The command catalog supports enumerating commands registered through
a services list, converting each entry into a CommandRef and making
that available to callers on demand. The CommandRef can be later used
to create a command instance or just to obtain documentation about it.
All current commands are listed in the service registration.
Signed-off-by: Shawn O. Pearce <spearce@xxxxxxxxxxx>
---
.../services/org.spearce.jgit.pgm.TextBuiltin | 12 ++
.../src/org/spearce/jgit/pgm/CommandCatalog.java | 188 ++++++++++++++++++++
2 files changed, 200 insertions(+), 0 deletions(-)
create mode 100644 org.spearce.jgit.pgm/src/META-INF/services/org.spearce.jgit.pgm.TextBuiltin
create mode 100644 org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/CommandCatalog.java
diff --git a/org.spearce.jgit.pgm/src/META-INF/services/org.spearce.jgit.pgm.TextBuiltin b/org.spearce.jgit.pgm/src/META-INF/services/org.spearce.jgit.pgm.TextBuiltin
new file mode 100644
index 0000000..69ef046
--- /dev/null
+++ b/org.spearce.jgit.pgm/src/META-INF/services/org.spearce.jgit.pgm.TextBuiltin
@@ -0,0 +1,12 @@
+org.spearce.jgit.pgm.DiffTree
+org.spearce.jgit.pgm.Fetch
+org.spearce.jgit.pgm.Glog
+org.spearce.jgit.pgm.IndexPack
+org.spearce.jgit.pgm.Log
+org.spearce.jgit.pgm.LsRemote
+org.spearce.jgit.pgm.LsTree
+org.spearce.jgit.pgm.MergeBase
+org.spearce.jgit.pgm.Push
+org.spearce.jgit.pgm.RevList
+org.spearce.jgit.pgm.ShowRev
+org.spearce.jgit.pgm.Tag
diff --git a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/CommandCatalog.java b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/CommandCatalog.java
new file mode 100644
index 0000000..13c585c
--- /dev/null
+++ b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/CommandCatalog.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2008, Shawn O. Pearce <spearce@xxxxxxxxxxx>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ *
+ * - Neither the name of the Git Development Community nor the
+ * names of its contributors may be used to endorse or promote
+ * products derived from this software without specific prior
+ * written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.spearce.jgit.pgm;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Vector;
+
+/**
+ * List of all commands known by jgit's command line tools.
+ * <p>
+ * Commands are implementations of {@link TextBuiltin}, with an optional
+ * {@link Command} class annotation to insert additional documentation or
+ * override the default command name (which is guessed from the class name).
+ * <p>
+ * Commands may be registered by adding them to a services file in the same JAR
+ * (or classes directory) as the command implementation. The service file name
+ * is <code>META-INF/services/org.spearce.jgit.pgm.TextBuiltin</code> and it
+ * contains one concrete implementation class name per line.
+ * <p>
+ * Command registration is identical to Java 6's services, however the catalog
+ * uses a lightweight wrapper to delay creating a command instance as much as
+ * possible. This avoids initializing the AWT or SWT GUI toolkits even if the
+ * command's constructor might require them.
+ */
+public class CommandCatalog {
+ private static final CommandCatalog INSTANCE = new CommandCatalog();
+
+ /**
+ * Locate a single command by its user friendly name.
+ *
+ * @param name
+ * name of the command. Typically in dash-lower-case-form, which
+ * was derived from the DashLowerCaseForm class name.
+ * @return the command instance; null if no command exists by that name.
+ */
+ public static CommandRef get(final String name) {
+ return INSTANCE.commands.get(name);
+ }
+
+ /**
+ * @return all known commands, sorted by command name.
+ */
+ public static CommandRef[] all() {
+ return toSortedArray(INSTANCE.commands.values());
+ }
+
+ /**
+ * @return all common commands, sorted by command name.
+ */
+ public static CommandRef[] common() {
+ final ArrayList<CommandRef> common = new ArrayList<CommandRef>();
+ for (final CommandRef c : INSTANCE.commands.values())
+ if (c.isCommon())
+ common.add(c);
+ return toSortedArray(common);
+ }
+
+ private static CommandRef[] toSortedArray(final Collection<CommandRef> c) {
+ final CommandRef[] r = c.toArray(new CommandRef[c.size()]);
+ Arrays.sort(r, new Comparator<CommandRef>() {
+ public int compare(final CommandRef o1, final CommandRef o2) {
+ return o1.getName().compareTo(o2.getName());
+ }
+ });
+ return r;
+ }
+
+ private final ClassLoader ldr;
+
+ private final Map<String, CommandRef> commands;
+
+ private CommandCatalog() {
+ ldr = Thread.currentThread().getContextClassLoader();
+ commands = new HashMap<String, CommandRef>();
+
+ final Enumeration<URL> catalogs = catalogs();
+ while (catalogs.hasMoreElements())
+ scan(catalogs.nextElement());
+ }
+
+ private Enumeration<URL> catalogs() {
+ try {
+ final String pfx = "META-INF/services/";
+ return ldr.getResources(pfx + TextBuiltin.class.getName());
+ } catch (IOException err) {
+ return new Vector<URL>().elements();
+ }
+ }
+
+ private void scan(final URL cUrl) {
+ final BufferedReader cIn;
+ try {
+ final InputStream in = cUrl.openStream();
+ cIn = new BufferedReader(new InputStreamReader(in, "UTF-8"));
+ } catch (IOException err) {
+ // If we cannot read from the service list, go to the next.
+ //
+ return;
+ }
+
+ try {
+ String line;
+ while ((line = cIn.readLine()) != null) {
+ if (line.length() > 0 && !line.startsWith("#"))
+ load(line);
+ }
+ } catch (IOException err) {
+ // If we failed during a read, ignore the error.
+ //
+ } finally {
+ try {
+ cIn.close();
+ } catch (IOException e) {
+ // Ignore the close error; we are only reading.
+ }
+ }
+ }
+
+ private void load(final String cn) {
+ final Class<? extends TextBuiltin> clazz;
+ try {
+ clazz = Class.forName(cn, false, ldr).asSubclass(TextBuiltin.class);
+ } catch (ClassNotFoundException notBuiltin) {
+ // Doesn't exist, even though the service entry is present.
+ //
+ return;
+ } catch (ClassCastException notBuiltin) {
+ // Isn't really a builtin, even though its listed as such.
+ //
+ return;
+ }
+
+ final CommandRef cr;
+ final Command a = clazz.getAnnotation(Command.class);
+ if (a != null)
+ cr = new CommandRef(clazz, a);
+ else
+ cr = new CommandRef(clazz);
+
+ commands.put(cr.getName(), cr);
+ }
+}
--
1.6.0.rc0.182.gb96c7
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