taglibs-rdc/src/main/java/org/apache/taglibs/rdc/dm/DMUtils.java - tomcat-taglibs-rdc - Git at Google

 /*
  * 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.
  */
 package org.apache.taglibs.rdc.dm;

 import java.text.MessageFormat;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.regex.Pattern;
 import java.util.regex.Matcher;
 import javax.servlet.jsp.JspContext;
 import javax.servlet.jsp.el.VariableResolver;
 import org.apache.commons.el.ExpressionEvaluatorImpl;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;

 import org.apache.taglibs.rdc.RDCUtils;
 import org.apache.taglibs.rdc.core.BaseModel;
 import org.apache.taglibs.rdc.core.ComponentModel;
 import org.apache.taglibs.rdc.core.Constants;
 import org.apache.taglibs.rdc.core.GroupModel;
 import org.apache.taglibs.rdc.core.GroupTag;
 /**
  * Utility methods for the dm package
  *
  * @author Rahul Akolkar
  */
 public class DMUtils {

     // ******************
     // PRIVATE CONSTANTS
     // ******************
     private static final String NESTED_DATAMODEL_SEPARATOR = "|";

     private static final String FILLER = ".*";
     private static final String ID_TOK = "\\$((\\w|_|\\" +
         NESTED_DATAMODEL_SEPARATOR + ")+)";
     private static final String START_EXPR = "\\#\\{";
     private static final String FILLER_NO_END_EXPR = "[^\\}]*";

     private static final Pattern PATTERN_ID =
         Pattern.compile(FILLER + ID_TOK + FILLER);
     private static final int ID_GROUP = 1;
     private static final Pattern PATTERN_OPEN_EXPR =
         Pattern.compile(FILLER + START_EXPR + FILLER_NO_END_EXPR);

     // Error messages (to be i18n'zed)
     private static final String ERR_NO_SUCH_MODEL = "No model for " +
         "\"{0}\" found as child of \"{1}\"";
     private static final String ERR_NULL_EXPR = "EL error, \"{0}\"" +
         "; JspContext or expression or return type is null";
     private static final String ERR_BAD_EXPR = "EL error while " +
         "evaluating expression: \"{0}\"";

     // Logging
     private static Log log = LogFactory.getLog(DMUtils.class);

     // ******************
     // PUBLIC METHODS
     // ******************
     /**
      * Return true if the given component or container is done.
      *
      * @param model The {@link BaseModel} to check.
      */
     public static boolean isChildDone(BaseModel model) {
         if (model instanceof GroupModel) {
             GroupModel grpModel = (GroupModel) model;
             if (grpModel.getGroupConfirm() != null) {
                 if (grpModel.getState() == Constants.GRP_STATE_DONE) {
                     return true;
                 }
             } else {
                 if (grpModel.getActiveChildren().size() == 0) {
                     grpModel.setState(Constants.GRP_STATE_DONE);
                     return true;
                 }
             }
             return false;
         } else if (model instanceof ComponentModel &&
                    model.getState() == Constants.FSM_DONE) {
             return true;
         } else if (model instanceof BaseModel &&
                 model.getState() == Constants.FSM_DONE) {
             return true;
         }
         return false;
     }

     // ******************
     // PACKAGE METHODS
     // ******************
     /**
      * Activate child so it takes over the dialog from the next turn
      */
     static int invokeDormantChild(Map children, List activeChildren,
         String id) {
         if (id == null) {
             log.info("Null ID of identified target");
             return Constants.GRP_ALL_CHILDREN_DONE;
         }
         BaseModel model = (BaseModel) children.get(id);
         if (model != null) {
             if (model.getState() == Constants.FSM_DORMANT) {
                 activeChildren.add(id);
                 if (model instanceof BaseModel) {
                     model.setState(Constants.FSM_INPUT);
                 } else if (model instanceof GroupModel) {
                     model.setState(Constants.GRP_STATE_RUNNING);
                 } else if (model instanceof ComponentModel) {
                     model.setState(Constants.FSM_INPUT);
                 }
             }
             return Constants.GRP_SOME_CHILD_RUNNING;
         } else {
             log.info("ID \"" + id + "\" of target in group dialog " +
                 "configuration is invalid");
             return Constants.GRP_ALL_CHILDREN_DONE;
         }
     }

     /**
      * Two pass evaluation:
      * 1) Substitute value-of RDCs
      * 2) Evaluate using the EL evaluator
      *
      * @param String to be evaluated
      */
     static Object proprietaryEval(GroupTag groupTag, GroupModel groupModel,
         String expr, Class retClass, LinkedHashMap lruCache,
         List tempVars) {

