Scala example source code file (Printer.java)

This example Scala source code file (Printer.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

asm, attribute, handle_tag, label, list, object, opcodes, printer, string, stringbuffer, types

The Printer.java Scala example source code

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package scala.tools.asm.util;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import scala.tools.asm.Attribute;
import scala.tools.asm.Handle;
import scala.tools.asm.Label;
import scala.tools.asm.Opcodes;

/**
 * An abstract converter from visit events to text.
 *
 * @author Eric Bruneton
 */
public abstract class Printer {

    /**
     * The names of the Java Virtual Machine opcodes.
     */
    public static final String[] OPCODES;

    /**
     * The names of the for <code>operand</code> parameter values of the
     * {@link scala.tools.asm.MethodVisitor#visitIntInsn} method when
     * <code>opcode</code> is <code>NEWARRAY</code>.
     */
    public static final String[] TYPES;

    /**
     * The names of the <code>tag</code> field values for
     * {@link scala.tools.asm.Handle}.
     */
    public static final String[] HANDLE_TAG;

    static {
        String s = "NOP,ACONST_NULL,ICONST_M1,ICONST_0,ICONST_1,ICONST_2,"
                + "ICONST_3,ICONST_4,ICONST_5,LCONST_0,LCONST_1,FCONST_0,"
                + "FCONST_1,FCONST_2,DCONST_0,DCONST_1,BIPUSH,SIPUSH,LDC,,,"
                + "ILOAD,LLOAD,FLOAD,DLOAD,ALOAD,,,,,,,,,,,,,,,,,,,,,IALOAD,"
                + "LALOAD,FALOAD,DALOAD,AALOAD,BALOAD,CALOAD,SALOAD,ISTORE,"
                + "LSTORE,FSTORE,DSTORE,ASTORE,,,,,,,,,,,,,,,,,,,,,IASTORE,"
                + "LASTORE,FASTORE,DASTORE,AASTORE,BASTORE,CASTORE,SASTORE,POP,"
                + "POP2,DUP,DUP_X1,DUP_X2,DUP2,DUP2_X1,DUP2_X2,SWAP,IADD,LADD,"
                + "FADD,DADD,ISUB,LSUB,FSUB,DSUB,IMUL,LMUL,FMUL,DMUL,IDIV,LDIV,"
                + "FDIV,DDIV,IREM,LREM,FREM,DREM,INEG,LNEG,FNEG,DNEG,ISHL,LSHL,"
                + "ISHR,LSHR,IUSHR,LUSHR,IAND,LAND,IOR,LOR,IXOR,LXOR,IINC,I2L,"
                + "I2F,I2D,L2I,L2F,L2D,F2I,F2L,F2D,D2I,D2L,D2F,I2B,I2C,I2S,LCMP,"
                + "FCMPL,FCMPG,DCMPL,DCMPG,IFEQ,IFNE,IFLT,IFGE,IFGT,IFLE,"
                + "IF_ICMPEQ,IF_ICMPNE,IF_ICMPLT,IF_ICMPGE,IF_ICMPGT,IF_ICMPLE,"
                + "IF_ACMPEQ,IF_ACMPNE,GOTO,JSR,RET,TABLESWITCH,LOOKUPSWITCH,"
                + "IRETURN,LRETURN,FRETURN,DRETURN,ARETURN,RETURN,GETSTATIC,"
                + "PUTSTATIC,GETFIELD,PUTFIELD,INVOKEVIRTUAL,INVOKESPECIAL,"
                + "INVOKESTATIC,INVOKEINTERFACE,INVOKEDYNAMIC,NEW,NEWARRAY,"
                + "ANEWARRAY,ARRAYLENGTH,ATHROW,CHECKCAST,INSTANCEOF,"
                + "MONITORENTER,MONITOREXIT,,MULTIANEWARRAY,IFNULL,IFNONNULL,";
        OPCODES = new String[200];
        int i = 0;
        int j = 0;
        int l;
        while ((l = s.indexOf(',', j)) > 0) {
            OPCODES[i++] = j + 1 == l ? null : s.substring(j, l);
            j = l + 1;
        }

        s = "T_BOOLEAN,T_CHAR,T_FLOAT,T_DOUBLE,T_BYTE,T_SHORT,T_INT,T_LONG,";
        TYPES = new String[12];
        j = 0;
        i = 4;
        while ((l = s.indexOf(',', j)) > 0) {
            TYPES[i++] = s.substring(j, l);
            j = l + 1;
        }

        s = "H_GETFIELD,H_GETSTATIC,H_PUTFIELD,H_PUTSTATIC,"
                + "H_INVOKEVIRTUAL,H_INVOKESTATIC,H_INVOKESPECIAL,"
                + "H_NEWINVOKESPECIAL,H_INVOKEINTERFACE,";
        HANDLE_TAG = new String[10];
        j = 0;
        i = 1;
        while ((l = s.indexOf(',', j)) > 0) {
            HANDLE_TAG[i++] = s.substring(j, l);
            j = l + 1;
        }
    }

    /**
     * The ASM API version implemented by this class. The value of this field
     * must be one of {@link Opcodes#ASM4}.
     */
    protected final int api;

