scriptella.core.ContentExecutor Maven / Gradle / Ivy
/*
* Copyright 2006-2012 The Scriptella Project Team.
*
* Licensed 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 scriptella.core;
import scriptella.configuration.ContentEl;
import scriptella.configuration.IncludeEl;
import scriptella.configuration.Location;
import scriptella.configuration.ScriptingElement;
import scriptella.expression.PropertiesSubstitutor;
import scriptella.spi.Connection;
import scriptella.spi.DialectIdentifier;
import scriptella.spi.Resource;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Base class for Script/Query executors.
*
* @author Fyodor Kupolov
* @version 1.0
*/
abstract class ContentExecutor implements ExecutableElement {
private Resource cachedContent; //initialized on the first execution
private T element;
private PropertiesSubstitutor contentPropsSubstitutor;
protected final Logger log = Logger.getLogger(getClass().getName());
protected final boolean debug = log.isLoggable(Level.FINE);
/**
* Initializes and stores reference to script element.
*
* @param scriptingElement query or script.
*/
protected ContentExecutor(T scriptingElement) {
this.element = scriptingElement;
}
/**
* Returns scripting element specified in {@link #ContentExecutor constructor}
*
* @return scripting element
*/
public T getElement() {
return element;
}
public final void execute(final DynamicContext ctx) {
final Connection c = ctx.getConnection();
final Resource content = getContent(c.getDialectIdentifier());
if (content == ContentEl.NULL_CONTENT && debug) {
log.fine("Element " + getLocation() + " has no supported dialects, no content executed.");
}
try {
//Set parameters if content is dynamic
if (contentPropsSubstitutor != null) { //If initialized
contentPropsSubstitutor.setParameters(ctx);
}
execute(c, content, ctx);
} finally {
//Clear the parameters if initialized
if (contentPropsSubstitutor != null) {
contentPropsSubstitutor.setParameters(null);
}
}
}
/**
* Executes a script or a query resource using the specified connection.
*
* @param connection connection to use for element execution.
* @param resource query/script content to execute.
* @param ctx dynamic context to use for variables, etc.
*/
protected abstract void execute(final Connection connection, final Resource resource, final DynamicContext ctx);
/**
* Returns content satisfying dialect information.
* This method caches contents based on dialects.
* For now we assume dialectIdentifier is constant for element.
*
* @param dialectIdentifier dialect identifier.
* @return content for dialect. Not null.
*/
public Resource getContent(DialectIdentifier dialectIdentifier) {
if (cachedContent == null) {
cachedContent = prepareContent(element.getDialectContent(dialectIdentifier));
}
if (cachedContent == null) { //avoid double initialization
cachedContent = ContentEl.NULL_CONTENT;
}
return cachedContent;
}
/**
* A short for {@link #getElement()}.{@link scriptella.configuration.ScriptingElement#getLocation() getLocation()}
*
* @return element location.
*/
public Location getLocation() {
return getElement().getLocation();
}
/**
* Prepares the content for later execution.
*
If content is dynamic, i.e. contains includes with bind variables, the properties substitutor is specified,
* otherwise no properties .
*
* @param content content to traverse.
* @return the same content object for convenience only.
*/
protected ContentEl prepareContent(ContentEl content) {
if (content == null) {
return null;
}
for (Resource resource : content.getResources()) {
if (resource instanceof IncludeEl) {
IncludeEl include = (IncludeEl) resource;
//Performance optimization: check if href contains properties
if (PropertiesSubstitutor.hasProperties(include.getHref())) {
if (contentPropsSubstitutor == null) { //Lazily initialize the substitutor
contentPropsSubstitutor = new PropertiesSubstitutor();
}
include.setPropertiesSubstitutor(contentPropsSubstitutor);
}
}
}
return content;
}
}