.
             // ASSUMPTION: counterInitialValue is not negative!
             maxNbrLoopsExceeded = (counter - counterInitialValue) >= maxNbrLoops;
         }

         /*
          * restores the loop counter (if we were nested)
          * if we have one, else just removes
          */

         if (savedCounter != null)
         {
             context.put(counterName, savedCounter);
         }
         else
         {
             context.remove(counterName);
         }


         /*
          *  restores element key if exists
          *  otherwise just removes
          */

         if (o != null)
         {
             context.put(elementKey, o);
         }
         else
         {
             context.remove(elementKey);
         }

         /*
          * restores the "hasNext" boolean flag if it exists
          */
         if( nextFlag != null )
         {
             context.put(hasNextName, nextFlag);
         }
         else
         {
             context.remove(hasNextName);
         }

         return true;
     }
 }
	package org.apache.velocity.runtime.directive;

	/*
	* 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.
	*/

	import java.io.IOException;
	import java.io.Writer;
	import java.util.Iterator;

	import org.apache.velocity.context.ChainedInternalContextAdapter;
	import org.apache.velocity.context.InternalContextAdapter;
	import org.apache.velocity.exception.MethodInvocationException;
	import org.apache.velocity.exception.ParseErrorException;
	import org.apache.velocity.exception.ResourceNotFoundException;
	import org.apache.velocity.exception.TemplateInitException;
	import org.apache.velocity.exception.VelocityException;
	import org.apache.velocity.runtime.RuntimeConstants;
	import org.apache.velocity.runtime.RuntimeServices;
	import org.apache.velocity.runtime.log.Log;
	import org.apache.velocity.runtime.parser.node.ASTReference;
	import org.apache.velocity.runtime.parser.node.Node;
	import org.apache.velocity.runtime.parser.node.SimpleNode;
	import org.apache.velocity.util.introspection.Info;

	/**
	* Foreach directive used for moving through arrays,
	* or objects that provide an Iterator.
	*
	* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
	* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
	* @author Daniel Rall
	* @version $Id$
	*/
	public class Foreach extends Directive
	{
	/**
	* A special context to use when the foreach iterator returns a null. This
	* is required since the standard context may not support nulls.
	* All puts and gets are passed through, except for the foreach iterator key.
	* @since 1.5
	*/
	protected static class NullHolderContext extends ChainedInternalContextAdapter
	{
	private String loopVariableKey = "";
	private boolean active = true;

	/**
	* Create the context as a wrapper to be used within the foreach
	* @param key the reference used in the foreach
	* @param context the parent context
	*/
	private NullHolderContext( String key, InternalContextAdapter context )
	{
	super(context);
	if( key != null )
	loopVariableKey = key;
	}

	/**
	* Get an object from the context, or null if the key is equal to the loop variable
	* @see org.apache.velocity.context.InternalContextAdapter#get(java.lang.String)
	* @exception MethodInvocationException passes on potential exception from reference method call
	*/
	public Object get( String key ) throws MethodInvocationException
	{
	return ( active && loopVariableKey.equals(key) )
	? null
	: super.get(key);
	}

	/**
	* @see org.apache.velocity.context.InternalContextAdapter#put(java.lang.String key, java.lang.Object value)
	*/
	public Object put( String key, Object value )
	{
	if( loopVariableKey.equals(key) && (value == null) )
	{
	active = true;
	}

	return super.put( key, value );
	}

	/**
	* Allows callers to explicitly put objects in the local context.
	* Objects added to the context through this method always end up
	* in the top-level context of possible wrapped contexts.
	*
	* @param key name of item to set.
	* @param value object to set to key.
	* @see org.apache.velocity.context.InternalWrapperContext#localPut(String, Object)
	*/
	public Object localPut(final String key, final Object value)
	{
	return put(key, value);
	}

	/**
	* Remove an object from the context
	* @see org.apache.velocity.context.InternalContextAdapter#remove(java.lang.Object key)
	*/
	public Object remove(Object key)
	{
	if( loopVariableKey.equals(key) )
	{
	active = false;
	}
	return super.remove(key);
	}
	}

	/**
	* Return name of this directive.
	* @return The name of this directive.
	*/
	public String getName()
	{
	return "foreach";
	}

	/**
	* Return type of this directive.
	* @return The type of this directive.
	*/
	public int getType()
	{
	return BLOCK;
	}

	/**
	* The name of the variable to use when placing
	* the counter value into the context. Right
	* now the default is $velocityCount.
	*/
	private String counterName;

	/**
	* The name of the variable to use when placing
	* iterator hasNext() value into the context.Right
	* now the defailt is $velocityHasNext
	*/
	private String hasNextName;

	/**
	* What value to start the loop counter at.
	*/
	private int counterInitialValue;

	/**
	* The maximum number of times we're allowed to loop.
	*/
	private int maxNbrLoops;

	/**
	* Whether or not to throw an Exception if the iterator is null.
	*/
	private boolean skipInvalidIterator;

	/**
	* The reference name used to access each
	* of the elements in the list object. It
	* is the $item in the following:
	*
	* #foreach ($item in $list)
	*
	* This can be used class wide because
	* it is immutable.
	*/
	private String elementKey;

	/**
	* immutable, so create in init
	*/
	protected Info uberInfo;

