Scala example source code file (JType.java)

This example Scala source code file (JType.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

boolean, byte, byte, char, illegalargumentexception, illegalargumentexception, int, io, jtype, jtype, short, string, string, unknown, unsupportedoperationexception, util

The Scala JType.java source code

/* FJBG -- Fast Java Bytecode Generator
 * Copyright 2002-2011 LAMP/EPFL
 * @author  Michel Schinz
 */

package ch.epfl.lamp.fjbg;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;

/**
 * Representation of Java types.
 *
 * @version 1.0
 * @author Michel Schinz
 */

abstract public class JType {
    abstract public int getSize();
    abstract public String getSignature();
    abstract public int getTag();
    abstract public String toString();
    abstract public boolean isCompatibleWith(JType other);

    public boolean isValueType() { return false; }
    public boolean isObjectType() { return false; }
    public boolean isArrayType() { return false; }
    public boolean isReferenceType() { return false; }

    // Tags for types. Taken from BCEL.
    public static final int T_BOOLEAN = 4;
    public static final int T_CHAR    = 5;
    public static final int T_FLOAT   = 6;
    public static final int T_DOUBLE  = 7;
    public static final int T_BYTE    = 8;
    public static final int T_SHORT   = 9;
    public static final int T_INT     = 10;
    public static final int T_LONG    = 11;
    public static final int T_VOID    = 12; // Non-standard
    public static final int T_ARRAY   = 13;
    public static final int T_OBJECT  = 14;
    public static final int T_UNKNOWN = 15;
    public static final int T_ADDRESS = 16;

    public static final int T_REFERENCE = 17; // type compatible with references

    public static final JType[] EMPTY_ARRAY = new JType[0];

    protected static JType parseSig(StringReader s) throws IOException {
        int nextChar = s.read();
        if (nextChar == -1) throw new IllegalArgumentException();

        switch ((char)nextChar) {
        case 'V' : return VOID;
        case 'Z' : return BOOLEAN;
        case 'B' : return BYTE;
        case 'C' : return CHAR;
        case 'S' : return SHORT;
        case 'I' : return INT;
        case 'F' : return FLOAT;
        case 'J' : return LONG;
        case 'D' : return DOUBLE;
        case 'L': {
            StringBuffer className = new StringBuffer();
            for (;;) {
                nextChar = s.read();
                if (nextChar == -1 || nextChar == ';') break;
                className.append(nextChar == '/' ? ':' : ((char)nextChar));
            }
            if (nextChar != ';') throw new IllegalArgumentException();
            return new JObjectType(className.toString());
        }
        case '[': {
            JType elemType = parseSig(s);
            return new JArrayType(elemType);
        }
        case '(': {
            ArrayList argTps = new ArrayList();
            for (;;) {
                s.mark(1);
                nextChar = s.read();
                if (nextChar == -1 || nextChar == ')') break;
                s.reset();
                argTps.add(parseSig(s));
            }
            if (nextChar != ')') throw new IllegalArgumentException("a");
            JType[] argTpsA = (JType[])argTps.toArray(new JType[argTps.size()]);
            JType returnType = parseSig(s);
            return new JMethodType(returnType, argTpsA);
        }
        default:
            throw new IllegalArgumentException();
        }
    }

    /**
     * A signature is a string representing the generic type of a field or
     * method, or generic type information for a class declaration.
     * See section 4.4.4 of the JVM specification.
     */
    public static JType parseSignature(String signature) {
        try {
            StringReader sigReader = new StringReader(signature);
            JType parsed = parseSig(sigReader);
            if (sigReader.read() != -1)
                throw new IllegalArgumentException();
            return parsed;
        } catch (IllegalArgumentException e) {
            throw new IllegalArgumentException("invalid signature " + signature);
        } catch (IOException e) {
            throw new Error(e);
        }
    }

    public static int getTotalSize(JType[] types) {
        int size = 0;
        for (int i = 0; i < types.length; ++i)
            size += types[i].getSize();
        return size;
    }

    protected JType() {}

    public static JType VOID = new JType() {
        public int getSize() { return 0; }
        public String getSignature() { return "V"; }
        public int getTag() { return T_VOID; }
        public String toString() { return "void"; }
        public boolean isCompatibleWith(JType other) {
            throw new UnsupportedOperationException("type VOID is no real "
                                                    + "data type therefore "
                                                    + "cannot be assigned to "
                                                    + other.toString());
        }
    };

