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StandardScriptUtils.retrieveEngineByName for lookup with descriptive exception message

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Also revised StandardScriptFactory for finer-grained template methods, added further configuration variants to StandardScriptEvaluator, and identified thread-local ScriptEngine instances in ScriptTemplateView by appropriate key.

Issue: SPR-13491
Issue: SPR-13487
This commit is contained in:
Juergen Hoeller
2015-09-23 22:37:35 +02:00
parent fe3aad4ab2
commit c7fd4ccf48
4 changed files with 278 additions and 96 deletions
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75
spring-webmvc/src/main/java/org/springframework/web/servlet/view/script/ScriptTemplateView.java
View File

@@ -22,6 +22,8 @@ import java.net.URL;
import java.net.URLClassLoader;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.script.Invocable;
@@ -39,8 +41,10 @@ import org.springframework.core.NamedThreadLocal;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.scripting.support.StandardScriptUtils;
import org.springframework.util.Assert;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.view.AbstractUrlBasedView;
@@ -57,6 +61,7 @@ import org.springframework.web.servlet.view.AbstractUrlBasedView;
* {@link ScriptTemplateConfigurer#setSharedEngine(Boolean)} for more details.
*
* @author Sebastien Deleuze
* @author Juergen Hoeller
* @since 4.2
* @see ScriptTemplateConfigurer
* @see ScriptTemplateViewResolver
@@ -69,8 +74,9 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
private static final String DEFAULT_RESOURCE_LOADER_PATH = "classpath:";
private static final ThreadLocal<ScriptEngine> engineHolder =
new NamedThreadLocal<ScriptEngine>("ScriptTemplateView engine");
private static final ThreadLocal<Map<Object, ScriptEngine>> enginesHolder =
new NamedThreadLocal<Map<Object, ScriptEngine>>("ScriptTemplateView engines");
private ScriptEngine engine;
@@ -87,9 +93,11 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
private Charset charset;
private String resourceLoaderPath;
private ResourceLoader resourceLoader;
private String resourceLoaderPath;
private volatile ScriptEngineManager scriptEngineManager;
/**
@@ -234,12 +242,20 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
Assert.isTrue(this.renderFunction != null, "The 'renderFunction' property must be defined.");
}
protected ScriptEngine getEngine() {
if (Boolean.FALSE.equals(this.sharedEngine)) {
ScriptEngine engine = engineHolder.get();
Map<Object, ScriptEngine> engines = enginesHolder.get();
if (engines == null) {
engines = new HashMap<Object, ScriptEngine>(4);
enginesHolder.set(engines);
}
Object engineKey = (!ObjectUtils.isEmpty(this.scripts) ?
new EngineKey(this.engineName, this.scripts) : this.engineName);
ScriptEngine engine = engines.get(engineKey);
if (engine == null) {
engine = createEngineFromName();
engineHolder.set(engine);
engines.put(engineKey, engine);
}
return engine;
}
@@ -250,21 +266,22 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
}
protected ScriptEngine createEngineFromName() {
ScriptEngine engine = new ScriptEngineManager().getEngineByName(this.engineName);
if (engine == null) {
throw new IllegalStateException("No engine with name '" + this.engineName + "' found");
if (this.scriptEngineManager == null) {
this.scriptEngineManager = new ScriptEngineManager(getApplicationContext().getClassLoader());
}
ScriptEngine engine = StandardScriptUtils.retrieveEngineByName(this.scriptEngineManager, this.engineName);
loadScripts(engine);
return engine;
}
protected void loadScripts(ScriptEngine engine) {
if (this.scripts != null) {
if (!ObjectUtils.isEmpty(this.scripts)) {
try {
for (String script : this.scripts) {
Resource resource = this.resourceLoader.getResource(script);
if (!resource.exists()) {
throw new IllegalStateException("Resource " + script + " not found");
throw new IllegalStateException("Script resource [" + script + "] not found");
}
engine.eval(new InputStreamReader(resource.getInputStream()));
}
@@ -309,6 +326,7 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
}
}
@Override
protected void prepareResponse(HttpServletRequest request, HttpServletResponse response) {
super.prepareResponse(request, response);
@@ -326,6 +344,7 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
Invocable invocable = (Invocable) engine;
String url = getUrl();
String template = getTemplate(url);
Object html;
if (this.renderObject != null) {
Object thiz = engine.eval(this.renderObject);
@@ -334,6 +353,7 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
else {
html = invocable.invokeFunction(this.renderFunction, template, model, url);
}
response.getWriter().write(String.valueOf(html));
}
catch (Exception ex) {
@@ -347,4 +367,39 @@ public class ScriptTemplateView extends AbstractUrlBasedView {
return FileCopyUtils.copyToString(reader);
}
/**
* Key class for the {@code enginesHolder ThreadLocal}.
* Only used if scripts have been specified; otherwise, the
* {@code engineName String} will be used as cache key directly.
*/
private static class EngineKey {
private final String engineName;
private final String[] scripts;
public EngineKey(String engineName, String[] scripts) {
this.engineName = engineName;
this.scripts = scripts;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof EngineKey)) {
return false;
}
EngineKey otherKey = (EngineKey) other;
return (this.engineName.equals(otherKey.engineName) && Arrays.equals(this.scripts, otherKey.scripts));
}
@Override
public int hashCode() {
return (this.engineName.hashCode() * 29 + Arrays.hashCode(this.scripts));
}
}
}