added experimental Groovy participant

modules/groovy/src/main/java/org/jpos/transaction/participant/GroovyParticipant.java

@@ -0,0 +1,174 @@
+/*
+ * jPOS Project [http://jpos.org]
+ * Copyright (C) 2000-2016 Alejandro P. Revilla
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.jpos.transaction.participant;
+
+import groovy.lang.Binding;
+import groovy.lang.GroovyShell;
+import org.jdom2.Element;
+import org.jpos.core.Configurable;
+import org.jpos.core.Configuration;
+import org.jpos.core.ConfigurationException;
+import org.jpos.core.XmlConfigurable;
+import org.jpos.transaction.AbortParticipant;
+import org.jpos.transaction.Context;
+import org.jpos.transaction.TransactionManager;
+import org.jpos.transaction.TransactionParticipant;
+import org.jpos.util.Log;
+import java.io.File;
+import java.io.IOException;
+import java.io.Serializable;
+
+/**
+ * A TransactionParticipant whose prepare, commit and abort methods can be
+ * specified using Groovy scripts. <BR>
+ * To indicate what code to execute for any of the TM life-cycle methods just add
+ * an element named 'prepare', 'commit' or 'abort' and optionally 'prepare-for-abort'
+ * contained in that of the participant. <BR>
+ *
+ * The 'prepare' and 'prepare-for-abort' methods are expected to return an Integer object
+ * with the TM standard result values (PREPARE, ABORT and its modifiers).
+ *
+ * The Groovy script code can be placed as part of the element's content or in an
+ * external file pointed by the 'src' attribute.
+ *
+ * Usage:
+ *
+ * <pre>
+ *     Add a transaction participant like this:
+ *     &lt;participant class="org.jpos.transaction.participant.GroovyParticipant" logger="Q2" realm="groovy-test"/&gt;
+ *
+ *     &lt;prepare src="deploy/prepare.groovy" /&gt;
+ *     &lt;commit src="deploy/commit.groovy" /&gt;
+ *     &lt;abort src="deploy/abort.groovy" /&gt;
+ * </pre>
+ */
+
+@SuppressWarnings("unused")
+public class GroovyParticipant extends Log
+    implements TransactionParticipant, AbortParticipant, XmlConfigurable, Configurable
+{
+    private Object prepare;
+    private Object prepareForAbort;
+    private Object commit;
+    private Object abort;
+    private TransactionManager tm;
+    private Configuration cfg;
+    private final String groovyShellKey  = ".groovy-" + Integer.toString(hashCode());
+
+    public int prepare (long id, Serializable ctx) {
+        try {
+            return (int) eval(getShell(id, ctx), prepare);
+        } catch (Exception e) {
+            error(e);
+        }
+        return ABORTED;
+    }
+    public int prepareForAbort (long id, Serializable ctx) {
+        if (prepareForAbort == null) {
+            return PREPARED | NO_JOIN | READONLY; // nothing to do
+        }
+        try {
+            return (int) eval(getShell(id, ctx), prepareForAbort);
+        } catch (Exception e) {
+            error(e);
+        }
+        return ABORTED;
+    }
+    public void commit(long id, Serializable ctx) {
+        if (commit != null) {
+            try {
+                eval(getShell(id, ctx), commit);
+            } catch (Exception e) {
+                error(e);
+            }
+        }
+    }
+    public void abort(long id, Serializable ctx) {
+        if (commit != null) {
+            try {
+                eval(getShell(id, ctx), abort);
+            } catch (Exception e) {
+                error(e);
+            }
+        }
+    }
+
+    public void setTransactionManager (TransactionManager tm) {
+        this.tm = tm;
+    }
+
+    @Override
+    public void setConfiguration(Configuration cfg) throws ConfigurationException {
+        this.cfg = cfg;
+    }
+    @Override
+    public void setConfiguration(Element e) throws ConfigurationException {
+        prepare = getScript(e.getChild("prepare"));
+        prepareForAbort = getScript(e.getChild("prepare-for-abort"));
+        commit = getScript(e.getChild("commit"));
+        abort = getScript(e.getChild("abort"));
+    }
+
+    private Object getScript (Element e) throws ConfigurationException {
+        if (e != null) {
+            String src = e.getAttributeValue("src");
+            if (src != null) {
+                File f = new File(src);
+                if (f.canRead())
+                    throw new ConfigurationException ("Can't ready '" + src + "'");
+                return f;
+            }
+            return e.getText();
+        }
+        return null;
+    }
+
+    private Object eval (GroovyShell shell, Object script) throws IOException {
+        if (script instanceof File)
+            return shell.evaluate((File)script);
+        else if (script instanceof String)
+            return shell.evaluate((String)script);
+        return null;
+    }
+
+    private GroovyShell getShell (long id, Serializable context) {
+        GroovyShell shell;
+        if (context instanceof Context) {
+            Context ctx = (Context) context;
+            shell = (GroovyShell) ctx.get(groovyShellKey);
+            if (shell == null) {
+                shell = new GroovyShell(newBinding(id, ctx));
+                ctx.put (groovyShellKey, shell);
+            }
+        } else {
+            shell = new GroovyShell(newBinding(id, context));
+        }
+        return shell;
+    }
+
+    private Binding newBinding (long id, Serializable ctx) {
+        Binding binding = new Binding();
+        binding.setVariable("id", id);
+        binding.setVariable("ctx", ctx);
+        binding.setVariable("log", this);
+        binding.setVariable("tm", tm);
+        binding.setVariable("cfg", cfg);
+        return binding;
+    }
+}