protected void buildHashCode()

in drools-mvel/src/main/java/org/drools/mvel/asm/DefaultBeanClassBuilder.java [1595:1740]
123 lines of code
11 McCabe index (conditional complexity)

    protected void buildHashCode(ClassVisitor cw,
                                 ClassDefinition classDef) {

        MethodVisitor mv;
        // Building hashCode() method
        {
            mv = cw.visitMethod( Opcodes.ACC_PUBLIC,
                                 "hashCode",
                                 "()I",
                                 null,
                                 null );
            mv.visitCode();
            Label l0 = null;
            if ( this.debug ) {
                l0 = new Label();
                mv.visitLabel( l0 );
            }

            // int result = 1;
            mv.visitInsn( Opcodes.ICONST_1 );
            mv.visitVarInsn( Opcodes.ISTORE,
                             1 );

            // for each key field
            for ( FieldDefinition field : classDef.getFieldsDefinitions() ) {
                if ( field.isKey() ) {

                    // result = result * 31 + <attr_hash>
                    mv.visitVarInsn( Opcodes.ILOAD,
                                     1 );
                    mv.visitIntInsn( Opcodes.BIPUSH,
                                     31 );
                    mv.visitVarInsn( Opcodes.ILOAD,
                                     1 );
                    mv.visitInsn( Opcodes.IMUL );

                    mv.visitVarInsn(Opcodes.ALOAD,
                                    0);

                    visitFieldOrGetter(mv, classDef, field);

                    if ( "boolean".equals( field.getTypeName() ) ) {
                        // attr_hash ::== <boolean_attr> ? 1231 : 1237;
                        Label blabel1 = new Label();
                        mv.visitJumpInsn( Opcodes.IFEQ,
                                          blabel1 );
                        mv.visitIntInsn( Opcodes.SIPUSH,
                                         1231 );
                        Label blabel2 = new Label();
                        mv.visitJumpInsn( Opcodes.GOTO,
                                          blabel2 );
                        mv.visitLabel( blabel1 );
                        mv.visitIntInsn( Opcodes.SIPUSH,
                                         1237 );
                        mv.visitLabel( blabel2 );
                    } else if ( "long".equals( field.getTypeName() ) ) {
                        // attr_hash ::== (int) (longAttr ^ (longAttr >>> 32))
                        mv.visitVarInsn( Opcodes.ALOAD,
                                         0 );

                        visitFieldOrGetter(mv, classDef, field);

                        mv.visitIntInsn( Opcodes.BIPUSH,
                                         32 );
                        mv.visitInsn( Opcodes.LUSHR );
                        mv.visitInsn( Opcodes.LXOR );
                        mv.visitInsn( Opcodes.L2I );

                    } else if ( "float".equals( field.getTypeName() ) ) {
                        // attr_hash ::== Float.floatToIntBits( floatAttr );
                        mv.visitMethodInsn( Opcodes.INVOKESTATIC,
                                            Type.getInternalName( Float.class ),
                                            "floatToIntBits",
                                            "(F)I" );
                    } else if ( "double".equals( field.getTypeName() ) ) {
                        // attr_hash ::== (int) (Double.doubleToLongBits( doubleAttr ) ^ (Double.doubleToLongBits( doubleAttr ) >>> 32));
                        mv.visitMethodInsn( Opcodes.INVOKESTATIC,
                                            Type.getInternalName( Double.class ),
                                            "doubleToLongBits",
                                            "(D)J" );
                        mv.visitInsn( Opcodes.DUP2 );
                        mv.visitIntInsn( Opcodes.BIPUSH,
                                         32 );
                        mv.visitInsn( Opcodes.LUSHR );
                        mv.visitInsn( Opcodes.LXOR );
                        mv.visitInsn( Opcodes.L2I );
                    } else if ( !BuildUtils.isPrimitive(field.getTypeName()) ) {
                        // attr_hash ::== ((objAttr == null) ? 0 : objAttr.hashCode());
                        Label olabel1 = new Label();
                        mv.visitJumpInsn( Opcodes.IFNONNULL,
                                          olabel1 );
                        mv.visitInsn( Opcodes.ICONST_0 );
                        Label olabel2 = new Label();
                        mv.visitJumpInsn( Opcodes.GOTO,
                                          olabel2 );
                        mv.visitLabel( olabel1 );
                        mv.visitVarInsn( Opcodes.ALOAD,
                                         0 );

                        visitFieldOrGetter(mv, classDef, field);

                        if ( ! BuildUtils.isArray( field.getTypeName() ) ) {
                            mv.visitMethodInsn( Opcodes.INVOKEVIRTUAL,
                                                "java/lang/Object",
                                                "hashCode",
                                                "()I" );
                        } else {
                            mv.visitMethodInsn( INVOKESTATIC,
                                                "java/util/Arrays",
                                                "hashCode",
                                                "(" + BuildUtils.arrayType( field.getTypeName() ) + ")I");
                        }
                        mv.visitLabel( olabel2 );
                    }

                    mv.visitInsn( Opcodes.IADD );
                    mv.visitVarInsn( Opcodes.ISTORE,
                                     1 );
                }
            }
            mv.visitVarInsn( Opcodes.ILOAD,
                             1 );
            mv.visitInsn( Opcodes.IRETURN );

            Label lastLabel;
            if ( this.debug ) {
                lastLabel = new Label();
                mv.visitLabel( lastLabel );
                mv.visitLocalVariable( "this",
                                       BuildUtils.getTypeDescriptor( classDef.getClassName() ),
                                       null,
                                       l0,
                                       lastLabel,
                                       0 );
                mv.visitLocalVariable( "hash",
                                       Type.getDescriptor( int.class ),
                                       null,
                                       l0,
                                       lastLabel,
                                       1 );
            }
            mv.visitMaxs( 0,
                          0 );
            mv.visitEnd();
        }
    }