    public static JType BOOLEAN = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "Z"; }
        public int getTag() { return T_BOOLEAN; }
        public String toString() { return "boolean"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == BOOLEAN
                || other == INT
                || other == BYTE
                || other == CHAR
                || other == SHORT;
        }
    };

    public static JType BYTE = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "B"; }
        public int getTag() { return T_BYTE; }
        public String toString() { return "byte"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == BOOLEAN
                || other == INT
                || other == BYTE
                || other == CHAR
                || other == SHORT;
        }
    };

    public static JType CHAR = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "C"; }
        public int getTag() { return T_CHAR; }
        public String toString() { return "char"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == BOOLEAN
                || other == INT
                || other == BYTE
                || other == CHAR
                || other == SHORT;
        }
    };

    public static JType SHORT = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "S"; }
        public int getTag() { return T_SHORT; }
        public String toString() { return "short"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == BOOLEAN
                || other == INT
                || other == BYTE
                || other == CHAR
                || other == SHORT;
        }
    };

    public static JType INT = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "I"; }
        public int getTag() { return T_INT; }
        public String toString() { return "int"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == BOOLEAN
                || other == INT
                || other == BYTE
                || other == CHAR
                || other == SHORT;
        }
    };

    public static JType FLOAT = new JType() {
        public int getSize() { return 1; }
        public String getSignature() { return "F"; }
        public int getTag() { return T_FLOAT; }
        public String toString() { return "float"; }
        public boolean isValueType() { return true; }
        public boolean isCompatibleWith(JType other) {
            return other == FLOAT;
        }
    };

    public static JType LONG = new JType() {
            public int getSize() { return 2; }
            public String getSignature() { return "J"; }
            public int getTag() { return T_LONG; }
            public String toString() { return "long"; }
            public boolean isValueType() { return true; }
            public boolean isCompatibleWith(JType other) {
                return other == LONG;
            }
        };

    public static JType DOUBLE = new JType() {
            public int getSize() { return 2; }
            public String getSignature() { return "D"; }
            public int getTag() { return T_DOUBLE; }
            public String toString() { return "double"; }
            public boolean isValueType() { return true; }
            public boolean isCompatibleWith(JType other) {
                return other == DOUBLE;
            }
        };

    public static JType REFERENCE = new JType() {
            public int getSize() { return 1; }
            public String getSignature() {
                throw new UnsupportedOperationException("type REFERENCE is no real "
                                                        + "data type and therefore "
                                                        + "has no signature");
            }
            public int getTag() { return T_REFERENCE; }
            public String toString() { return "<reference>"; }
            public boolean isCompatibleWith(JType other) {
                throw new UnsupportedOperationException("type REFERENCE is no real "
                                                        + "data type and therefore "
                                                        + "cannot be assigned to "
                                                        + other.toString());
            }
        };

    public static JType ADDRESS = new JType() {
        public int getSize() { return 1; }
        public String getSignature() {
            throw new UnsupportedOperationException("type ADDRESS is no usable "
                                                    + "data type and therefore "
                                                    + "has no signature");
        }
        public int getTag() { return T_ADDRESS; }
        public String toString() { return "<address>"; }
        public boolean isCompatibleWith(JType other) {
            return other == ADDRESS;
        }
    };

    public static JType UNKNOWN = new JType() {
        public int getSize() {
            throw new UnsupportedOperationException("type UNKNOWN is no real "
                                                    + "data type and therefore "
                                                    + "has no size");
        }
        public String getSignature() {
            throw new UnsupportedOperationException("type UNKNOWN is no real "
                                                    + "data type and therefore "
                                                    + "has no signature");
        }
        public int getTag() { return T_UNKNOWN; }
        public String toString() { return "<unknown>"; }
        public boolean isCompatibleWith(JType other) {
            throw new UnsupportedOperationException("type UNKNOWN is no real "
                                                    + "data type and therefore "
                                                    + "cannot be assigned to "
                                                    + other.toString());
        }
    };

    protected static String tagToString(int tag) {
        switch (tag) {
        case T_BOOLEAN : return "boolean";
        case T_CHAR    : return "char";
        case T_FLOAT   : return "float";
        case T_DOUBLE  : return "double";
        case T_BYTE    : return "byte";
        case T_SHORT   : return "short";
        case T_INT     : return "int";
        case T_LONG    : return "long";
        case T_VOID    : return "void"; // Non-standard
        case T_ARRAY   : return "[]";
        case T_OBJECT  : return "Object";
        case T_UNKNOWN : return "<unknown>";
        case T_ADDRESS : return "<address>";
        default:         return String.valueOf(tag);
        }
    }
}