Example usage for org.objectweb.asm MethodVisitor visitInsn

Introduction

In this page you can find the example usage for org.objectweb.asm MethodVisitor visitInsn.

Prototype

public void visitInsn(final int opcode) 

Source Link

Document

Visits a zero operand instruction.

Usage

From source file:com.nginious.http.xsp.expr.ExpressionCompiler.java

License:Apache License

/**
 * Creates a compiled expression from the specified tree value node expression. The class bytecode for the 
 * compiled expression is generated at runtime.
 * /*from w w w.  j a va  2 s  .  co  m*/
 * @param uncompiled the uncompiled tree value node expression
 * @return the compiled expression
 * @throws ExpressionException if unable to compile expression
 */
public Expression compile(TreeExpression uncompiled) throws ExpressionException {
    ClassWriter writer = new ClassWriter(0);

    // Create class
    String className = classBaseName + classNameCounter.getAndIncrement();
    String classIdentifier = className.replace('.', '/');
    writer.visit(Opcodes.V1_6, Opcodes.ACC_PUBLIC, classIdentifier, "L" + classIdentifier + ";",
            "com/nginious/http/xsp/expr/Expression", null);

    // Create constructor
    MethodVisitor visitor = writer.visitMethod(Opcodes.ACC_PROTECTED, "<init>", "()V", null, null);
    visitor.visitCode();
    visitor.visitVarInsn(Opcodes.ALOAD, 0);
    visitor.visitMethodInsn(Opcodes.INVOKESPECIAL, "com/nginious/http/xsp/expr/Expression", "<init>", "()V");
    visitor.visitInsn(Opcodes.RETURN);
    visitor.visitMaxs(1, 1);
    visitor.visitEnd();

    // protected abstract boolean evaluateBoolean();
    visitor = writer.visitMethod(Opcodes.ACC_PROTECTED, "evaluateBoolean", "()Z", null, null);

    if (uncompiled.getType() == Type.BOOLEAN) {
        uncompiled.compile(visitor);
    } else if (uncompiled.getType() == Type.DOUBLE) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateDouble", "()D");

        Label endLabel = new Label();
        Label falseLabel = new Label();
        visitor.visitLdcInsn(0.0d);
        visitor.visitInsn(Opcodes.DCMPL);
        visitor.visitJumpInsn(Opcodes.IFEQ, falseLabel);
        visitor.visitLdcInsn(true);
        visitor.visitJumpInsn(Opcodes.GOTO, endLabel);
        visitor.visitLabel(falseLabel);
        visitor.visitLdcInsn(false);
        visitor.visitLabel(endLabel);
    } else if (uncompiled.getType() == Type.INT) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateInt", "()I");

        Label endLabel = new Label();
        Label falseLabel = new Label();
        visitor.visitLdcInsn(0);
        visitor.visitJumpInsn(Opcodes.IFNE, falseLabel);
        visitor.visitLdcInsn(true);
        visitor.visitJumpInsn(Opcodes.GOTO, endLabel);
        visitor.visitLabel(falseLabel);
        visitor.visitLdcInsn(false);
        visitor.visitLabel(endLabel);
    } else if (uncompiled.getType() == Type.STRING) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateString",
                "()Ljava/lang/String;");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "parseBoolean",
                "(Ljava/lang/String;)Z");
    }

    visitor.visitInsn(Opcodes.IRETURN);
    visitor.visitMaxs(5, 5);
    visitor.visitEnd();

    // protected abstract int evaluateInt();
    visitor = writer.visitMethod(Opcodes.ACC_PROTECTED, "evaluateInt", "()I", null, null);

    if (uncompiled.getType() == Type.BOOLEAN) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateBoolean", "()Z");

        Label endLabel = new Label();
        Label falseLabel = new Label();
        visitor.visitJumpInsn(Opcodes.IFEQ, falseLabel);
        visitor.visitLdcInsn(1);
        visitor.visitJumpInsn(Opcodes.GOTO, endLabel);
        visitor.visitLabel(falseLabel);
        visitor.visitLdcInsn(0);
        visitor.visitLabel(endLabel);
    } else if (uncompiled.getType() == Type.DOUBLE) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateDouble", "()D");
        visitor.visitInsn(Opcodes.D2I);
    } else if (uncompiled.getType() == Type.INT) {
        uncompiled.compile(visitor);
    } else if (uncompiled.getType() == Type.STRING) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateString",
                "()Ljava/lang/String;");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "parseInt", "(Ljava/lang/String;)I");
    }

    visitor.visitInsn(Opcodes.IRETURN);
    visitor.visitMaxs(5, 5);
    visitor.visitEnd();