	/**
	* simple init - init the tree and get the elementKey from
	* the AST
	* @param rs
	* @param context
	* @param node
	* @throws TemplateInitException
	*/
	public void init(RuntimeServices rs, InternalContextAdapter context, Node node)
	throws TemplateInitException
	{
	super.init(rs, context, node);

	counterName = rsvc.getString(RuntimeConstants.COUNTER_NAME);
	hasNextName = rsvc.getString(RuntimeConstants.HAS_NEXT_NAME);
	counterInitialValue = rsvc.getInt(RuntimeConstants.COUNTER_INITIAL_VALUE);
	maxNbrLoops = rsvc.getInt(RuntimeConstants.MAX_NUMBER_LOOPS,
	Integer.MAX_VALUE);
	if (maxNbrLoops < 1)
	{
	maxNbrLoops = Integer.MAX_VALUE;
	}
	skipInvalidIterator =
	rsvc.getBoolean(RuntimeConstants.SKIP_INVALID_ITERATOR, true);

	if (rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false))
	{
	// If we are in strict mode then the default for skipInvalidItarator
	// is true. However, if the property is explicitly set, then honor the setting.
	skipInvalidIterator = rsvc.getBoolean(RuntimeConstants.SKIP_INVALID_ITERATOR, false);
	}

	/*
	* this is really the only thing we can do here as everything
	* else is context sensitive
	*/
	SimpleNode sn = (SimpleNode) node.jjtGetChild(0);

	if (sn instanceof ASTReference)
	{
	elementKey = ((ASTReference) sn).getRootString();
	}
	else
	{
	/*
	* the default, error-prone way which we'll remove
	* TODO : remove if all goes well
	*/
	elementKey = sn.getFirstToken().image.substring(1);
	}

	/*
	* make an uberinfo - saves new's later on
	*/

	uberInfo = new Info(this.getTemplateName(),
	getLine(),getColumn());
	}

	/**
	* Extension hook to allow subclasses to control whether loop vars
	* are set locally or not. So, those in favor of VELOCITY-285, can
	* make that happen easily by overriding this and having it use
	* context.localPut(k,v). See VELOCITY-630 for more on this.
	*/
	protected void put(InternalContextAdapter context, String key, Object value)
	{
	context.put(key, value);
	}

	/**
	* renders the #foreach() block
	* @param context
	* @param writer
	* @param node
	* @return True if the directive rendered successfully.
	* @throws IOException
	* @throws MethodInvocationException
	* @throws ResourceNotFoundException
	* @throws ParseErrorException
	*/
	public boolean render(InternalContextAdapter context,
	Writer writer, Node node)
	throws IOException, MethodInvocationException, ResourceNotFoundException,
	ParseErrorException
	{
	/*
	* do our introspection to see what our collection is
	*/

	Object listObject = node.jjtGetChild(2).value(context);

	if (listObject == null)
	return false;

	Iterator i = null;

	try
	{
	i = rsvc.getUberspect().getIterator(listObject, uberInfo);
	}
	/**
	* pass through application level runtime exceptions
	*/
	catch( RuntimeException e )
	{
	throw e;
	}
	catch(Exception ee)
	{
	String msg = "Error getting iterator for #foreach at "+uberInfo;
	rsvc.getLog().error(msg, ee);
	throw new VelocityException(msg, ee);
	}

	if (i == null)
	{
	if (skipInvalidIterator)
	{
	return false;
	}
	else
	{
	Node pnode = node.jjtGetChild(2);
	String msg = "#foreach parameter " + pnode.literal() + " at "
	+ Log.formatFileString(pnode)
	+ " is of type " + listObject.getClass().getName()
	+ " and is either of wrong type or cannot be iterated.";
	rsvc.getLog().error(msg);
	throw new VelocityException(msg);
	}
	}

	int counter = counterInitialValue;
	boolean maxNbrLoopsExceeded = false;

	/*
	* save the element key if there is one, and the loop counter
	*/
	Object o = context.get(elementKey);
	Object savedCounter = context.get(counterName);
	Object nextFlag = context.get(hasNextName);

	/*
	* Instantiate the null holder context if a null value
	* is returned by the foreach iterator. Only one instance is
	* created - it's reused for every null value.
	*/
	NullHolderContext nullHolderContext = null;

	while (!maxNbrLoopsExceeded && i.hasNext())
	{
	// TODO: JDK 1.5+ -> Integer.valueOf()
	put(context, counterName , new Integer(counter));
	Object value = i.next();
	put(context, hasNextName, Boolean.valueOf(i.hasNext()));
	put(context, elementKey, value);

	try
	{
	/*
	* If the value is null, use the special null holder context
	*/
	if (value == null)
	{
	if (nullHolderContext == null)
	{
	// lazy instantiation
	nullHolderContext = new NullHolderContext(elementKey, context);
	}
	node.jjtGetChild(3).render(nullHolderContext, writer);
	}
	else
	{
	node.jjtGetChild(3).render(context, writer);
	}
	}
	catch (Break.BreakException ex)
	{
	// encountered #break directive inside #foreach loop
	break;
	}

	counter++;

	// Determine whether we're allowed to continue looping.
	// ASSUMPTION: counterInitialValue is not negative!
	maxNbrLoopsExceeded = (counter - counterInitialValue) >= maxNbrLoops;
	}

	/*
	* restores the loop counter (if we were nested)
	* if we have one, else just removes
	*/

	if (savedCounter != null)
	{
	context.put(counterName, savedCounter);
	}
	else
	{
	context.remove(counterName);
	}


	/*
	* restores element key if exists
	* otherwise just removes
	*/

	if (o != null)
	{
	context.put(elementKey, o);
	}
	else
	{
	context.remove(elementKey);
	}

	/*
	* restores the "hasNext" boolean flag if it exists
	*/
	if( nextFlag != null )
	{
	context.put(hasNextName, nextFlag);
	}
	else
	{
	context.remove(hasNextName);
	}

	return true;
	}
	}