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--- a/trunk/php-java-bridge/FAQ.html +++ b/trunk/php-java-bridge/FAQ.html @@ -5,12 +5,12 @@ <TITLE>PHP/ Java Bridge FAQ</TITLE> </HEAD> <H1>PHP/Java Bridge FAQ</H1> -This file contains answers to frequently asked questions. +This file contains answers to frequently asked questions. Please see <a href="http://php-java-bridge.sourceforge.net/pjb">http://php-java-bridge.sourceforge.net</a> for more information. <H2>General questions about the C- or pure PHP implementation</H2> -<H4>Do I need a Java Application server or Servlet engine?</H4> -<p>No. The bridge and the VM can run as a sub component of IIS or Apache. The C based extension automatically starts a VM in the <code>minit()</code> and terminates it in the <code>mshutdown()</code> hook. The request-handling threads attach themselfs to the VM (using the PHP/Java Bridge protocol) to execute Java methods. +<H4>Do I need a Java Application Server or Servlet Engine?</H4> +<p>No. The bridge and the VM can run as a sub component of IIS or Apache. The C based extension automatically starts a VM in the <code>minit()</code> and terminates it in the <code>mshutdown()</code> hook. The request-handling threads attach themselfs to the persistent VM using the PHP/Java Bridge protocol. <p> <H4>What's the advantage/disadvantage of the pure PHP implementation?</H4> <p>Both implementations support the same features. But since PHP doesn't contain a "just in time compiler", the C based extension module is 2 to 10 times faster than the the pure PHP implementation (depending on whether a PHP opcode cache is used). @@ -18,32 +18,74 @@ <p>The pure PHP implementation needs an external Java process. It can be started with <code>java -jar JavaBridge.jar SERVLET:8080</code>, but it is recommended to start the external Java VM via a J2EE server or servlet engine. The tomcat servlet engine can be used to start Java as a system service on Windows and Linux. </p> <p> -The C based implementation compiles and works on all operating systems, including Windows, see the INSTALL document for details. But we cannot provide binaries for all operating systems. If you cannot compile C code, use the pure PHP implementation instead. +The C based implementation compiles and works on all operating systems, including Windows. But we cannot provide binaries for all operating systems. If you cannot compile C code, use the pure PHP implementation instead. </p> <H4>Why is Java.inc obfuscated?</H4> <p>The pure PHP implementation contained in <code>Java.inc</code> is created during compilation from the other *.inc files located in the java folder. Since some older PHP implementations don't have a opcode cache (sometimes called "accelerator"), we have removed all comments and white space from the source files. Use <blockquote> <code> - require_once("http://localhost:8080/java/JavaBridge.inc"; + require_once("http://localhost:8080/JavaBridge/java/JavaBridge.inc"; </code> </blockquote> if you want to run the original code.</p> <H4>Can I use Java libraries without installing java?</H4> <p>Yes. Simply compile the C based extension and omit the -<code>--with-java=</code> configure option. The <a href="README.GNU_JAVA">bridge will use the -<code>libgcj</code> library</a>, which is part of the GNU gcc compiler. This library also uses much less system +<code>--with-java=</code> configure option. The bridge will use the +<code>libgcj</code> library, which is part of the GNU gcc compiler. This library also uses much less system resources (memory, files) than a "real" Java VM.</p> <H4>Can I compile the C code without compiling the Java classes to native code?</H4> <p>Yes. If your C compiler cannot compile Java classes to native code, use the <code>--disable-backend</code> configure option and add a <code>java.java=/path/to/your/java/executable</code> option to your php.ini <code>[java]</code> section.</p> <H4>Can I use Python instead of PHP?</H4> <p>Yes, see the examples folder from the source download.</p> <H4>Can I access Mono or .NET libraries using the pure PHP implementation?</H4> <p>No. You need to compile the C implementation and use the configure option <code>--with-mono</code>.</p> -<H4>Where is my output?</H4> <p><code>System.out</code> and <code>System.err</code> are redirected to the server log file(s). When PHP scripts are invoked from a java framework (Java Server Faces for example), even the PHP output is redirected. For the standalone back end the output appears in the <code>/var/log/php-java-bridge.log</code> or in JavaBridge.log, see .ini option <code>java.log_file</code>. For the j2ee back end the location of the log file(s) depends on the j2ee server configuration.</p> - <H4>How can I configure the bridge?