Initial commit of chained logging framework for samples/common
Change-Id: I88af0d1bae64624ad7d5afece9f6c21772841e30
diff --git a/common/logger/LogWrapper.java b/common/logger/LogWrapper.java
new file mode 100644
index 0000000..16a9e7b
--- /dev/null
+++ b/common/logger/LogWrapper.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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 com.example.android.common.logger;
+
+import android.util.Log;
+
+/**
+ * Helper class which wraps Android's native Log utility in the Logger interface. This way
+ * normal DDMS output can be one of the many targets receiving and outputting logs simultaneously.
+ */
+public class LogWrapper implements LogNode {
+
+ // For piping: The next node to receive Log data after this one has done its work.
+ private LogNode mNext;
+
+ /**
+ * Returns the next LogNode in the linked list.
+ */
+ public LogNode getNext() {
+ return mNext;
+ }
+
+ /**
+ * Sets the LogNode data will be sent to..
+ */
+ public void setNext(LogNode node) {
+ mNext = node;
+ }
+
+ /**
+ * Prints data out to the console using Android's native log mechanism.
+ * @param priority Log level of the data being logged. Verbose, Error, etc.
+ * @param tag Tag for for the log data. Can be used to organize log statements.
+ * @param msg The actual message to be logged. The actual message to be logged.
+ * @param tr If an exception was thrown, this can be sent along for the logging facilities
+ * to extract and print useful information.
+ */
+ @Override
+ public void println(int priority, String tag, String msg, Throwable tr) {
+ // There actually are log methods that don't take a msg parameter. For now,
+ // if that's the case, just convert null to the empty string and move on.
+ String useMsg = msg;
+ if (useMsg == null) {
+ useMsg = "";
+ }
+
+ // If an exeption was provided, convert that exception to a usable string and attach
+ // it to the end of the msg method.
+ if (tr != null) {
+ msg += "\n" + Log.getStackTraceString(tr);
+ }
+
+ // This is functionally identical to Log.x(tag, useMsg);
+ // For instance, if priority were Log.VERBOSE, this would be the same as Log.v(tag, useMsg)
+ Log.println(priority, tag, useMsg);
+
+ // If this isn't the last node in the chain, move things along.
+ if (mNext != null) {
+ mNext.println(priority, tag, msg, tr);
+ }
+ }
+}