FreeMarker template error: The following has evaluated to null or missing: ==> [in template "component://snj2/template/catalog/ProductDetail.ftl" at line 389, column 19] ---- Tip: It's the step after the last dot that caused this error, not those before it. ---- Tip: If the failing expression is known to be legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? ---- ---- FTL stack trace ("~" means nesting-related): - Failed at: #if (product.originalImageUrl?string?... [in template "component://snj2/template/catalog/ProductDetail.ftl" at line 389, column 13] ---- Java stack trace (for programmers): ---- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134) at freemarker.core.UnexpectedTypeException.newDesciptionBuilder(UnexpectedTypeException.java:80) at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:43) at freemarker.core.BuiltInsForMultipleTypes$stringBI._eval(BuiltInsForMultipleTypes.java:709) at freemarker.core.Expression.eval(Expression.java:81) at freemarker.core.ExistenceBuiltins$ExistenceBuiltIn.evalMaybeNonexistentTarget(ExistenceBuiltins.java:52) at freemarker.core.ExistenceBuiltins$has_contentBI._eval(ExistenceBuiltins.java:112) at freemarker.core.ExistenceBuiltins$has_contentBI.evalToBoolean(ExistenceBuiltins.java:119) at freemarker.core.AndExpression.evalToBoolean(AndExpression.java:36) at freemarker.core.ParentheticalExpression.evalToBoolean(ParentheticalExpression.java:35) at freemarker.core.IfBlock.accept(IfBlock.java:49) at freemarker.core.Environment.visit(Environment.java:326) at freemarker.core.Environment.visit(Environment.java:332) at freemarker.core.Environment.visit(Environment.java:332) at freemarker.core.Environment.process(Environment.java:305) at org.apache.ofbiz.base.util.template.FreeMarkerWorker.renderTemplate(FreeMarkerWorker.java:263) at org.apache.ofbiz.widget.model.HtmlWidget.renderHtmlTemplate(HtmlWidget.java:167) at org.apache.ofbiz.widget.model.HtmlWidget$HtmlTemplate.renderWidgetString(HtmlWidget.java:216) at org.apache.ofbiz.widget.model.HtmlWidget.renderWidgetString(HtmlWidget.java:140) at org.apache.ofbiz.widget.model.ModelScreenWidget$PlatformSpecific.renderWidgetString(ModelScreenWidget.java:1321) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$Section.renderWidgetString(ModelScreenWidget.java:280) at org.apache.ofbiz.widget.model.ModelScreen.renderScreenString(ModelScreen.java:164) at org.apache.ofbiz.widget.model.ScreenFactory.renderReferencedScreen(ScreenFactory.java:214) at org.apache.ofbiz.widget.model.ModelScreenWidget$IncludeScreen.renderWidgetString(ModelScreenWidget.java:780) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$Section.renderWidgetString(ModelScreenWidget.java:280) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$DecoratorSection.renderWidgetString(ModelScreenWidget.java:906) at org.apache.ofbiz.widget.model.ModelScreenWidget$SectionsRenderer.render(ModelScreenWidget.java:127) at org.apache.ofbiz.widget.model.ModelScreenWidget$DecoratorSectionInclude.renderWidgetString(ModelScreenWidget.java:943) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$Section.renderWidgetString(ModelScreenWidget.java:280) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$Section.renderWidgetString(ModelScreenWidget.java:280) at org.apache.ofbiz.widget.model.ModelScreen.renderScreenString(ModelScreen.java:164) at org.apache.ofbiz.widget.model.ScreenFactory.renderReferencedScreen(ScreenFactory.java:214) at org.apache.ofbiz.widget.model.ModelScreenWidget$DecoratorScreen.renderWidgetString(ModelScreenWidget.java:860) at org.apache.ofbiz.widget.model.ModelScreenWidget.renderSubWidgetsString(ModelScreenWidget.java:98) at org.apache.ofbiz.widget.model.ModelScreenWidget$Section.renderWidgetString(ModelScreenWidget.java:280) at org.apache.ofbiz.widget.model.ModelScreen.renderScreenString(ModelScreen.java:164) at org.apache.ofbiz.widget.renderer.ScreenRenderer.render(ScreenRenderer.java:136) at org.apache.ofbiz.widget.renderer.ScreenRenderer.render(ScreenRenderer.java:98) at org.apache.ofbiz.widget.renderer.macro.MacroScreenViewHandler.render(MacroScreenViewHandler.java:157) at org.apache.ofbiz.webapp.control.RequestHandler.renderView(RequestHandler.java:1001) at org.apache.ofbiz.webapp.control.RequestHandler.doRequest(RequestHandler.java:653) at org.apache.ofbiz.webapp.control.ControlServlet.doGet(ControlServlet.java:213) at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:720) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318) at org.apache.ofbiz.product.category.CatalogUrlServlet.doGet(CatalogUrlServlet.java:153) at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.ofbiz.webapp.control.ContextFilter.doFilter(ContextFilter.java:324) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.ofbiz.content.content.ContentUrlFilter.doFilter(ContentUrlFilter.java:99) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.ofbiz.product.category.CatalogUrlFilter.doFilter(CatalogUrlFilter.java:338) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528) at org.apache.coyote.ajp.AbstractAjpProcessor.process(AbstractAjpProcessor.java:873) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748)
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Understanding Power Quality, Problems: 1st edition

by Math H. J. Bollen

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Description

Power quality problems have increasingly become a substantial concern over the last decade, but surprisingly few analytical techniques have been developed to overcome these disturbances in system-equipment interactions. Now in this comprehensive book, power engineers and students can find the theoretical background necessary for understanding how to analyze, predict, and mitigate the two most severe power disturbances: voltage sags and interruptions. This is the first book to offer in-depth analysis of voltage sags and interruptions and to show how to apply mathematical techniques for practical solutions to these disturbances. From UNDERSTANDING AND SOLVING POWER QUALITY PROBLEMS you will gain important insights into Various types of power quality phenomena and power quality standards Current methods for power system reliability evaluation Origins of voltage sags and interruptions Essential analysis of voltage sags for characterization and prediction of equipment behavior and stochastic prediction Mitigation methods against voltage sags and interruptions" An Instructor Support FTP site is available from the Wiley editorial department: ftp://ftp.ieee.org/uploads/press/bollen Sponsored by: IEEE Power Electronics Society, IEEE Industry Applications Society, IEEE Power Engineering Society.

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  • 0780347137 ISBN-10:
  • 9780780347137 ISBN-13:
  • 9780780347137 ISBN-13
  • 0780347137 ISBN-10
  • New Condition
  • 5 business days Generally Ships in
  • Hardback Media