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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Digital Signal Processing A Practical Guide for Engineers and Scientists

by [Smith, Steven]

$114.80

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Description

This immensely practical and thorough book has been written for engineers and scientists in a wide variety of fields, with the goal of explaining DSP techniques while avoiding the barriers of abstract theory and detailed mathematics, enabling readers to put the powerful tools of DSP to work in their research and designs. All techniques are explained through analogies, not simply proven to be true through mathematical derivations. The math is included where it is needed, but it is not used as the primary means of conveying the information. The illustrations are profuse and help to support the text in creative ways. Numerous detailed applications examples from many fields bring the theory to life. The coverage is thorough, detailed, and enlightening. The accompanying CD-ROM contains all the computer code from the 40+ programs used in the applications examples, along with DSP software tools and info from various DSP manufacturers.

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Product Details

  • Newnes Brand
  • 9780750674447 ISBN-13:
  • 075067444X ISBN-10:
  • 650.0 pages Paperback
  • 075067444X Contents same as book with US ISBN
  • 9780750674447 Contents same as book with US ISBN-13
  • 813120328X ISBN
  • New Condition
  • Paperback, Printed in Grayscale Media
  • 1 business day Generally Ships in
  • International Edition Media
  • 9.96 in * 1.15 in * 7.26 in Dimensions:
  • 1 lb Weight: