org.jsimpledb.JReferenceField Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jsimpledb-main Show documentation
JSimpleDB classes that map Java model classes onto the core API.
There is a newer version: 3.6.1

/*
 * Copyright (C) 2015 Archie L. Cobbs. All rights reserved.
 */

package org.jsimpledb;

import com.google.common.base.Converter;
import com.google.common.reflect.TypeToken;

import java.lang.reflect.Method;
import java.util.TreeSet;

import org.jsimpledb.core.DeleteAction;
import org.jsimpledb.core.ObjId;
import org.jsimpledb.core.ReferenceFieldType;
import org.jsimpledb.schema.ReferenceSchemaField;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

/**
 * Represents a reference field in a {@link JClass} or a reference sub-field of a complex field in a {@link JClass}.
 */
public class JReferenceField extends JSimpleField {

    final DeleteAction onDelete;
    final boolean cascadeDelete;

    JReferenceField(JSimpleDB jdb, String name, int storageId, String description, TypeToken typeToken,
      org.jsimpledb.annotation.JField annotation, Method getter, Method setter) {
        super(jdb, name, storageId, typeToken, new ReferenceFieldType(), true, annotation, description, getter, setter);
        this.onDelete = annotation.onDelete();
        this.cascadeDelete = annotation.cascadeDelete();
    }

    @Override
    public JObject getValue(JObject jobj) {
        return (JObject)super.getValue(jobj);
    }

    @Override
    public  R visit(JFieldSwitch target) {
        return target.caseJReferenceField(this);
    }

    @Override
    public Converter getConverter(JTransaction jtx) {
        return new ReferenceConverter(jtx, JObject.class).reverse();
    }

    /**
     * Get the {@link DeleteAction} configured for this field.
     *
     * @return this field's {@link DeleteAction}
     */
    public DeleteAction getOnDelete() {
        return this.onDelete;
    }

    /**
     * Determine whether the referred-to object should be deleted when an object containing this field is deleted.
     *
     * @return this field's delete cascade setting
     */
    public boolean isCascadeDelete() {
        return this.cascadeDelete;
    }

    @Override
    boolean isSameAs(JField that0) {
        if (!super.isSameAs(that0))
            return false;
        final JReferenceField that = (JReferenceField)that0;
        if (!this.onDelete.equals(that.onDelete))
            return false;
        if (this.cascadeDelete != that.cascadeDelete)
            return false;
        return true;
    }

    @Override
    ReferenceSchemaField toSchemaItem(JSimpleDB jdb) {
        final ReferenceSchemaField schemaField = new ReferenceSchemaField();
        super.initialize(jdb, schemaField);
        schemaField.setOnDelete(this.onDelete);
        schemaField.setCascadeDelete(this.cascadeDelete);
        final TreeSet objectTypes = new TreeSet<>();
        for (JClass jclass : jdb.getJClasses(this.typeToken.getRawType()))
            objectTypes.add(jclass.storageId);
        schemaField.setObjectTypes(objectTypes);
        return schemaField;
    }

    @Override
    JReferenceFieldInfo toJFieldInfo(int parentStorageId) {
        return new JReferenceFieldInfo(this, parentStorageId);
    }

// Bytecode generation

    @Override
    void outputMethods(final ClassGenerator generator, ClassWriter cw) {

        //
        // Getter:
        //
        //  Object value = this.readCoreAPIValue();
        //  if (value == null)
        //      return null;
        //  ObjId id = (ObjId)value;
        //  return this.tx.get(id);
        //
        MethodVisitor mv = cw.visitMethod(
          this.getter.getModifiers() & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED),
          this.getter.getName(), Type.getMethodDescriptor(this.getter), null, generator.getExceptionNames(this.getter));
        this.outputReadCoreValueBytecode(generator, mv);
        mv.visitInsn(Opcodes.DUP);
        final Label label1 = new Label();
        mv.visitJumpInsn(Opcodes.IFNONNULL, label1);
        mv.visitInsn(Opcodes.POP);
        mv.visitInsn(Opcodes.ACONST_NULL);
        mv.visitInsn(Opcodes.ARETURN);
        mv.visitLabel(label1);
        mv.visitFrame(Opcodes.F_SAME1, 0, new Object[0], 1, new String[] { Type.getInternalName(Object.class) });
        mv.visitTypeInsn(Opcodes.CHECKCAST, Type.getInternalName(ObjId.class));
        mv.visitVarInsn(Opcodes.ALOAD, 0);
        mv.visitFieldInsn(Opcodes.GETFIELD, generator.getClassName(),
          ClassGenerator.TX_FIELD_NAME, Type.getDescriptor(JTransaction.class));
        mv.visitInsn(Opcodes.SWAP);
        generator.emitInvoke(mv, ClassGenerator.GET_METHOD);
        mv.visitTypeInsn(Opcodes.CHECKCAST, Type.getInternalName(this.getter.getReturnType()));
        mv.visitInsn(Opcodes.ARETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();

        //
        // Setter:
        //
        //  ObjId id;
        //  if (jobj == null)
        //      id = null;
        //  else
        //      id = jobj.getObjId();
        //  this.writeCoreAPIValue(id);
        //
        mv = cw.visitMethod(
          this.setter.getModifiers() & (Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED),
          this.setter.getName(), Type.getMethodDescriptor(this.setter), null, generator.getExceptionNames(this.setter));
        mv.visitVarInsn(Opcodes.ALOAD, 1);
        final Label label2 = new Label();
        final Label label3 = new Label();
        mv.visitJumpInsn(Opcodes.IFNONNULL, label2);
        mv.visitInsn(Opcodes.ACONST_NULL);
        mv.visitJumpInsn(Opcodes.GOTO, label3);
        mv.visitLabel(label2);
        mv.visitFrame(Opcodes.F_SAME, 0, new Object[0], 0, new Object[0]);
        mv.visitVarInsn(Opcodes.ALOAD, 1);
        generator.emitInvoke(mv, ClassGenerator.JOBJECT_GET_OBJ_ID_METHOD);
        mv.visitLabel(label3);
        mv.visitFrame(Opcodes.F_SAME1, 0, new Object[0], 1, new String[] { Type.getInternalName(ObjId.class) });
        //mv.visitTypeInsn(Opcodes.CHECKCAST, Type.getInternalName(ObjId.class));
        this.outputWriteCoreValueBytecode(generator, mv);
        mv.visitInsn(Opcodes.RETURN);
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }
}