Abstracted code that parses XML configuration definitions into Java

objects which are then serialized for rapid loading and simple utilization
by the client and server; created serialized config services for our
character component constraints (what components are available at
character creation time, etc.).


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1101 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/tools/CompiledConfigTask.java

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+//
+// $Id: CompiledConfigTask.java,v 1.1 2002/03/08 06:15:21 mdb Exp $
+
+package com.threerings.yohoho.tools;
+
+import java.io.File;
+import java.io.Serializable;
+
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.Task;
+
+import com.threerings.yohoho.tools.xml.CompiledConfigParser;
+import com.threerings.yohoho.util.CompiledConfig;
+
+/**
+ * Used to parse configuration information from an XML file and create the
+ * serialized representation that is used by the client and server.
+ */
+public class CompiledConfigTask extends Task
+{
+    public void setParser (String parser)
+    {
+        _parser = parser;
+    }
+
+    public void setConfigdef (File configdef)
+    {
+        _configdef = configdef;
+    }
+
+    public void setTarget (File target)
+    {
+        _target = target;
+    }
+
+    public void execute () throws BuildException
+    {
+        // instantiate and sanity check the parser class
+        Object pobj = null;
+        try {
+            Class pclass = Class.forName(_parser);
+            pobj = pclass.newInstance();
+        } catch (Exception e) {
+            throw new BuildException("Error instantiating config parser", e);
+        }
+        if (!(pobj instanceof CompiledConfigParser)) {
+            throw new BuildException("Invalid parser class: " + _parser);
+        }
+
+        // make sure the source file exists
+        if (!_configdef.exists()) {
+            String errmsg = "Config definition file not found " +
+                "[path=" + _configdef.getPath() + "]";
+            throw new BuildException(errmsg);
+        }
+
+        CompiledConfigParser parser = (CompiledConfigParser)pobj;
+        Serializable config = null;
+
+        try {
+            // parse it on up
+            config = parser.parseConfig(_configdef);
+        } catch (Exception e) {
+            throw new BuildException("Failure parsing config definition", e);
+        }
+
+        try {
+            // and write it on out
+            CompiledConfig.saveConfig(_target, config);
+        } catch (Exception e) {
+            throw new BuildException("Failure writing serialized config", e);
+        }
+    }
+
+    protected File _configdef;
+    protected File _target;
+    protected String _parser;
+}

src/java/com/threerings/tools/xml/CompiledConfigParser.java

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+//
+// $Id: CompiledConfigParser.java,v 1.1 2002/03/08 06:15:21 mdb Exp $
+
+package com.threerings.yohoho.tools.xml;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.Serializable;
+
+import org.xml.sax.SAXException;
+import org.apache.commons.digester.Digester;
+
+import com.threerings.yohoho.util.CompiledConfig;
+import com.threerings.yohoho.tools.CompiledConfigTask;
+
+/**
+ * An abstract base implementation of a parser that is used to compile
+ * configuration definitions into config objects for use by the client and
+ * server.
+ *
+ * @see CompiledConfig
+ * @see CompiledConfigTask
+ */
+public abstract class CompiledConfigParser
+{
+    /**
+     * Parses the supplied configuration file into a serializable
+     * configuration object.
+     */
+    public Serializable parseConfig (File source)
+        throws IOException, SAXException
+    {
+        Digester digester = new Digester();
+        digester.setDebug(99);
+        Serializable config = createConfigObject();
+        addRules(digester);
+        digester.push(config);
+        digester.parse(new FileInputStream(source));
+        return config;
+    }
+
+    /**
+     * Creates the config object instance that will be populated during
+     * the parsing process.
+     */
+    protected abstract Serializable createConfigObject ();
+
+    /**
+     * Adds the necessary digester rules for parsing the config object.
+     */
+    protected abstract void addRules (Digester digester);
+}

src/java/com/threerings/util/CompiledConfig.java

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+//
+// $Id: CompiledConfig.java,v 1.1 2002/03/08 06:15:21 mdb Exp $
+
+package com.threerings.yohoho.util;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
+/**
+ * Used to load and store compiled configuration data (generally XML files
+ * that are parsed into Java object models and then serialized for rapid
+ * and simple access on the client and server).
+ */
+public class CompiledConfig
+{
+    /**
+     * Unserializes a configuration object from the supplied input stream.
+     */
+    public static Serializable loadConfig (InputStream source)
+        throws IOException, ClassNotFoundException
+    {
+        ObjectInputStream oin = new ObjectInputStream(source);
+        return (Serializable)oin.readObject();
+    }
+
+    /**
+     * Serializes the supplied configuration object to the specified file
+     * path.
+     */
+    public static void saveConfig (File target, Serializable config)
+        throws IOException
+    {
+        FileOutputStream fout = new FileOutputStream(target);
+        ObjectOutputStream oout = new ObjectOutputStream(fout);
+        oout.writeObject(config);
+        oout.close();
+    }
+}