    /**
     * A buffer that can be used to create strings.
     */
    protected final StringBuffer buf;

    /**
     * The text to be printed. Since the code of methods is not necessarily
     * visited in sequential order, one method after the other, but can be
     * interlaced (some instructions from method one, then some instructions
     * from method two, then some instructions from method one again...), it is
     * not possible to print the visited instructions directly to a sequential
     * stream. A class is therefore printed in a two steps process: a string
     * tree is constructed during the visit, and printed to a sequential stream
     * at the end of the visit. This string tree is stored in this field, as a
     * string list that can contain other string lists, which can themselves
     * contain other string lists, and so on.
     */
    public final List<Object> text;

    /**
     * Constructs a new {@link Printer}.
     */
    protected Printer(final int api) {
        this.api = api;
        this.buf = new StringBuffer();
        this.text = new ArrayList<Object>();
    }

    /**
     * Class header. See {@link scala.tools.asm.ClassVisitor#visit}.
     */
    public abstract void visit(final int version, final int access,
            final String name, final String signature, final String superName,
            final String[] interfaces);

    /**
     * Class source. See {@link scala.tools.asm.ClassVisitor#visitSource}.
     */
    public abstract void visitSource(final String file, final String debug);

    /**
     * Class outer class. See
     * {@link scala.tools.asm.ClassVisitor#visitOuterClass}.
     */
    public abstract void visitOuterClass(final String owner, final String name,
            final String desc);

    /**
     * Class annotation. See
     * {@link scala.tools.asm.ClassVisitor#visitAnnotation}.
     */
    public abstract Printer visitClassAnnotation(final String desc,
            final boolean visible);

    /**
     * Class attribute. See
     * {@link scala.tools.asm.ClassVisitor#visitAttribute}.
     */
    public abstract void visitClassAttribute(final Attribute attr);

    /**
     * Class inner name. See
     * {@link scala.tools.asm.ClassVisitor#visitInnerClass}.
     */
    public abstract void visitInnerClass(final String name,
            final String outerName, final String innerName, final int access);

    /**
     * Class field. See {@link scala.tools.asm.ClassVisitor#visitField}.
     */
    public abstract Printer visitField(final int access, final String name,
            final String desc, final String signature, final Object value);

    /**
     * Class method. See {@link scala.tools.asm.ClassVisitor#visitMethod}.
     */
    public abstract Printer visitMethod(final int access, final String name,
            final String desc, final String signature, final String[] exceptions);

    /**
     * Class end. See {@link scala.tools.asm.ClassVisitor#visitEnd}.
     */
    public abstract void visitClassEnd();

    // ------------------------------------------------------------------------
    // Annotations
    // ------------------------------------------------------------------------

    /**
     * Annotation value. See {@link scala.tools.asm.AnnotationVisitor#visit}.
     */
    public abstract void visit(final String name, final Object value);

    /**
     * Annotation enum value. See
     * {@link scala.tools.asm.AnnotationVisitor#visitEnum}.
     */
    public abstract void visitEnum(final String name, final String desc,
            final String value);

    /**
     * Nested annotation value. See
     * {@link scala.tools.asm.AnnotationVisitor#visitAnnotation}.
     */
    public abstract Printer visitAnnotation(final String name, final String desc);

    /**
     * Annotation array value. See
     * {@link scala.tools.asm.AnnotationVisitor#visitArray}.
     */
    public abstract Printer visitArray(final String name);

    /**
     * Annotation end. See {@link scala.tools.asm.AnnotationVisitor#visitEnd}.
     */
    public abstract void visitAnnotationEnd();

    // ------------------------------------------------------------------------
    // Fields
    // ------------------------------------------------------------------------

    /**
     * Field annotation. See
     * {@link scala.tools.asm.FieldVisitor#visitAnnotation}.
     */
    public abstract Printer visitFieldAnnotation(final String desc,
            final boolean visible);

    /**
     * Field attribute. See
     * {@link scala.tools.asm.FieldVisitor#visitAttribute}.
     */
    public abstract void visitFieldAttribute(final Attribute attr);

    /**
     * Field end. See {@link scala.tools.asm.FieldVisitor#visitEnd}.
     */
    public abstract void visitFieldEnd();

    // ------------------------------------------------------------------------
    // Methods
    // ------------------------------------------------------------------------

    /**
     * Method default annotation. See
     * {@link scala.tools.asm.MethodVisitor#visitAnnotationDefault}.
     */
    public abstract Printer visitAnnotationDefault();

    /**
     * Method annotation. See
     * {@link scala.tools.asm.MethodVisitor#visitAnnotation}.
     */
    public abstract Printer visitMethodAnnotation(final String desc,
            final boolean visible);

    /**
     * Method parameter annotation. See
     * {@link scala.tools.asm.MethodVisitor#visitParameterAnnotation}.
     */
    public abstract Printer visitParameterAnnotation(final int parameter,
            final String desc, final boolean visible);

    /**
     * Method attribute. See
     * {@link scala.tools.asm.MethodVisitor#visitAttribute}.
     */
    public abstract void visitMethodAttribute(final Attribute attr);

