Add remove and removeAll functionality

Fixes odiszapc#2

Author: odiszapc

src/main/java/com/github/odiszapc/nginxparser/NgxBlock.java

@@ -21,7 +21,7 @@
 /**
  * Describes block section. Example:
  * http {
- *     ...
+ * ...
  * }
  */
 public class NgxBlock extends NgxAbstractEntry implements Iterable<NgxEntry> {
@@ -46,6 +46,38 @@ public Iterator<NgxEntry> iterator() {
         return getEntries().iterator();
     }
 
+    public void remove(NgxEntry itemToRemove) {
+        if (null == itemToRemove)
+            throw new NullPointerException("Item can not be null");
+
+        Iterator<NgxEntry> it = entries.iterator();
+        while(it.hasNext()) {
+            NgxEntry entry = it.next();
+            switch (NgxEntryType.fromClass(entry.getClass())) {
+                case PARAM:
+                    if (entry.equals(itemToRemove))
+                        it.remove();
+                    break;
+                case BLOCK:
+                    if (entry.equals(itemToRemove))
+                        it.remove();
+                    else {
+                        NgxBlock block = (NgxBlock) entry;
+                        block.remove(itemToRemove);
+                    }
+                    break;
+            }
+        }
+    }
+
+    public void removeAll(Iterable<NgxEntry> itemsToRemove) {
+        if (null == itemsToRemove)
+            throw new NullPointerException("Items can not be null");
+        for (NgxEntry itemToRemove : itemsToRemove) {
+            remove(itemToRemove);
+        }
+    }
+
     public <T extends NgxEntry> T find(Class<T> clazz, String... params) {
         List<NgxEntry> all = findAll(clazz, new ArrayList<NgxEntry>(), params);
         if (all.isEmpty())

src/test/java/com/github/odiszapc/nginxparser/AlterConfigTest.java

@@ -0,0 +1,64 @@
+package com.github.odiszapc.nginxparser;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class AlterConfigTest extends ParseTestBase {
+    @Test
+    public void removeOneLocation() throws Exception {
+        NgxConfig conf = parse("nested/c2.conf");
+        NgxEntry ngxEntry = conf.find(NgxConfig.BLOCK, "http", "server", "location");
+        conf.remove(ngxEntry);
+
+        final String expected = "" +
+                "http {\n" +
+                "  server {\n" +
+                "  }\n" +
+                "}\n";
+
+        assertEquals(new NgxDumper(conf).dump(), expected);
+    }
+
+    @Test
+    public void removeManyLocations() throws Exception {
+        NgxConfig conf = parse("nested/c4.conf");
+        List<NgxEntry> locations = conf.findAll(NgxConfig.BLOCK, "http", "server", "location");
+        assertEquals(2, locations.size());
+        conf.removeAll(locations);
+        assertEquals(0, conf.findAll(NgxConfig.BLOCK, "http", "server", "location").size());
+
+        final String expected = "" +
+                "http {\n" +
+                "  server {\n" +
+                "  }\n" +
+                "}\n";
+
+        assertEquals(new NgxDumper(conf).dump(), expected);
+    }
+
+    @Rule
+    public ExpectedException expectedEx = ExpectedException.none();
+
+    @Test
+    public void removeNullElement() throws Exception {
+        expectedEx.expect(NullPointerException.class);
+        expectedEx.expectMessage("Item can not be null");
+
+        NgxConfig conf = parse("nested/c4.conf");
+        conf.remove(null);
+    }
+
+    @Test
+    public void removeNullElements() throws Exception {
+        expectedEx.expect(NullPointerException.class);
+        expectedEx.expectMessage("Items can not be null");
+
+        NgxConfig conf = parse("nested/c4.conf");
+        conf.removeAll(null);
+    }
+}

src/test/resources/nested/c4.conf

@@ -0,0 +1,10 @@
+http {
+  server {
+    location /foo {
+      set $foo "bar";
+    }
+    location /foo {
+      set $bar "baz";
+    }
+  }
+}