Summary

Document that the syntax part of the syntaxAndPattern parameter of java.nio.file.FileSystem.getPathMatcher(String) must not be empty.

Problem

The current specification states:

The syntaxAndPattern parameter identifies the syntax and the pattern and takes the form:

 syntax:pattern

where ':' stands for itself.

which does not make it explicit that syntax must not be empty.

Solution

Change the description of the parameter to

The syntaxAndPattern parameter identifies the syntax and the pattern and takes the form:

 syntax:pattern

where syntax must not be empty and ':' stands for itself.

Specification

@@ -304,7 +304,8 @@ public abstract class FileSystem
      * <blockquote><pre>
      * <i>syntax</i><b>:</b><i>pattern</i>
      * </pre></blockquote>
-     * where {@code ':'} stands for itself.
+     * where <i>syntax</i> is the non-empty name of the syntax, <i>pattern</i>
+     * is a possibly-empty pattern string, and {@code ':'} stands for itself.
      *
      * <p> A {@code FileSystem} implementation supports the "{@code glob}" and
      * "{@code regex}" syntaxes, and may support others. The value of the syntax