    /**
     * Method start. See {@link scala.tools.asm.MethodVisitor#visitCode}.
     */
    public abstract void visitCode();

    /**
     * Method stack frame. See
     * {@link scala.tools.asm.MethodVisitor#visitFrame}.
     */
    public abstract void visitFrame(final int type, final int nLocal,
            final Object[] local, final int nStack, final Object[] stack);

    /**
     * Method instruction. See {@link scala.tools.asm.MethodVisitor#visitInsn}
     * .
     */
    public abstract void visitInsn(final int opcode);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitIntInsn}.
     */
    public abstract void visitIntInsn(final int opcode, final int operand);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitVarInsn}.
     */
    public abstract void visitVarInsn(final int opcode, final int var);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitTypeInsn}.
     */
    public abstract void visitTypeInsn(final int opcode, final String type);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitFieldInsn}.
     */
    public abstract void visitFieldInsn(final int opcode, final String owner,
            final String name, final String desc);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitMethodInsn}.
     */
    public abstract void visitMethodInsn(final int opcode, final String owner,
            final String name, final String desc);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitInvokeDynamicInsn}.
     */
    public abstract void visitInvokeDynamicInsn(String name, String desc,
            Handle bsm, Object... bsmArgs);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitJumpInsn}.
     */
    public abstract void visitJumpInsn(final int opcode, final Label label);

    /**
     * Method label. See {@link scala.tools.asm.MethodVisitor#visitLabel}.
     */
    public abstract void visitLabel(final Label label);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitLdcInsn}.
     */
    public abstract void visitLdcInsn(final Object cst);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitIincInsn}.
     */
    public abstract void visitIincInsn(final int var, final int increment);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitTableSwitchInsn}.
     */
    public abstract void visitTableSwitchInsn(final int min, final int max,
            final Label dflt, final Label... labels);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitLookupSwitchInsn}.
     */
    public abstract void visitLookupSwitchInsn(final Label dflt,
            final int[] keys, final Label[] labels);

    /**
     * Method instruction. See
     * {@link scala.tools.asm.MethodVisitor#visitMultiANewArrayInsn}.
     */
    public abstract void visitMultiANewArrayInsn(final String desc,
            final int dims);

    /**
     * Method exception handler. See
     * {@link scala.tools.asm.MethodVisitor#visitTryCatchBlock}.
     */
    public abstract void visitTryCatchBlock(final Label start, final Label end,
            final Label handler, final String type);

    /**
     * Method debug info. See
     * {@link scala.tools.asm.MethodVisitor#visitLocalVariable}.
     */
    public abstract void visitLocalVariable(final String name,
            final String desc, final String signature, final Label start,
            final Label end, final int index);

    /**
     * Method debug info. See
     * {@link scala.tools.asm.MethodVisitor#visitLineNumber}.
     */
    public abstract void visitLineNumber(final int line, final Label start);

    /**
     * Method max stack and max locals. See
     * {@link scala.tools.asm.MethodVisitor#visitMaxs}.
     */
    public abstract void visitMaxs(final int maxStack, final int maxLocals);

    /**
     * Method end. See {@link scala.tools.asm.MethodVisitor#visitEnd}.
     */
    public abstract void visitMethodEnd();

    /**
     * Returns the text constructed by this visitor.
     *
     * @return the text constructed by this visitor.
     */
    public List<Object> getText() {
        return text;
    }

    /**
     * Prints the text constructed by this visitor.
     *
     * @param pw
     *            the print writer to be used.
     */
    public void print(final PrintWriter pw) {
        printList(pw, text);
    }

    /**
     * Appends a quoted string to a given buffer.
     *
     * @param buf
     *            the buffer where the string must be added.
     * @param s
     *            the string to be added.
     */
    public static void appendString(final StringBuffer buf, final String s) {
        buf.append('\"');
        for (int i = 0; i < s.length(); ++i) {
            char c = s.charAt(i);
            if (c == '\n') {
                buf.append("\\n");
            } else if (c == '\r') {
                buf.append("\\r");
            } else if (c == '\\') {
                buf.append("\\\\");
            } else if (c == '"') {
                buf.append("\\\"");
            } else if (c < 0x20 || c > 0x7f) {
                buf.append("\\u");
                if (c < 0x10) {
                    buf.append("000");
                } else if (c < 0x100) {
                    buf.append("00");
                } else if (c < 0x1000) {
                    buf.append('0');
                }
                buf.append(Integer.toString(c, 16));
            } else {
                buf.append(c);
            }
        }
        buf.append('\"');
    }

    /**
     * Prints the given string tree.
     *
     * @param pw
     *            the writer to be used to print the tree.
     * @param l
     *            a string tree, i.e., a string list that can contain other
     *            string lists, and so on recursively.
     */
    static void printList(final PrintWriter pw, final List<?> l) {
        for (int i = 0; i < l.size(); ++i) {
            Object o = l.get(i);
            if (o instanceof List) {
                printList(pw, (List<?>) o);
            } else {
                pw.print(o.toString());
            }
        }
    }
}