</H4> <p>The three config options <code>java.log_level</code>, <code>java.servlet</code> and <code>java.hosts</code> can be changed in the <code>php.ini</code> file (C based implementation) or <code>Java.inc</code>, which is created from <code>Options.inc</code> (pure PHP implementation). +<H4>What if the Java back end is not available anymore?</H4> + +<p> +Then the bridge uses the next entry from the <code>java.hosts</code> +list. If there are no more entries, the php function java_server_name() +returns null and all other java procedures cannot be used anymore. +</p> + +<H4>Can I set the java.hosts option at run-time?</H4> + +<p>Yes. The bridge examines the environment variables +<code>X_JAVABRIDGE_OVERRIDE_HOSTS</code> and +<code>X_JAVABRIDGE_OVERRIDE_HOSTS_REDIRECT</code>. +</p> +<p>To direct a php script to a web context FOO running on computer +192.168.4.98, port 8080, use the following code: + +<blockquote> <code> <?php<br> + $_SERVER['X_JAVABRIDGE_OVERRIDE_HOSTS_REDIRECT']="h:192.168.4.98:8080//FOO/JavaBridge.phpjavabridge";<br> + echo java_server_name();<br> + ?> </code> </blockquote> + +Assuming that the option <code>java.servlet</code> or +<code>JAVA_SERVLET</code> (pure PHP implementation) is set to +<code>On</code>, the above example uses plain HTTP to connect to the +server 192.168.4.98 on port 8080 using the web context FOO. If PHP has +been compiled with openssl enabled, <code>s:..</code> can be used to +connect to a SSL port. When <code>java.servlet</code> or +<code>JAVA_SERVLET</code> is set to <code>User</code> or +<code>Off</code>, the bridge ignores the specified <code>FOO</code> +context and uses the request context instead, or it connects to a +standalone socket listener directly (if the option is Off). +</p> +<p> +To direct a php instance to a to a web context FOO running on computer +192.168.4.98, port 8080, use the variable +<code>X_JAVABRIDGE_OVERRIDE_HOSTS</code> instead. This variable must +be set before the PHP instance starts. +</p> +<p> +When <code>X_JAVABRIDGE_OVERRIDE_HOSTS_REDIRECT</code> is used and +the php instance already has a persistent connection to another host, +it opens a second persistent connection to the new host. +</p> <H2>Running Java as a sub component of Apache or IIS</H2> @@ -77,10 +119,17 @@ <p> With <code>java_require("foo.jar;bar.jar, ...");. See the README for details.</p> <H4>Why can't Apache load my /foo/bar/baz.jar file?</H4> -<p>It probably doesn't have the permission to access it. Try to disable Security Enhanced Linux and store the jar file into a folder accessible by the apache user and then extract the required Security Enhanced Linux permissions from the audit log.</p> +<p>It probably doesn't have the permission to access it. Check if +baz.jar is a valid Java archive and if its main class is public. Try +to disable Security Enhanced Linux and store the jar file into a +folder accessible by the apache user and then extract the required +Security Enhanced Linux permissions from the audit log.</p> <H4>Why do I get a ClassNotFoundException?</H4> -<p>You probably haven't required the relevant Java library. Check which library exports the feature and add the library to the <code>java_require()</code> statement.</code></p> +<p>You probably haven't required the relevant Java library. Or the +class doesn't exist or it is not public or it throws a java.lang.Error +during initialization. Check which library exports the feature and add +the library to the <code>java_require()</code> statement.</code></p> <H4>Why do I get a NoClassDefFoundError?</H4> <p>Because Java doesn't have a module system. All interconnected libraries must be loaded with a single <code>java_require()</code> call. See the README for details.</p> @@ -89,9 +138,9 @@ <p>The <code>java_require()</code> uses the current class loader, not the bootstrap loader. Use: <blockquote> <code> - java_require("foo.jar");<br> - ...<br> - Class.forName("foo",true,Thread.currentThread().getContextClassLoader());<br> + java_require("foo.jar");<br> + ...<br> + Class.forName("foo",true,Thread.currentThread().getContextClassLoader());<br> </code> </blockquote> instead. @@ -451,6 +500,34 @@ <H2>General runtime questions</H2> +<H4>How can is access the Servlet, ServletContext or ServletRequest from a remote PHP script?</H4> +<p> +Unless you write your own servlet, you can't. The default +implementation of the PhpJavaServlet does not wait for a +RemoteServletContextFactory to finish because it cannot reliably determine if a +remote script terminated or not. +</p> +<p>If you can provide this information, override the PhpJavaServlet's +<code>getContextFactory()</code>. Provide your own +RemoteServletContextFactory and create a custom Context in your +<code>createContext()</code> method. Then wait for the context by +overriding the <code>waitForContext() method.</code>. Ask yourself how +to handle a situation where a script asks for a context but doesn't +do anything with it, for example: <code><?php java_context(); +?