Add 'src/be/nikiroo/utils/' from commit '46add0670fdee4bd936a13fe2448c5e20a7ffd0a'

[fanfix.git] / src / be / nikiroo / utils / TraceHandler.java

diff --git a/src/be/nikiroo/utils/TraceHandler.java b/src/be/nikiroo/utils/TraceHandler.java
new file mode 100644 (file)
index 0000000..0a09712
--- /dev/null
+++ b/src/be/nikiroo/utils/TraceHandler.java
@@ -0,0 +1,156 @@
+package be.nikiroo.utils;
+
+/**
+ * A handler when a trace message is sent or when a recoverable exception was
+ * caught by the program.
+ * 
+ * @author niki
+ */
+public class TraceHandler {
+       private final boolean showErrors;
+       private final boolean showErrorDetails;
+       private final int traceLevel;
+       private final int maxPrintSize;
+
+       /**
+        * Create a default {@link TraceHandler} that will print errors on stderr
+        * (without details) and no traces.
+        */
+       public TraceHandler() {
+               this(true, false, false);
+       }
+
+       /**
+        * Create a default {@link TraceHandler}.
+        * 
+        * @param showErrors
+        *            show errors on stderr
+        * @param showErrorDetails
+        *            show more details when printing errors
+        * @param showTraces
+        *            show level 1 traces on stderr, or no traces at all
+        */
+       public TraceHandler(boolean showErrors, boolean showErrorDetails,
+                       boolean showTraces) {
+               this(showErrors, showErrorDetails, showTraces ? 1 : 0);
+       }
+
+       /**
+        * Create a default {@link TraceHandler}.
+        * 
+        * @param showErrors
+        *            show errors on stderr
+        * @param showErrorDetails
+        *            show more details when printing errors
+        * @param traceLevel
+        *            show traces of this level or lower (0 means "no traces",
+        *            higher means more traces)
+        */
+       public TraceHandler(boolean showErrors, boolean showErrorDetails,
+                       int traceLevel) {
+               this(showErrors, showErrorDetails, traceLevel, -1);
+       }
+
+       /**
+        * Create a default {@link TraceHandler}.
+        * 
+        * @param showErrors
+        *            show errors on stderr
+        * @param showErrorDetails
+        *            show more details when printing errors
+        * @param traceLevel
+        *            show traces of this level or lower (0 means "no traces",
+        *            higher means more traces)
+        * @param maxPrintSize
+        *            the maximum size at which to truncate traces data (or -1 for
+        *            "no limit")
+        */
+       public TraceHandler(boolean showErrors, boolean showErrorDetails,
+                       int traceLevel, int maxPrintSize) {
+               this.showErrors = showErrors;
+               this.showErrorDetails = showErrorDetails;
+               this.traceLevel = Math.max(traceLevel, 0);
+               this.maxPrintSize = maxPrintSize;
+       }
+
+       /**
+        * The trace level of this {@link TraceHandler}.
+        * 
+        * @return the level
+        */
+       public int getTraceLevel() {
+               return traceLevel;
+       }
+
+       /**
+        * An exception happened, log it.
+        * 
+        * @param e
+        *            the exception
+        */
+       public void error(Exception e) {
+               if (showErrors) {
+                       if (showErrorDetails) {
+                               long now = System.currentTimeMillis();
+                               System.err.print(StringUtils.fromTime(now) + ": ");
+                               e.printStackTrace();
+                       } else {
+                               error(e.toString());
+                       }
+               }
+       }
+
+       /**
+        * An error happened, log it.
+        * 
+        * @param message
+        *            the error message
+        */
+       public void error(String message) {
+               if (showErrors) {
+                       long now = System.currentTimeMillis();
+                       System.err.println(StringUtils.fromTime(now) + ": " + message);
+               }
+       }
+
+       /**
+        * A trace happened, show it.
+        * <p>
+        * By default, will only be effective if {@link TraceHandler#traceLevel} is
+        * not 0.
+        * <p>
+        * A call to this method is equivalent to a call to
+        * {@link TraceHandler#trace(String, int)} with a level of 1.
+        * 
+        * @param message
+        *            the trace message
+        */
+       public void trace(String message) {
+               trace(message, 1);
+       }
+
+       /**
+        * A trace happened, show it.
+        * <p>
+        * By default, will only be effective if {@link TraceHandler#traceLevel} is
+        * not 0 and the level is lower or equal to it.
+        * 
+        * @param message
+        *            the trace message
+        * @param level
+        *            the trace level
+        */
+       public void trace(String message, int level) {
+               if (traceLevel > 0 && level <= traceLevel) {
+                       long now = System.currentTimeMillis();
+                       System.err.print(StringUtils.fromTime(now) + ": ");
+                       if (maxPrintSize > 0 && message.length() > maxPrintSize) {
+
+                               System.err
+                                               .println(message.substring(0, maxPrintSize) + "[...]");
+                       } else {
+                               System.err.println(message);
+                       }
+               }
+       }
+}