org.kuali.student.common.messagebuilder.impl.AbstractMessageBuilder Maven / Gradle / Ivy
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/**
* Copyright 2010 The Kuali Foundation Licensed under the
* Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.messagebuilder.impl;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.velocity.exception.VelocityException;
import org.kuali.student.common.messagebuilder.MessageTreeBuilder;
import org.kuali.student.common.messagebuilder.booleanmessage.BooleanMessage;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.BinaryMessageTree;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.BooleanFunction;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.BooleanFunctionResult;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.BooleanMessageImpl;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.BooleanNode;
import org.kuali.student.common.messagebuilder.booleanmessage.ast.exceptions.BooleanFunctionException;
import org.kuali.student.common.messagebuilder.impl.exceptions.MessageBuilderException;
import org.kuali.student.common.util.VelocityTemplateEngine;
/**
* This AbstractMessageBuilder class builds a summary message
* from plain strings or Velocity template messages. Summary message is built
* from analysing the outcome of a boolean expression.
* If no language is specified then the default language locale is used.
*/
public abstract class AbstractMessageBuilder {
private final VelocityTemplateEngine templateEngine = new VelocityTemplateEngine();
private String booleanExpression;
private Map messageMap;
private Map messageContextMap;
private String language;
private MessageTreeBuilder treeNodeMessageBuilder;
/**
* Constructor.
*
* @param language Language
* @param treeNodeMessageBuilder AST tree node Message builder
*/
public AbstractMessageBuilder(final String language, final MessageTreeBuilder treeNodeMessageBuilder) {
this.language = language;
this.treeNodeMessageBuilder = treeNodeMessageBuilder;
}
/**
* Builds and evaluates a boolean expression and returns the message and result
* of the expression. Messages in the messageMap can
* also contain VTL (Velocity Template Language) but without any VTL keys
* Note: Order of boolean operation: ANDs before ORs and operations
* inside parentheses before anything else.
* Example 1: 'A AND B OR C AND D' internally evaluates to '(A AND B) OR (C AND D)'
* booleanExpression = "A*B+C*D"
* Example 2: '(M1 AND M2) OR M3'
* booleanExpression = "(M1*M2)+M3"
*
* @param booleanExpression Boolean expression
* @param messageMap Contains a map of messages (or VTL)
* @return Boolean function result
*/
public BooleanFunctionResult build(
final String booleanExpression,
final Map messageMap) {
this.booleanExpression = booleanExpression;
this.messageMap = messageMap;
return build();
}
/**
* Builds and evaluates a boolean expression and returns the message and result
* of the expression. Messages in the messageMap can
* also contain VTL (Velocity Template Language).
* messageContextMap contains Velocity key/value entries
* referenced in the messageMap.
* Note: Order of boolean operation: ANDs before ORs and operations
* inside parentheses before anything else.
* Example 1: 'A AND B OR C AND D' internally evaluates to '(A AND B) OR (C AND D)'
* booleanExpression = "A*B+C*D"
* Example 2: '(M1 AND M2) OR M3'
* booleanExpression = "(M1*M2)+M3"
*
*
* @param booleanExpression Boolean expression
* @param messageMap Contains a map of messages (or VTL)
* @param messageContextMap Message contact map for Velocity Template Engine
* @return Boolean function result
* @throws MessageBuilderException Errors building message
*/
public BooleanFunctionResult build(
final String booleanExpression,
final Map messageMap,
final Map messageContextMap) {
this.booleanExpression = booleanExpression;
this.messageMap = messageMap;
this.messageContextMap = messageContextMap;
return build();
}
public BooleanFunctionResult build() {
BinaryMessageTree astTree = null;
try {
// set the functionString and Maps from the proposition container
Map nodeMessageMap = buildMessageMap();
// go parse function in buildTree
astTree = new BinaryMessageTree(this.language, nodeMessageMap);
BooleanNode root = astTree.buildTree(this.booleanExpression);
astTree.traverseTreePostOrder(root, null);
List treeNodes = astTree.getAllNodes();
// tree node order in the list is important for building
// the success and failure message
this.treeNodeMessageBuilder.buildMessage(treeNodes);
} catch(VelocityException e) {
throw new MessageBuilderException("Building Velocity message failed: " + e.getMessage(), e);
} catch (BooleanFunctionException e) {
throw new MessageBuilderException("Building message failed: " + e.getMessage(), e);
}
// This is the final rule report message summary
String message = astTree.getRoot().getNodeMessage();
Boolean result = astTree.getRoot().getValue();
// Removed starting and ending brackets if they are the only brackets in the message
if (message.startsWith("(") && message.endsWith(")") &&
message.replaceAll("[^(]","").length() == 1 &&
message.replaceAll("[^)]","").length() == 1) {
message = message.substring(1, message.length()-1);
}
return new BooleanFunctionResult(this.booleanExpression, result, message);
}
/**
* Builds message map. Also builds message map using velocity templates.
*
* @return Boolean message map
*/
private Map buildMessageMap() {
Map nodeMessageMap = new HashMap();
if (this.booleanExpression == null || this.booleanExpression.isEmpty()) {
throw new MessageBuilderException("Boolean expression is null");
}
BooleanFunction func = new BooleanFunction(this.booleanExpression);
List funcVars = func.getVariables();
if(funcVars == null || funcVars.isEmpty()) {
throw new MessageBuilderException("Boolean function variables are null or empty. Boolean expression: " + this.booleanExpression);
}
for (String id : funcVars) {
if(id == null) {
throw new MessageBuilderException("Boolean variable id is null or empty. Boolean variable ids: " + funcVars);
}
BooleanMessage message = this.messageMap.get(id);
if (message == null) {
throw new MessageBuilderException("Boolean message is null for id='" + id + "'");
}
BooleanMessage booleanMessage = buildMessage(message);
nodeMessageMap.put(id, booleanMessage);
}
return nodeMessageMap;
}
/**
* Builds a failure/success message using the Velocity template engine.
*
* @param message Boolean failure/success message
* @return
*/
private BooleanMessage buildMessage(BooleanMessage message) {
String msg = message.getMessage();
if(msg != null) {
msg = this.templateEngine.evaluate(this.messageContextMap, msg);
}
return new BooleanMessageImpl(message.getMessageId(), message.isSuccesful(), msg);
}
}