Introduce AbstractStats

smack-core/src/main/java/org/jivesoftware/smack/c2s/ModularXmppClientToServerConnection.java

@@ -65,6 +65,7 @@ import org.jivesoftware.smack.fsm.StateDescriptorGraph.GraphVertex;
 import org.jivesoftware.smack.fsm.StateMachineException;
 import org.jivesoftware.smack.fsm.StateTransitionResult;
 import org.jivesoftware.smack.fsm.StateTransitionResult.AttemptResult;
+import org.jivesoftware.smack.internal.AbstractStats;
 import org.jivesoftware.smack.packet.IQ;
 import org.jivesoftware.smack.packet.Message;
 import org.jivesoftware.smack.packet.Nonza;
@@ -78,6 +79,7 @@ import org.jivesoftware.smack.parsing.SmackParsingException;
 import org.jivesoftware.smack.sasl.SASLErrorException;
 import org.jivesoftware.smack.sasl.SASLMechanism;
 import org.jivesoftware.smack.util.ArrayBlockingQueueWithShutdown;
+import org.jivesoftware.smack.util.ExtendedAppendable;
 import org.jivesoftware.smack.util.PacketParserUtils;
 import org.jivesoftware.smack.util.StringUtils;
 import org.jivesoftware.smack.xml.XmlPullParser;
@@ -1069,7 +1071,7 @@ public final class ModularXmppClientToServerConnection extends AbstractXMPPConne
         return new Stats(transportsStats, filterStats);
     }
 
-    public static final class Stats {
+    public static final class Stats extends AbstractStats {
         public final Map<Class<? extends ModularXmppClientToServerConnectionModuleDescriptor>, XmppClientToServerTransport.Stats> transportsStats;
         public final Map<String, Object> filtersStats;
 
@@ -1079,7 +1081,8 @@ public final class ModularXmppClientToServerConnection extends AbstractXMPPConne
             this.filtersStats = Collections.unmodifiableMap(filtersStats);
         }
 
-        public void appendStatsTo(Appendable appendable) throws IOException {
+        @Override
+        public void appendStatsTo(ExtendedAppendable appendable) throws IOException {
             StringUtils.appendHeading(appendable, "Connection stats", '#').append('\n');
 
             for (Map.Entry<Class<? extends ModularXmppClientToServerConnectionModuleDescriptor>, XmppClientToServerTransport.Stats> entry : transportsStats.entrySet()) {
@@ -1099,16 +1102,5 @@ public final class ModularXmppClientToServerConnection extends AbstractXMPPConne
             }
         }
 
-        @Override
-        public String toString() {
-            StringBuilder sb = new StringBuilder();
-            try {
-                appendStatsTo(sb);
-            } catch (IOException e) {
-                // Should never happen.
-                throw new AssertionError(e);
-            }
-            return sb.toString();
-        }
     }
 }

smack-core/src/main/java/org/jivesoftware/smack/internal/AbstractStats.java

@@ -0,0 +1,52 @@
+/**
+ *
+ * Copyright 2020 Florian Schmaus
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.internal;
+
+import java.io.IOException;
+
+import org.jivesoftware.smack.util.ExtendedAppendable;
+
+public abstract class AbstractStats {
+
+    public final void appendStatsTo(Appendable appendable) throws IOException {
+        appendStatsTo(new ExtendedAppendable(appendable));
+    }
+
+    public abstract void appendStatsTo(ExtendedAppendable appendable) throws IOException;
+
+    private transient String toStringCache;
+
+    @Override
+    public final String toString() {
+        if (toStringCache != null) {
+            return toStringCache;
+        }
+
+        StringBuilder sb = new StringBuilder();
+        try {
+            appendStatsTo(sb);
+        } catch (IOException e) {
+            // Should never happen.
+            throw new AssertionError(e);
+        }
+
+        toStringCache =  sb.toString();
+
+        return toStringCache;
+    }
+
+}

smack-core/src/main/java/org/jivesoftware/smack/internal/package-info.java

@@ -0,0 +1,21 @@
+/**
+ *
+ * Copyright 2020 Florian Schmaus
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Smack internal classes and interfaces.
+ */
+package org.jivesoftware.smack.internal;

smack-core/src/main/java/org/jivesoftware/smack/util/ExtendedAppendable.java

@@ -0,0 +1,56 @@
+/**
+ *
+ * Copyright 2020 Florian Schmaus.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.util;
+
+import java.io.IOException;
+
+public class ExtendedAppendable implements Appendable {
+
+    private final Appendable appendable;
+
+    public ExtendedAppendable(Appendable appendable) {
+        this.appendable = appendable;
+    }
+
+    @Override
+    public ExtendedAppendable append(CharSequence csq) throws IOException {
+        appendable.append(csq);
+        return this;
+    }
+
+    @Override
+    public ExtendedAppendable append(CharSequence csq, int start, int end) throws IOException {
+        appendable.append(csq, start, end);
+        return this;
+    }
+
+    @Override
+    public ExtendedAppendable append(char c) throws IOException {
+        appendable.append(c);
+        return this;
+    }
+
+    public ExtendedAppendable append(boolean b) throws IOException {
+        appendable.append(String.valueOf(b));
+        return this;
+    }
+
+    public ExtendedAppendable append(int i) throws IOException {
+        appendable.append(String.valueOf(i));
+        return this;
+    }
+}