    // protected abstract double evaluateDouble();
    visitor = writer.visitMethod(Opcodes.ACC_PROTECTED, "evaluateDouble", "()D", null, null);

    if (uncompiled.getType() == Type.BOOLEAN) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateBoolean", "()Z");

        Label endLabel = new Label();
        Label falseLabel = new Label();
        visitor.visitJumpInsn(Opcodes.IFEQ, falseLabel);
        visitor.visitLdcInsn(1.0d);
        visitor.visitJumpInsn(Opcodes.GOTO, endLabel);
        visitor.visitLabel(falseLabel);
        visitor.visitLdcInsn(0.0d);
        visitor.visitLabel(endLabel);
    } else if (uncompiled.getType() == Type.DOUBLE) {
        uncompiled.compile(visitor);
    } else if (uncompiled.getType() == Type.INT) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateInt", "()I");
        visitor.visitInsn(Opcodes.I2D);
    } else if (uncompiled.getType() == Type.STRING) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateString",
                "()Ljava/lang/String;");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "parseDouble",
                "(Ljava/lang/String;)D");
    }

    visitor.visitInsn(Opcodes.DRETURN);
    visitor.visitMaxs(5, 5);
    visitor.visitEnd();

    // protected abstract String evaluateString();
    visitor = writer.visitMethod(Opcodes.ACC_PROTECTED, "evaluateString", "()Ljava/lang/String;", null, null);

    if (uncompiled.getType() == Type.BOOLEAN) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateBoolean", "()Z");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "toString", "(Z)Ljava/lang/String;");
    } else if (uncompiled.getType() == Type.DOUBLE) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateDouble", "()D");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "toString", "(D)Ljava/lang/String;");
    } else if (uncompiled.getType() == Type.INT) {
        visitor.visitVarInsn(Opcodes.ALOAD, 0); // this
        visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, classIdentifier, "evaluateInt", "()I");
        visitor.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "toString", "(I)Ljava/lang/String;");
    } else if (uncompiled.getType() == Type.STRING) {
        uncompiled.compile(visitor);
    }

    visitor.visitInsn(Opcodes.ARETURN);
    visitor.visitMaxs(6, 6);
    visitor.visitEnd();

    // public abstract Type getType();        
    visitor = writer.visitMethod(Opcodes.ACC_PUBLIC, "getType", "()Lcom/nginious/http/xsp/expr/Type;", null,
            null);

    if (uncompiled.getType() == Type.BOOLEAN) {
        visitor.visitFieldInsn(Opcodes.GETSTATIC, "com/nginious/http/xsp/expr/Type", "BOOLEAN",
                "Lcom/nginious/http/xsp/expr/Type;");
        visitor.visitInsn(Opcodes.ARETURN);
    } else if (uncompiled.getType() == Type.DOUBLE) {
        visitor.visitFieldInsn(Opcodes.GETSTATIC, "com/nginious/http/xsp/expr/Type", "DOUBLE",
                "Lcom/nginious/http/xsp/expr/Type;");
        visitor.visitInsn(Opcodes.ARETURN);
    } else if (uncompiled.getType() == Type.INT) {
        visitor.visitFieldInsn(Opcodes.GETSTATIC, "com/nginious/http/xsp/expr/Type", "INT",
                "Lcom/nginious/http/xsp/expr/Type;");
        visitor.visitInsn(Opcodes.ARETURN);
    } else if (uncompiled.getType() == Type.STRING) {
        visitor.visitFieldInsn(Opcodes.GETSTATIC, "com/nginious/http/xsp/expr/Type", "STRING",
                "Lcom/nginious/http/xsp/expr/Type;");
        visitor.visitInsn(Opcodes.ARETURN);
    }

    visitor.visitMaxs(1, 1);
    visitor.visitEnd();

    try {
        writer.visitEnd();
        byte[] clazzBytes = writer.toByteArray();
        Class<?> clazz = loadClass(className, clazzBytes);
        return (Expression) clazz.newInstance();
    } catch (Exception e) {
        throw new ExpressionException("Can't instantiate compiled expression", e);
    }
}

