FlatLogListener that uses RemoveNewLinesMapper to remove newlines and…

… optional combine spaces in LogEvents.

This differs from using RemoveNewLinesMapper in the MappingLogEventWriter in that it modifies the LogEvent returning a FrozenLogEvent instead of modifying the data just before writing to the output.

This listener thus doesn't write to output, but similarly to the ProtectionLogListener, modifies the LogEvent that is processed by subsequent LogListeners defined in the LoggerAdapter.

jpos/src/main/java/org/jpos/util/FlatLogListener.java

@@ -0,0 +1,66 @@
+/*
+ * jPOS Project [http://jpos.org]
+ * Copyright (C) 2000-2020 jPOS Software SRL
+ *
+ * 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.util;
+
+import org.jpos.core.Configurable;
+import org.jpos.core.Configuration;
+import org.jpos.core.ConfigurationException;
+import org.jpos.util.function.RemoveNewLinesMapper;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+/**
+ * A LogListener that uses the RemoveNewLinesMapper to remove newlines from the LogEvent dump output.
+ *
+ * This LogListener will modify the LogEvents for all subsequent LogListeners in the configuration.
+ * If this is not what you want, order your LogListeners to minimize the effect.
+ *
+ * @see RemoveNewLinesMapper RemoveNewLinesMapper for more details.
+ * @author Alejandro P. Revilla
+ * @author Alwyn Schoeman
+ * @since 2.1.4
+ */
+public class FlatLogListener implements LogListener, Configurable, Destroyable {
+    RemoveNewLinesMapper mapper = new RemoveNewLinesMapper();
+    ByteArrayOutputStream captureStream = new ByteArrayOutputStream();
+    PrintStream p = new PrintStream(captureStream);
+
+    @Override
+    public void setConfiguration(Configuration cfg) throws ConfigurationException {
+        mapper.setConfiguration(cfg);
+    }
+
+    @Override
+    public synchronized LogEvent log(LogEvent ev) {
+        ev.dump(p, "");
+        byte[] result = mapper.apply(captureStream.toByteArray());
+        captureStream.reset();
+        return new FrozenLogEvent(new String(result));
+    }
+
+    @Override
+    public void destroy() {
+        if (p != null) {
+            p.close();
+            p = null;
+            captureStream = null;
+        }
+    }
+}

jpos/src/main/java/org/jpos/util/FrozenLogEvent.java

@@ -23,6 +23,10 @@
 
 public class FrozenLogEvent extends LogEvent implements Serializable {
     private String frozen;
+
+    public FrozenLogEvent(String frozen) {
+        this.frozen = frozen;
+    }
     public FrozenLogEvent (LogEvent evt) {
         super(evt.getSource(), evt.getTag(), evt.getRealm());
         frozen = evt.toString();