></code>. Is it okay that the servlet waits 10 minutes until the +orphaned context is destroyed? +<p> + +<H4>Where is my output?</H4> <p><code>System.out</code> and +<code>System.err</code> are redirected to the server log file(s). When +PHP scripts are invoked from a java framework (Java Server Faces for +example), even the PHP output is redirected. For the standalone back +end the output appears in the +<code>/var/log/php-java-bridge.log</code> or in JavaBridge.log, see +.ini option <code>java.log_file</code>. For the j2ee back end the +location of the log file(s) depends on the j2ee server +configuration.</p> + <H4>How do I make my script state (objects or variables) persistent?</H4> <p>If you must code it yourself: with @@ -462,7 +539,9 @@ href="documentation/PHP-API/html/java_8c.html#doc25">java_session()<a></code> internaly. If you don't want depend on the PHP session module, for example if you have compiled PHP without the <code>session.so</code>, -use java_session() instead.</p> <p> If you use the <a +use java_session() instead.</p> +<!-- +<p> If you use the <a href="http://www.jcp.org/en/jsr/detail?id=127">Java Server Faces</a> framework, you declare the scope of the script in the <a href="server/WEB-INF/faces-config.xml">PHP @@ -471,6 +550,7 @@ to <code>session</code>, the framework automatically saves the state of the PHP script instance and restores it when the next request belonging to the same session comes in.</p> +--> <H4>How many threads does the bridge start?</H4> <p>Request-handling threads are started @@ -496,9 +576,9 @@ With the <code>classname$inner</code> syntax. For example <br><br> <code> public interface php {<br> - public class java {<br> - public enum bridge {JavaBridge, JavaBridgeRunner};<br> - }<br> + public class java {<br> + public enum bridge {JavaBridge, JavaBridgeRunner};<br> + }<br> }<br> </code><br> can be accessed with:<br><br> @@ -542,8 +622,8 @@ $i=0;<br> java_begin_document();<br> while($i<400000) {<br> - $i=$i+1;<br> - $buf->append(new java("java.lang.String", $String->valueOf($i)));<br> + $i=$i+1;<br> + $buf->append(new java("java.lang.String", $String->valueOf($i)));<br> }<br> java_end_document();<br> <br> @@ -558,8 +638,8 @@ <br> int i=0;<br> while(i<400000) {<br> - i=i+1;<br> - buf.append(new String(String.valueOf(i)));<br> + i=i+1;<br> + buf.append(new String(String.valueOf(i)));<br> }<br> <br> print (buf.length()); print("\n");<br> @@ -645,6 +725,7 @@ </p> <p> </p> +<!-- <H4>How do I start a persistent VM?</H4> <p> If you want to start <em>one persistent VM per HTTP server</em> running on a computer, see @@ -653,20 +734,19 @@ </p> <p>Furthermore it is possible to start a standalone back end, for example with the command:<br><br> <code> - java -jar JavaBridge.jar INET_LOCAL:9676 3<br> + java -jar JavaBridge.jar INET_LOCAL:9676 3<br> </code> <br> The <code>php.ini</code> entry might look like:<br><br> <code> - [java]<br> - java.hosts = 127.0.0.1:9676<br> - java.servlet = Off<br> + [java]<br> + java.hosts = 127.0.0.1:9676<br> + java.servlet = Off<br> </code> <br> Please see the <a href="server/documentation/API/php/java/bridge/JavaBridge.html">JavaBridge</a> documentation for details. </p> -<!-- AS test ports (Sun Mar 16 09:54:17 CET 2003, Jost Boekemeier) * Oracle: http://localhost:8888/ @@ -719,10 +799,10 @@ With <code>java_begin_document()/java_end_document()</code>. For example: <blockquote> <code> - java_begin_document();<br> - $s = new Java("java.lang.StringBuffer");<br> - for($i=0; $i<10000; $i++) $s->append($i);<br> - java_end_document();<br> + java_begin_document();<br> + $s = new Java("java.lang.StringBuffer");<br> + for($i=0; $i<10000; $i++) $s->append($i);<br> + java_end_document();<br> </code> </blockquote> The above code sends the PHP code as an XML image to the server and executes it there. @@ -732,10 +812,10 @@ With <code>java_values()</code>. For example: <blockquote> <code> - $s = new Java("java.lang.String");<br> - $c = $chr = $s->toCharArray();<br> - print (java_values($s));<br> - print_r(java_values($c));<br> + $s = new Java("java.lang.String");<br> + $c = $chr = $s->toCharArray();<br> + print (java_values($s));<br> + print_r(java_values($c));<br> </code> </blockquote> </p> @@ -744,13 +824,13 @@ With <code>java_closure()</code>. For example: <blockquote> <code> - class Foo {<br> - function toString() {return "php::foo";}<br> - }<br> - $foo = new Foo();<br> - $jObj = java_closure($foo);<br> - $String = new Java("java.lang.String");<br> - echo $String->valueOf($jObj);<br> + class Foo {<br> + function toString() {return "php::foo";}<br> + }<br> + $foo = new Foo();<br> + $jObj = java_closure($foo);<br> + $String = new Java("java.lang.String");<br> + echo $String->valueOf($jObj);<br> </code> </blockquote> </p>
/trunk/php-java-bridge/server/php/java/bridge/http/ContextFactory.java Diff Switch to side-by-side view
/trunk/php-java-bridge/server/php/java/bridge/http/IContextFactory.java Diff Switch to side-by-side view
