/* ZScript.java
Purpose:
Description:
History:
Thu Jun 2 10:46:03 2005, Created by tomyeh
Copyright (C) 2005 Potix Corporation. All Rights Reserved.
{{IS_RIGHT
This program is distributed under LGPL Version 2.1 in the hope that
it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.zk.ui.metainfo;
import java.net.URL;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.zkoss.util.resource.ContentLoader;
import org.zkoss.util.resource.Locator;
import org.zkoss.util.resource.ResourceCache;
import org.zkoss.zk.scripting.Interpreters;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.Page;
import org.zkoss.zk.ui.UiException;
import org.zkoss.zk.xel.EvaluatorRef;
import org.zkoss.zk.xel.ExValue;
/**
* Represents a zscript content.
*
* @author tomyeh
*/
public class ZScript implements java.io.Serializable {
private static final Logger log = LoggerFactory.getLogger(ZScript.class);
private EvaluatorRef _evalr;
private String _zslang;
private final String _cnt;
/** An URL, an ExValue. */
private final Object _url;
private final Locator _locator;
/** Parses the content into a {@link ZScript} instance.
*
* <p>This method assumes the content is in the following format:<br/>
* <code>lang:codes</code><br/>
* <code>codes</code>
*
* <p>For example, "javascript:var m = 0;" returns "javascript", while
* "var m = 0;" returns null.
*
* <p>Note: if the language doesn't exist, null is returned.
* Reason: the above syntax may be conflict with some scripting languages.
*
* <p>Note: no space is allowed.
*
* @param content the content of zscript codes
* @since 3.0.0
*/
public static final ZScript parseContent(String content) {
return parseContent(content, 0);
}
/** Parses the content into a {@link ZScript} instance.
*
* <p>It is similar to {@link #parseContent(String)} except it
* allows the caller to specify the line number of the first line of the
* content.
*
* @param content the content of zscript codes
* @param lineno the line number of the first line. Ignored if
* zero (or negative).
* @since 3.6.1
*/
public static final ZScript parseContent(String content, int lineno) {
String prefix = null, zslang = null;
final int len = content != null ? content.length() : 0;
if (len > 0) {
//Don't generate prefix if content is empty (i.e., keep empty)
//so PageImpl.interpret() could optimize it (not to execute at all)
if (lineno > 1) {
final StringBuffer sb = new StringBuffer(lineno);
while (--lineno > 0)
sb.append('\n');
prefix = sb.toString();
}
for (int j = 0; j < len; ++j) {
final char cc = content.charAt(j);
if (cc == ':') {
if (j > 0) {
zslang = content.substring(0, j);
if (Interpreters.exists(zslang)) {
content = content.substring(j + 1);
break;
} else {
log.warn("Ignored: unknown scripting language, " + zslang);
}
}
break;
}
if (!Interpreters.isLegalName(cc)) {
break; //done
}
}
}
return new ZScript(zslang, prefix != null && content.length() > 0 ? prefix + content : content);
}
/** Creates a zscript with the content directly.
*
* @param zslang the scripting language. If null, it is the same as
* {@link org.zkoss.zk.ui.Page#getZScriptLanguage}.
* @param content the zscript content
* @see #parseContent
*/
public ZScript(String zslang, String content) {
_zslang = zslang;
_cnt = content != null ? content : "";
_url = null;
_locator = null;
}
/** Creates a zscript with an URL that is used to load the content.
*/
public ZScript(String zslang, URL url) {
if (url == null)
throw new IllegalArgumentException("null");
_zslang = zslang;
_url = url;
_cnt = null;
_locator = null;
}
/** Creates a zscript with an URL that is used to load the content.
* @param evalr the evaluator used to evaluate
* @exception IllegalArgumentException if url or locator is null, or
* url contains EL and evalr is null.
*/
public ZScript(EvaluatorRef evalr, String zslang, String url, Locator locator) {
if (url == null || locator == null)
throw new IllegalArgumentException("null");
//TODO: use url's extension to determine zslang
_evalr = evalr;
_zslang = zslang;
_url = new ExValue(url, String.class);
_cnt = null;
_locator = locator;
if (evalr == null && ((ExValue) _url).isExpression())
throw new IllegalArgumentException("evalr required since EL is used: " + url);
}
/** Returns the scripting language, or null if the default scripting language
* is preferred.
*/
public String getLanguage() {
return _zslang;
}
/** Sets the scripting language.
*
* @param zslang the scripting language. If null, the default scripting
* language is assume.
*/
public void setLanguage(String zslang) {
_zslang = zslang;
}
/** Returns the raw content.
* It is the content specified in the constructor
* ({@link #ZScript(String, String)}.
* If URL is specified in the constructor, null is returned.
*
* <p>On the other hand, {@link #getContent} will load the content
* automatically if URL is specified.
*
* @return the raw content specified in the constructor, or null
* if URL is specified instead.
*/
public String getRawContent() {
return _cnt;
}
/** Returns the content of zscript.
* If URL is specified, this method loads the content from it.
* If URL is an EL expression, it will be evaluated first.
*
* @param page the page when this zscript is interpreted.
* Used only if this object is constructed with {@link #ZScript(EvaluatorRef, String, String, Locator)}.
* @param comp the component when this zscript is interpreted.
* Used only if this object is constructed with {@link #ZScript(EvaluatorRef, String, String, Locator)}.
* @exception UiException if failed to load the content
*/
public String getContent(Page page, Component comp) {
if (_cnt != null)
return _cnt;
final URL url;
if (_url instanceof ExValue) {
final String s = (String) (comp != null ? ((ExValue) _url).getValue(_evalr, comp)
: ((ExValue) _url).getValue(_evalr, page));
if (s == null || s.length() == 0)
throw new UiException("The zscript URL, " + _url + ", is evaluated to \"" + s + '"');
url = _locator.getResource(s);
if (url == null)
throw new UiException("File not found: " + s + " (evaluated from " + _url + ')');
//note: we don't throw FileNotFoundException since Tomcat 'eats' it
} else {
url = (URL) _url;
}
final String o = getCache().get(url);
//It is OK to use cache here even if script might be located, say,
//at a database. Reason: it is Locator's job to implement
//the relevant function for URL (including lastModified).
if (o == null)
throw new UiException("File not found: " + _url);
//note: we don't throw FileNotFoundException since Tomcat 'eats' it
return o;
}
/** Sets the evaluator reference.
*/
/*package*/ void setEvaluatorRef(EvaluatorRef evalr) {
_evalr = evalr;
}
//Object//
public String toString() {
final StringBuffer sb = new StringBuffer(40).append("[zscript: ");
if (_url != null) {
sb.append(_url);
} else {
final int len = _cnt.length();
if (len > 20) {
sb.append(_cnt.substring(0, 16)).append("...");
} else {
sb.append(_cnt);
}
}
return sb.append(']').toString();
}
private static volatile ResourceCache<Object, String> _cache;
private static final ResourceCache<Object, String> getCache() {
if (_cache == null) {
synchronized (ZScript.class) {
if (_cache == null) {
final ResourceCache<Object, String> cache = new ResourceCache<Object, String>(new ContentLoader());
cache.setMaxSize(512);
cache.setLifetime(60 * 60 * 1000); //1hr
_cache = cache;
}
}
}
return _cache;
}
}