         Matcher matcher = PATTERN_ID.matcher(expr);
         while (matcher.matches()) {
             String matched = matcher.group(ID_GROUP);
             int start = expr.lastIndexOf(matched) - 1; // -1 for $
             int end = start + 1 + matched.length();
             String startStr = "", endStr = "";
             if (start > 0) {
                 startStr = expr.substring(0, start);
             }
             if (end < expr.length()) {
                 endStr = expr.substring(end);
             }
             Object[] exprData = null;
             Object rdcValue = null;
             String pageVar = null;
             if (lruCache != null && lruCache.containsKey(matched)) {
                 exprData = (Object[])lruCache.get(matched);
                 rdcValue = exprData[0];
                 pageVar = (String)exprData[1];
             }
             if (exprData == null) {
                 rdcValue = valueOfIDExpr(groupModel, matched);
                 pageVar = RDCUtils.getNextRDCVarName();
                 tempVars.add(pageVar);
                 addToCache(lruCache, matched, rdcValue, pageVar);
             }
             groupTag.getJspContext().setAttribute(pageVar, rdcValue);
             expr = wrapAsNeeded(startStr, pageVar, endStr);
             matcher = PATTERN_ID.matcher(expr);
         }
         return valueOfELExpr(groupTag.getJspContext(), expr, retClass);
     }


     // ******************
     // PRIVATE METHODS
     // ******************
     /**
      * LRU Cache implementation using LinkedHashMap
      *
      */
     private static void addToCache(LinkedHashMap cache,
         String key, Object value, String var) {

         final int MAX_CACHE_SIZE = 50;
         if (cache.size() == MAX_CACHE_SIZE) {
             cache.remove(cache.keySet().iterator().next());
         }
         cache.put(key, new Object[] { value, var });
     }

     /**
      * Make sure the temporary page context variable gets evaluated in an
      * EL expression
      *
      */
     private static String wrapAsNeeded(String startStr, String pageVar,
         String endStr) {
         Matcher openExpr = PATTERN_OPEN_EXPR.matcher(startStr);
         if (openExpr.matches()) {
             return startStr + pageVar + endStr;
         }
         return startStr + "#{" + pageVar + "}" + endStr;
     }

     /**
      * Obtain the value of the given ID with respect to the given GroupModel.
      *
      * @param GroupModel The group model which holds a child of the given ID
      * @param String The ID whose value is required
      */
     private static Object valueOfIDExpr(GroupModel groupModel, String id) {
         Object value = null;
         BaseModel iteratorModel = groupModel;
         if (id == null) {
             return null;
         }
         StringTokenizer idTokenizer = new StringTokenizer(id,
             NESTED_DATAMODEL_SEPARATOR);
         BaseModel model = null;
         while (idTokenizer.hasMoreTokens()) {
             String idTok = idTokenizer.nextToken();
             if (iteratorModel instanceof GroupModel) {
                 model = (BaseModel) ((GroupModel)iteratorModel).
                     getLocalMap().get(idTok);
             } else if (iteratorModel instanceof ComponentModel) {
                 model = (BaseModel) ((ComponentModel)iteratorModel).
                     getLocalMap().get(idTok);
             }
             if (model == null) {
                 // Invalid child ID specified in XML navigation rules
                 MessageFormat msgFormat = new MessageFormat(ERR_NO_SUCH_MODEL);
                 log.warn(msgFormat.format(new Object[] {idTok,
                     iteratorModel.getId()}));
                 return "$" + id;
             }
             iteratorModel = model;
         }
         value = model.getValue();
         return value;
     }

     /**
      * Obtain the value of the given JSP 2.0 EL expression in the group
      * tag's PageContext.
      *
      * @param JspContext The context in which the expression should be
      *                   evaluated
      * @param String The JSP 2.0  EL expression
      * @param Class retType The expected return type
      */
     private static Object valueOfELExpr(JspContext ctx, String expr_,
         Class retType) {

         if (ctx == null || expr_ == null || retType == null) {
             MessageFormat msgFormat = new MessageFormat(ERR_NULL_EXPR);
             log.warn(msgFormat.format(new Object[] {expr_}));
             return null;
         }
         String expr = expr_.replaceAll("\\#\\{", "\\$\\{");
         Object value = null;
         if (retType == null) {
             retType = java.lang.String.class;
         }
         ExpressionEvaluatorImpl exprEvaluator = new ExpressionEvaluatorImpl();
         VariableResolver varResolver = ctx.getVariableResolver();
         try {
             value = exprEvaluator.evaluate(expr, retType, varResolver, null);
         } catch (javax.servlet.jsp.el.ELException e) {
             MessageFormat msgFormat = new MessageFormat(ERR_BAD_EXPR);
             log.warn(msgFormat.format(new Object[] {e.getMessage()}), e);
             return null;
         } // end of try-catch
         return value;
     }
 }
	/*
	* 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.
	*/
	package org.apache.taglibs.rdc.dm;

