Java example source code file (Method.java)

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Java - Java tags/keywords

descriptors, hashmap, illegalargumentexception, map, method, object, override, string, stringbuffer, type, util

The Method.java Java 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 clojure.asm.commons;

import java.util.HashMap;
import java.util.Map;

import clojure.asm.Type;

/**
 * A named method descriptor.
 *
 * @author Juozas Baliuka
 * @author Chris Nokleberg
 * @author Eric Bruneton
 */
public class Method {

    /**
     * The method name.
     */
    private final String name;

    /**
     * The method descriptor.
     */
    private final String desc;

    /**
     * Maps primitive Java type names to their descriptors.
     */
    private static final Map<String, String> DESCRIPTORS;

    static {
        DESCRIPTORS = new HashMap<String, String>();
        DESCRIPTORS.put("void", "V");
        DESCRIPTORS.put("byte", "B");
        DESCRIPTORS.put("char", "C");
        DESCRIPTORS.put("double", "D");
        DESCRIPTORS.put("float", "F");
        DESCRIPTORS.put("int", "I");
        DESCRIPTORS.put("long", "J");
        DESCRIPTORS.put("short", "S");
        DESCRIPTORS.put("boolean", "Z");
    }

    /**
     * Creates a new {@link Method}.
     *
     * @param name
     *            the method's name.
     * @param desc
     *            the method's descriptor.
     */
    public Method(final String name, final String desc) {
        this.name = name;
        this.desc = desc;
    }

    /**
     * Creates a new {@link Method}.
     *
     * @param name
     *            the method's name.
     * @param returnType
     *            the method's return type.
     * @param argumentTypes
     *            the method's argument types.
     */
    public Method(final String name, final Type returnType,
            final Type[] argumentTypes) {
        this(name, Type.getMethodDescriptor(returnType, argumentTypes));
    }

    /**
     * Creates a new {@link Method}.
     *
     * @param m
     *            a java.lang.reflect method descriptor
     * @return a {@link Method} corresponding to the given Java method
     *         declaration.
     */
    public static Method getMethod(java.lang.reflect.Method m) {
        return new Method(m.getName(), Type.getMethodDescriptor(m));
    }

    /**
     * Creates a new {@link Method}.
     *
     * @param c
     *            a java.lang.reflect constructor descriptor
     * @return a {@link Method} corresponding to the given Java constructor
     *         declaration.
     */
    public static Method getMethod(java.lang.reflect.Constructor<?> c) {
        return new Method("<init>", Type.getConstructorDescriptor(c));
    }

    /**
     * Returns a {@link Method} corresponding to the given Java method
     * declaration.
     *
     * @param method
     *            a Java method declaration, without argument names, of the form
     *            "returnType name (argumentType1, ... argumentTypeN)", where
     *            the types are in plain Java (e.g. "int", "float",
     *            "java.util.List", ...). Classes of the java.lang package can
     *            be specified by their unqualified name; all other classes
     *            names must be fully qualified.
     * @return a {@link Method} corresponding to the given Java method
     *         declaration.
     * @throws IllegalArgumentException
     *             if <code>method could not get parsed.
     */
    public static Method getMethod(final String method)
            throws IllegalArgumentException {
        return getMethod(method, false);
    }

    /**
     * Returns a {@link Method} corresponding to the given Java method
     * declaration.
     *
     * @param method
     *            a Java method declaration, without argument names, of the form
     *            "returnType name (argumentType1, ... argumentTypeN)", where
     *            the types are in plain Java (e.g. "int", "float",
     *            "java.util.List", ...). Classes of the java.lang package may
     *            be specified by their unqualified name, depending on the
     *            defaultPackage argument; all other classes names must be fully
     *            qualified.
     * @param defaultPackage
     *            true if unqualified class names belong to the default package,
     *            or false if they correspond to java.lang classes. For instance
     *            "Object" means "Object" if this option is true, or
     *            "java.lang.Object" otherwise.
     * @return a {@link Method} corresponding to the given Java method
     *         declaration.
     * @throws IllegalArgumentException
     *             if <code>method could not get parsed.
     */
    public static Method getMethod(final String method,
            final boolean defaultPackage) throws IllegalArgumentException {
        int space = method.indexOf(' ');
        int start = method.indexOf('(', space) + 1;
        int end = method.indexOf(')', start);
        if (space == -1 || start == -1 || end == -1) {
            throw new IllegalArgumentException();
        }
        String returnType = method.substring(0, space);
        String methodName = method.substring(space + 1, start - 1).trim();
        StringBuffer sb = new StringBuffer();
        sb.append('(');
        int p;
        do {
            String s;
            p = method.indexOf(',', start);
            if (p == -1) {
                s = map(method.substring(start, end).trim(), defaultPackage);
            } else {
                s = map(method.substring(start, p).trim(), defaultPackage);
                start = p + 1;
            }
            sb.append(s);
        } while (p != -1);
        sb.append(')');
        sb.append(map(returnType, defaultPackage));
        return new Method(methodName, sb.toString());
    }

    private static String map(final String type, final boolean defaultPackage) {
        if ("".equals(type)) {
            return type;
        }

        StringBuffer sb = new StringBuffer();
        int index = 0;
        while ((index = type.indexOf("[]", index) + 1) > 0) {
            sb.append('[');
        }

        String t = type.substring(0, type.length() - sb.length() * 2);
        String desc = DESCRIPTORS.get(t);
        if (desc != null) {
            sb.append(desc);
        } else {
            sb.append('L');
            if (t.indexOf('.') < 0) {
                if (!defaultPackage) {
                    sb.append("java/lang/");
                }
                sb.append(t);
            } else {
                sb.append(t.replace('.', '/'));
            }
            sb.append(';');
        }
        return sb.toString();
    }

    /**
     * Returns the name of the method described by this object.
     *
     * @return the name of the method described by this object.
     */
    public String getName() {
        return name;
    }

    /**
     * Returns the descriptor of the method described by this object.
     *
     * @return the descriptor of the method described by this object.
     */
    public String getDescriptor() {
        return desc;
    }

    /**
     * Returns the return type of the method described by this object.
     *
     * @return the return type of the method described by this object.
     */
    public Type getReturnType() {
        return Type.getReturnType(desc);
    }

    /**
     * Returns the argument types of the method described by this object.
     *
     * @return the argument types of the method described by this object.
     */
    public Type[] getArgumentTypes() {
        return Type.getArgumentTypes(desc);
    }

    @Override
    public String toString() {
        return name + desc;
    }

    @Override
    public boolean equals(final Object o) {
        if (!(o instanceof Method)) {
            return false;
        }
        Method other = (Method) o;
        return name.equals(other.name) && desc.equals(other.desc);
    }

    @Override
    public int hashCode() {
        return name.hashCode() ^ desc.hashCode();
    }
}