Add parser for annotations

src/de/inetsoftware/classparser/Annotations.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2017 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.classparser;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Volker Berlin
+ */
+public class Annotations {
+
+    private final Map<String,Map<String,Object>> annotations = new HashMap<>();
+
+    /**
+     * Read the annotations structure.
+     * http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.7.17
+     * @param input
+     * @param constantPool
+     * @throws IOException
+     */
+    public Annotations( DataInputStream input, ConstantPool constantPool ) throws IOException {
+        int count = input.readUnsignedShort();
+        for( int i = 0; i < count; i++ ) {
+            String className = (String)constantPool.get( input.readUnsignedShort() );
+            className = className.substring( 1, className.length() - 1 ).replace( '/', '.' ); // has the form: "Lcom/package/ClassName;"
+            Map<String,Object> valuePairs = new HashMap<>();
+            annotations.put( className, valuePairs );
+
+            int valuePairCount = input.readUnsignedShort();
+            for( int p = 0; p < valuePairCount; p++ ) {
+                String key = (String)constantPool.get( input.readUnsignedShort() );
+                int type = input.readUnsignedByte();
+                Object value;
+                switch( type ) {
+                    case 'B':
+                    case 'C':
+                    case 'D':
+                    case 'F':
+                    case 'I':
+                    case 'J':
+                    case 'S':
+                    case 'Z':
+                    case 's':
+                        value = constantPool.get( input.readUnsignedShort() );
+                        break;
+                    default:
+                        // TODO other possible values for type: e c @ [
+                        throw new IOException( "Unknown annotation value type pool type: " + type );
+                }
+                valuePairs.put( key, value );
+            }
+        }
+    }
+
+    /**
+     * Get the key values of the annotation for the given class.
+     * @param className the class name of the annotation
+     * @return a map with the properties of the annotation or null if there is no annotation.
+     */
+    public Map<String, Object> get( String className ) {
+        return annotations.get( className );
+    }
+}

src/de/inetsoftware/classparser/MethodInfo.java

@@ -18,6 +18,8 @@ package de.inetsoftware.classparser;
 
 import java.io.DataInputStream;
 import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 
 import de.inetsoftware.classparser.Attributes.AttributeInfo;
 
@@ -135,4 +137,16 @@ public class MethodInfo {
         }
         return exceptions;
     }
+
+    /**
+     * Get the annotations with @Retention(RetentionPolicy.CLASS)
+     * @return the annotations if there any exists else null
+     */
+    public Annotations getRuntimeInvisibleAnnotations() throws IOException {
+        AttributeInfo data = attributes.get( "RuntimeInvisibleAnnotations" );
+        if( data != null ) {
+            return new Annotations( data.getDataInputStream(), constantPool );
+        }
+        return null;
+    }
 }