	import java.text.MessageFormat;
	import java.util.LinkedHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.StringTokenizer;
	import java.util.regex.Pattern;
	import java.util.regex.Matcher;
	import javax.servlet.jsp.JspContext;
	import javax.servlet.jsp.el.VariableResolver;
	import org.apache.commons.el.ExpressionEvaluatorImpl;
	import org.apache.commons.logging.Log;
	import org.apache.commons.logging.LogFactory;

	import org.apache.taglibs.rdc.RDCUtils;
	import org.apache.taglibs.rdc.core.BaseModel;
	import org.apache.taglibs.rdc.core.ComponentModel;
	import org.apache.taglibs.rdc.core.Constants;
	import org.apache.taglibs.rdc.core.GroupModel;
	import org.apache.taglibs.rdc.core.GroupTag;
	/**
	* Utility methods for the dm package
	*
	* @author Rahul Akolkar
	*/
	public class DMUtils {

	// ******************
	// PRIVATE CONSTANTS
	// ******************
	private static final String NESTED_DATAMODEL_SEPARATOR = "\|";

	private static final String FILLER = ".*";
	private static final String ID_TOK = "\\$((\\w\|_\|\\" +
	NESTED_DATAMODEL_SEPARATOR + ")+)";
	private static final String START_EXPR = "\\#\\{";
	private static final String FILLER_NO_END_EXPR = "[^\\}]*";

	private static final Pattern PATTERN_ID =
	Pattern.compile(FILLER + ID_TOK + FILLER);
	private static final int ID_GROUP = 1;
	private static final Pattern PATTERN_OPEN_EXPR =
	Pattern.compile(FILLER + START_EXPR + FILLER_NO_END_EXPR);

	// Error messages (to be i18n'zed)
	private static final String ERR_NO_SUCH_MODEL = "No model for " +
	"\"{0}\" found as child of \"{1}\"";
	private static final String ERR_NULL_EXPR = "EL error, \"{0}\"" +
	"; JspContext or expression or return type is null";
	private static final String ERR_BAD_EXPR = "EL error while " +
	"evaluating expression: \"{0}\"";

	// Logging
	private static Log log = LogFactory.getLog(DMUtils.class);

	// ******************
	// PUBLIC METHODS
	// ******************
	/**
	* Return true if the given component or container is done.
	*
	* @param model The {@link BaseModel} to check.
	*/
	public static boolean isChildDone(BaseModel model) {
	if (model instanceof GroupModel) {
	GroupModel grpModel = (GroupModel) model;
	if (grpModel.getGroupConfirm() != null) {
	if (grpModel.getState() == Constants.GRP_STATE_DONE) {
	return true;
	}
	} else {
	if (grpModel.getActiveChildren().size() == 0) {
	grpModel.setState(Constants.GRP_STATE_DONE);
	return true;
	}
	}
	return false;
	} else if (model instanceof ComponentModel &&
	model.getState() == Constants.FSM_DONE) {
	return true;
	} else if (model instanceof BaseModel &&
	model.getState() == Constants.FSM_DONE) {
	return true;
	}
	return false;
	}

	// ******************
	// PACKAGE METHODS
	// ******************
	/**
	* Activate child so it takes over the dialog from the next turn
	*/
	static int invokeDormantChild(Map children, List activeChildren,
	String id) {
	if (id == null) {
	log.info("Null ID of identified target");
	return Constants.GRP_ALL_CHILDREN_DONE;
	}
	BaseModel model = (BaseModel) children.get(id);
	if (model != null) {
	if (model.getState() == Constants.FSM_DORMANT) {
	activeChildren.add(id);
	if (model instanceof BaseModel) {
	model.setState(Constants.FSM_INPUT);
	} else if (model instanceof GroupModel) {
	model.setState(Constants.GRP_STATE_RUNNING);
	} else if (model instanceof ComponentModel) {
	model.setState(Constants.FSM_INPUT);
	}
	}
	return Constants.GRP_SOME_CHILD_RUNNING;
	} else {
	log.info("ID \"" + id + "\" of target in group dialog " +
	"configuration is invalid");
	return Constants.GRP_ALL_CHILDREN_DONE;
	}
	}

	/**
	* Two pass evaluation:
	* 1) Substitute value-of RDCs
	* 2) Evaluate using the EL evaluator
	*
	* @param String to be evaluated
	*/
	static Object proprietaryEval(GroupTag groupTag, GroupModel groupModel,
	String expr, Class retClass, LinkedHashMap lruCache,
	List tempVars) {

