Added command context and the ability to query arguments from it

src/main/java/net/minecraft/commands/arguments/IntegerArgumentType.java

@@ -1,6 +1,7 @@
 package net.minecraft.commands.arguments;
 
 import com.google.common.base.Splitter;
+import net.minecraft.commands.context.CommandContext;
 import net.minecraft.commands.exceptions.ArgumentValidationException;
 import net.minecraft.commands.exceptions.IllegalArgumentSyntaxException;
 
@@ -27,6 +28,10 @@ public class IntegerArgumentType implements CommandArgumentType<Integer> {
         return new IntegerArgumentType(min, max);
     }
 
+    public static int getInteger(CommandContext context, String name) {
+        return context.getArgument(name, int.class).getResult();
+    }
+
     @Override
     public CommandArgumentParseResult<Integer> parse(String command) throws IllegalArgumentSyntaxException, ArgumentValidationException {
         String raw = SPLITTER.split(command).iterator().next();

src/main/java/net/minecraft/commands/context/CommandContext.java

@@ -0,0 +1,29 @@
+package net.minecraft.commands.context;
+
+import com.google.common.primitives.Primitives;
+import net.minecraft.commands.arguments.CommandArgumentType;
+
+import java.util.Map;
+
+public class CommandContext {
+    private final Map<String, CommandArgumentType.CommandArgumentParseResult<?>> arguments;
+
+    public CommandContext(Map<String, CommandArgumentType.CommandArgumentParseResult<?>> arguments) {
+        this.arguments = arguments;
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> CommandArgumentType.CommandArgumentParseResult<T> getArgument(String name, Class<T> clazz) {
+        CommandArgumentType.CommandArgumentParseResult<?> argument = arguments.get(name);
+
+        if (argument == null) {
+            throw new IllegalArgumentException("No such argument '" + name + "' exists on this command");
+        }
+
+        if (Primitives.wrap(clazz).isAssignableFrom(argument.getResult().getClass())) {
+            return (CommandArgumentType.CommandArgumentParseResult<T>) argument;
+        } else {
+            throw new IllegalArgumentException("Argument '" + name + "' is defined as " + argument.getResult().getClass().getSimpleName() + ", not " + clazz);
+        }
+    }
+}

src/main/java/net/minecraft/commands/context/CommandContextBuilder.java

@@ -0,0 +1,22 @@
+package net.minecraft.commands.context;
+
+import com.google.common.collect.Maps;
+import net.minecraft.commands.arguments.CommandArgumentType;
+
+import java.util.Map;
+
+public class CommandContextBuilder {
+    private final Map<String, CommandArgumentType.CommandArgumentParseResult<?>> arguments = Maps.newHashMap();
+
+    public CommandContextBuilder() {
+    }
+
+    public CommandContextBuilder withArgument(String name, CommandArgumentType.CommandArgumentParseResult<?> argument) {
+        this.arguments.put(name, argument);
+        return this;
+    }
+
+    public CommandContext build() {
+        return new CommandContext(arguments);
+    }
+}

src/main/java/net/minecraft/commands/context/package-info.java

@@ -0,0 +1,4 @@
+@ParametersAreNonnullByDefault
+package net.minecraft.commands.context;
+
+import javax.annotation.ParametersAreNonnullByDefault;

src/main/test/net/minecraft/commands/arguments/IntegerArgumentTypeTest.java

@@ -1,5 +1,7 @@
 package net.minecraft.commands.arguments;
 
+import net.minecraft.commands.context.CommandContext;
+import net.minecraft.commands.context.CommandContextBuilder;
 import net.minecraft.commands.exceptions.ArgumentValidationException;
 import net.minecraft.commands.exceptions.IllegalArgumentSyntaxException;
 import org.junit.Before;
@@ -55,4 +57,11 @@ public class IntegerArgumentTypeTest {
         assertThat(result.getRaw(), is("100"));
         assertThat(result.getResult(), is(100));
     }
+
+    @Test
+    public void testGetInteger() throws Exception {
+        CommandContext context = new CommandContextBuilder().withArgument("foo", type.parse("100")).build();
+
+        assertThat(IntegerArgumentType.getInteger(context, "foo"), is(100));
+    }
 }

src/main/test/net/minecraft/commands/context/CommandContextTest.java

@@ -0,0 +1,34 @@
+package net.minecraft.commands.context;
+
+import net.minecraft.commands.arguments.IntegerArgumentType;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+public class CommandContextTest {
+    CommandContext context;
+
+    @Before
+    public void setUp() throws Exception {
+        context = new CommandContextBuilder().build();
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetArgument_nonexistent() throws Exception {
+        context.getArgument("foo", Object.class);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetArgument_wrongType() throws Exception {
+        context = new CommandContextBuilder().withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
+        context.getArgument("foo", String.class);
+    }
+
+    @Test
+    public void testGetArgument() throws Exception {
+        context = new CommandContextBuilder().withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
+        assertThat(context.getArgument("foo", int.class).getResult(), is(123));
+    }
+}