---

From source file:com.nginious.http.xsp.expr.LeftFunction.java

License:Apache License

/**
 * Creates bytecode for evaluating this left function. The specified method visitor
 * and type are used for generating bytecode.
 * //from w ww .  jav  a 2 s .  c o  m
 * @param visitor the method visitor
 * @param type the type
 */
void compile(MethodVisitor visitor, Type type) {
    value.compile(visitor, Type.STRING);
    visitor.visitVarInsn(Opcodes.ASTORE, 1);

    Label nullLabel = new Label();
    Label notNullLabel = new Label();

    visitor.visitVarInsn(Opcodes.ALOAD, 1);
    visitor.visitJumpInsn(Opcodes.IFNULL, nullLabel);

    visitor.visitVarInsn(Opcodes.ALOAD, 1);
    visitor.visitLdcInsn(0);
    value2.compile(visitor, Type.INT);
    visitor.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "substring", "(II)Ljava/lang/String;");
    visitor.visitJumpInsn(Opcodes.GOTO, notNullLabel);

    visitor.visitLabel(nullLabel);
    visitor.visitInsn(Opcodes.ACONST_NULL);

    visitor.visitLabel(notNullLabel);
}

---

From source file:com.nginious.http.xsp.expr.LessEqualsOperator.java

License:Apache License

/**
 * Creates bytecode for evaluating the argument values as doubles. The bytecode
 * is generated using the specified method visitor.
 * /*w w  w.j  a v  a  2 s .c  om*/
 * @param visitor the method visitor
 */
private void compileDouble(MethodVisitor visitor) {
    Label labelFalse = new Label();
    Label labelEnd = new Label();

    value2.compile(visitor, Type.DOUBLE);
    value1.compile(visitor, Type.DOUBLE);

    visitor.visitInsn(Opcodes.DCMPL);
    visitor.visitJumpInsn(Opcodes.IFLT, labelFalse);

    // True
    visitor.visitLdcInsn(true);
    visitor.visitJumpInsn(Opcodes.GOTO, labelEnd);

    // False
    visitor.visitLabel(labelFalse);
    visitor.visitLdcInsn(false);

    visitor.visitLabel(labelEnd);
}

---

From source file:com.nginious.http.xsp.expr.LessOperator.java

License:Apache License

/**
 * Creates bytecode for evaluating the argument values as doubles. The bytecode
 * is generated using the specified method visitor.
 * //w w w  .ja va2  s. c  om
 * @param visitor the method visitor
 */
private void compileDouble(MethodVisitor visitor) {
    Label labelFalse = new Label();
    Label labelEnd = new Label();

    value2.compile(visitor, Type.DOUBLE);
    value1.compile(visitor, Type.DOUBLE);

    visitor.visitInsn(Opcodes.DCMPL);
    visitor.visitJumpInsn(Opcodes.IFLE, labelFalse);

    // True
    visitor.visitLdcInsn(true);
    visitor.visitJumpInsn(Opcodes.GOTO, labelEnd);

    // False
    visitor.visitLabel(labelFalse);
    visitor.visitLdcInsn(false);

    visitor.visitLabel(labelEnd);
}

---

From source file:com.nginious.http.xsp.expr.ModOperator.java

License:Apache License

/**
 * Creats bytecode for calculating the result for this operator. The bytecode
 * is generated using the specified method visitor. The result is generated
 * as the specified type./*from  w ww  .  j  ava 2s  .c  o  m*/
 * 
 * @param visitor the method visitor
 * @param type the type
 */
void compile(MethodVisitor visitor, Type type) {
    type = resolveType(this.value1, this.value2);
    value1.compile(visitor, type);
    value2.compile(visitor, type);

    if (type == Type.DOUBLE) {
        visitor.visitInsn(Opcodes.DREM);
    } else {
        visitor.visitInsn(Opcodes.IREM);
    }
}