	Matcher matcher = PATTERN_ID.matcher(expr);
	while (matcher.matches()) {
	String matched = matcher.group(ID_GROUP);
	int start = expr.lastIndexOf(matched) - 1; // -1 for $
	int end = start + 1 + matched.length();
	String startStr = "", endStr = "";
	if (start > 0) {
	startStr = expr.substring(0, start);
	}
	if (end < expr.length()) {
	endStr = expr.substring(end);
	}
	Object[] exprData = null;
	Object rdcValue = null;
	String pageVar = null;
	if (lruCache != null && lruCache.containsKey(matched)) {
	exprData = (Object[])lruCache.get(matched);
	rdcValue = exprData[0];
	pageVar = (String)exprData[1];
	}
	if (exprData == null) {
	rdcValue = valueOfIDExpr(groupModel, matched);
	pageVar = RDCUtils.getNextRDCVarName();
	tempVars.add(pageVar);
	addToCache(lruCache, matched, rdcValue, pageVar);
	}
	groupTag.getJspContext().setAttribute(pageVar, rdcValue);
	expr = wrapAsNeeded(startStr, pageVar, endStr);
	matcher = PATTERN_ID.matcher(expr);
	}
	return valueOfELExpr(groupTag.getJspContext(), expr, retClass);
	}


	// ******************
	// PRIVATE METHODS
	// ******************
	/**
	* LRU Cache implementation using LinkedHashMap
	*
	*/
	private static void addToCache(LinkedHashMap cache,
	String key, Object value, String var) {

	final int MAX_CACHE_SIZE = 50;
	if (cache.size() == MAX_CACHE_SIZE) {
	cache.remove(cache.keySet().iterator().next());
	}
	cache.put(key, new Object[] { value, var });
	}

	/**
	* Make sure the temporary page context variable gets evaluated in an
	* EL expression
	*
	*/
	private static String wrapAsNeeded(String startStr, String pageVar,
	String endStr) {
	Matcher openExpr = PATTERN_OPEN_EXPR.matcher(startStr);
	if (openExpr.matches()) {
	return startStr + pageVar + endStr;
	}
	return startStr + "#{" + pageVar + "}" + endStr;
	}

	/**
	* Obtain the value of the given ID with respect to the given GroupModel.
	*
	* @param GroupModel The group model which holds a child of the given ID
	* @param String The ID whose value is required
	*/
	private static Object valueOfIDExpr(GroupModel groupModel, String id) {
	Object value = null;
	BaseModel iteratorModel = groupModel;
	if (id == null) {
	return null;
	}
	StringTokenizer idTokenizer = new StringTokenizer(id,
	NESTED_DATAMODEL_SEPARATOR);
	BaseModel model = null;
	while (idTokenizer.hasMoreTokens()) {
	String idTok = idTokenizer.nextToken();
	if (iteratorModel instanceof GroupModel) {
	model = (BaseModel) ((GroupModel)iteratorModel).
	getLocalMap().get(idTok);
	} else if (iteratorModel instanceof ComponentModel) {
	model = (BaseModel) ((ComponentModel)iteratorModel).
	getLocalMap().get(idTok);
	}
	if (model == null) {
	// Invalid child ID specified in XML navigation rules
	MessageFormat msgFormat = new MessageFormat(ERR_NO_SUCH_MODEL);
	log.warn(msgFormat.format(new Object[] {idTok,
	iteratorModel.getId()}));
	return "$" + id;
	}
	iteratorModel = model;
	}
	value = model.getValue();
	return value;
	}

	/**
	* Obtain the value of the given JSP 2.0 EL expression in the group
	* tag's PageContext.
	*
	* @param JspContext The context in which the expression should be
	* evaluated
	* @param String The JSP 2.0 EL expression
	* @param Class retType The expected return type
	*/
	private static Object valueOfELExpr(JspContext ctx, String expr_,
	Class retType) {

	if (ctx == null \|\| expr_ == null \|\| retType == null) {
	MessageFormat msgFormat = new MessageFormat(ERR_NULL_EXPR);
	log.warn(msgFormat.format(new Object[] {expr_}));
	return null;
	}
	String expr = expr_.replaceAll("\\#\\{", "\\$\\{");
	Object value = null;
	if (retType == null) {
	retType = java.lang.String.class;
	}
	ExpressionEvaluatorImpl exprEvaluator = new ExpressionEvaluatorImpl();
	VariableResolver varResolver = ctx.getVariableResolver();
	try {
	value = exprEvaluator.evaluate(expr, retType, varResolver, null);
	} catch (javax.servlet.jsp.el.ELException e) {
	MessageFormat msgFormat = new MessageFormat(ERR_BAD_EXPR);
	log.warn(msgFormat.format(new Object[] {e.getMessage()}), e);
	return null;
	} // end of try-catch
	return value;
	}
	}