Scala example source code file (SignatureReader.java)

This example Scala source code file (SignatureReader.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, b, c, d, i, l, s, signaturereader, signaturevisitor, string, t

The SignatureReader.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.signature;

/**
 * A type signature parser to make a signature visitor visit an existing
 * signature.
 *
 * @author Thomas Hallgren
 * @author Eric Bruneton
 */
public class SignatureReader {

    /**
     * The signature to be read.
     */
    private final String signature;

    /**
     * Constructs a {@link SignatureReader} for the given signature.
     *
     * @param signature
     *            A <i>ClassSignature</i>, <i>MethodTypeSignature</i>, or
     *            <i>FieldTypeSignature</i>.
     */
    public SignatureReader(final String signature) {
        this.signature = signature;
    }

    /**
     * Makes the given visitor visit the signature of this
     * {@link SignatureReader}. This signature is the one specified in the
     * constructor (see {@link #SignatureReader(String) SignatureReader}). This
     * method is intended to be called on a {@link SignatureReader} that was
     * created using a <i>ClassSignature</i> (such as the <code>signature</code>
     * parameter of the {@link scala.tools.asm.ClassVisitor#visit
     * ClassVisitor.visit} method) or a <i>MethodTypeSignature</i> (such as the
     * <code>signature</code> parameter of the
     * {@link scala.tools.asm.ClassVisitor#visitMethod
     * ClassVisitor.visitMethod} method).
     *
     * @param v
     *            the visitor that must visit this signature.
     */
    public void accept(final SignatureVisitor v) {
        String signature = this.signature;
        int len = signature.length();
        int pos;
        char c;

        if (signature.charAt(0) == '<') {
            pos = 2;
            do {
                int end = signature.indexOf(':', pos);
                v.visitFormalTypeParameter(signature.substring(pos - 1, end));
                pos = end + 1;

                c = signature.charAt(pos);
                if (c == 'L' || c == '[' || c == 'T') {
                    pos = parseType(signature, pos, v.visitClassBound());
                }

                while ((c = signature.charAt(pos++)) == ':') {
                    pos = parseType(signature, pos, v.visitInterfaceBound());
                }
            } while (c != '>');
        } else {
            pos = 0;
        }

        if (signature.charAt(pos) == '(') {
            pos++;
            while (signature.charAt(pos) != ')') {
                pos = parseType(signature, pos, v.visitParameterType());
            }
            pos = parseType(signature, pos + 1, v.visitReturnType());
            while (pos < len) {
                pos = parseType(signature, pos + 1, v.visitExceptionType());
            }
        } else {
            pos = parseType(signature, pos, v.visitSuperclass());
            while (pos < len) {
                pos = parseType(signature, pos, v.visitInterface());
            }
        }
    }

    /**
     * Makes the given visitor visit the signature of this
     * {@link SignatureReader}. This signature is the one specified in the
     * constructor (see {@link #SignatureReader(String) SignatureReader}). This
     * method is intended to be called on a {@link SignatureReader} that was
     * created using a <i>FieldTypeSignature</i>, such as the
     * <code>signature</code> parameter of the
     * {@link scala.tools.asm.ClassVisitor#visitField ClassVisitor.visitField}
     * or {@link scala.tools.asm.MethodVisitor#visitLocalVariable
     * MethodVisitor.visitLocalVariable} methods.
     *
     * @param v
     *            the visitor that must visit this signature.
     */
    public void acceptType(final SignatureVisitor v) {
        parseType(this.signature, 0, v);
    }

    /**
     * Parses a field type signature and makes the given visitor visit it.
     *
     * @param signature
     *            a string containing the signature that must be parsed.
     * @param pos
     *            index of the first character of the signature to parsed.
     * @param v
     *            the visitor that must visit this signature.
     * @return the index of the first character after the parsed signature.
     */
    private static int parseType(final String signature, int pos,
            final SignatureVisitor v) {
        char c;
        int start, end;
        boolean visited, inner;
        String name;

        switch (c = signature.charAt(pos++)) {
        case 'Z':
        case 'C':
        case 'B':
        case 'S':
        case 'I':
        case 'F':
        case 'J':
        case 'D':
        case 'V':
            v.visitBaseType(c);
            return pos;

        case '[':
            return parseType(signature, pos, v.visitArrayType());

        case 'T':
            end = signature.indexOf(';', pos);
            v.visitTypeVariable(signature.substring(pos, end));
            return end + 1;

        default: // case 'L':
            start = pos;
            visited = false;
            inner = false;
            for (;;) {
                switch (c = signature.charAt(pos++)) {
                case '.':
                case ';':
                    if (!visited) {
                        name = signature.substring(start, pos - 1);
                        if (inner) {
                            v.visitInnerClassType(name);
                        } else {
                            v.visitClassType(name);
                        }
                    }
                    if (c == ';') {
                        v.visitEnd();
                        return pos;
                    }
                    start = pos;
                    visited = false;
                    inner = true;
                    break;

                case '<':
                    name = signature.substring(start, pos - 1);
                    if (inner) {
                        v.visitInnerClassType(name);
                    } else {
                        v.visitClassType(name);
                    }
                    visited = true;
                    top: for (;;) {
                        switch (c = signature.charAt(pos)) {
                        case '>':
                            break top;
                        case '*':
                            ++pos;
                            v.visitTypeArgument();
                            break;
                        case '+':
                        case '-':
                            pos = parseType(signature, pos + 1,
                                    v.visitTypeArgument(c));
                            break;
                        default:
                            pos = parseType(signature, pos,
                                    v.visitTypeArgument('='));
                            break;
                        }
                    }
                }
            }
        }
    }
}