---

From source file:com.nginious.http.xsp.expr.MoreEqualsOperator.java

License:Apache License

/**
 * Creates bytecode for evaluating the argument values as doubles. The bytecode
 * is generated using the specified method visitor.
 * /* w w w  .  j  av  a  2  s .com*/
 * @param visitor the method visitor
 */
private void compileDouble(MethodVisitor visitor) {
    Label labelFalse = new Label();
    Label labelEnd = new Label();

    value1.compile(visitor, Type.DOUBLE);
    value2.compile(visitor, Type.DOUBLE);

    visitor.visitInsn(Opcodes.DCMPL);
    visitor.visitJumpInsn(Opcodes.IFLT, labelFalse);

    // True
    visitor.visitLdcInsn(true);
    visitor.visitJumpInsn(Opcodes.GOTO, labelEnd);

    // False
    visitor.visitLabel(labelFalse);
    visitor.visitLdcInsn(false);

    visitor.visitLabel(labelEnd);
}

---

From source file:com.nginious.http.xsp.expr.MoreOperator.java

License:Apache License

/**
 * Creates bytecode for evaluating the argument values as doubles. The bytecode
 * is generated using the specified method visitor.
 * //from   w  w w. ja v a2 s .  c o m
 * @param visitor the method visitor
 */
private void compileDouble(MethodVisitor visitor) {
    Label labelFalse = new Label();
    Label labelEnd = new Label();

    value1.compile(visitor, Type.DOUBLE);
    value2.compile(visitor, Type.DOUBLE);

    visitor.visitInsn(Opcodes.DCMPL);
    visitor.visitJumpInsn(Opcodes.IFLE, labelFalse);

    // True
    visitor.visitLdcInsn(true);
    visitor.visitJumpInsn(Opcodes.GOTO, labelEnd);

    // False
    visitor.visitLabel(labelFalse);
    visitor.visitLdcInsn(false);

    visitor.visitLabel(labelEnd);
}

---

From source file:com.nginious.http.xsp.expr.MulOperator.java

License:Apache License

/**
 * Creates bytecode for evaluating this operator. The bytecode is created
 * using the specified method visitor. The bytecode produces a result
 * of the specified type./*  ww  w . j  av  a  2  s.c  o m*/
 * 
 * @param visitor the method visitor
 * @param type the result type
 */
void compile(MethodVisitor visitor, Type type) {
    type = resolveType(this.value1, this.value2);
    value1.compile(visitor, type);
    value2.compile(visitor, type);

    if (type == Type.DOUBLE) {
        visitor.visitInsn(Opcodes.DMUL);
    } else {
        visitor.visitInsn(Opcodes.IMUL);
    }
}

---

From source file:com.nginious.http.xsp.expr.NotEqualsOperator.java

License:Apache License

/**
 * Compiles bytecode for evaluating this not equals operator producing
 * a double as result. The specified method visitor is used for generating
 * bytecode.//from ww  w. ja va2s. c om
 * 
 * @param visitor the method visitor
 */
private void compileDouble(MethodVisitor visitor) {
    Label trueLabel = new Label();
    Label falseLabel = new Label();

    value1.compile(visitor, Type.DOUBLE);
    value2.compile(visitor, Type.DOUBLE);
    visitor.visitInsn(Opcodes.DCMPL);
    visitor.visitJumpInsn(Opcodes.IFEQ, trueLabel);

    visitor.visitLdcInsn(true);
    visitor.visitJumpInsn(Opcodes.GOTO, falseLabel);

    visitor.visitLabel(trueLabel);
    visitor.visitLdcInsn(false);

    visitor.visitLabel(falseLabel);
}

---

From source file:com.nginious.http.xsp.expr.NullValue.java

License:Apache License

/**
 * Creates bytecode for this null value. The bytecode is generated using the specified method 
 * visitor. The result of the evaluation produces the specified type.
 * /*from ww w .  j a v  a2  s  . com*/
 * @param visitor the method visitor
 * @param type the type
 */
void compile(MethodVisitor visitor, Type type) {
    if (type == Type.STRING) {
        visitor.visitInsn(Opcodes.ACONST_NULL);
    } else if (type == Type.INT) {
        visitor.visitLdcInsn(0);
    } else if (type == Type.DOUBLE) {
        visitor.visitLdcInsn(0.0d);
    }
}

---

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