/* ====================================================================
* Tea - Copyright (c) 1997-2000 Walt Disney Internet Group
* ====================================================================
* The Tea Software License, Version 1.1
*
* Copyright (c) 2000 Walt Disney Internet Group. 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. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Walt Disney Internet Group (http://opensource.go.com/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact opensource@dig.com.
*
* 5. Products derived from this software may not be called "Tea",
* "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet",
* "Kettle", "Trove" or "BeanDoc" appear in their name, without prior
* written permission of the Walt Disney Internet Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 WALT DISNEY INTERNET GROUP OR ITS
* 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.
* ====================================================================
*
* For more information about Tea, please see http://opensource.go.com/.
*/
package com.go.tea.compiler;
import java.lang.reflect.Method;
/******************************************************************************
* This class finds methods that best fit a given description. The compiler
* will then bind to one of those methods.
*
* @author Brian S O'Neill
* @version
* <!--$$Revision:--> 14 <!-- $-->, <!--$$JustDate:--> 9/07/00 <!-- $-->
*/
public class MethodMatcher {
/**
* The best result candidates are stored in the Method array passed in.
* The int returned indicates the number of candidates in the array. Zero
* is returned if there is no possible match.
*/
public static int match(Method[] methods, String name, Type[] params) {
int paramCount = params.length;
int matchCount = methods.length;
Method m;
int[] costs = new int[matchCount];
// Filter the available methods down to a smaller set, tossing
// out candidates that could not possibly match because the name
// differs, and the number of parameters differ. Also eliminate
// ones in which the parameter types are not compatible at all
// because no known conversion could be applied.
int lowestTotalCost = Integer.MAX_VALUE;
int length = matchCount;
matchCount = 0;
for (int i=0; i < length; i++) {
m = methods[i];
if (name == null || m.getName().equals(name)) {
Class[] methodParams = m.getParameterTypes();
if (methodParams.length == paramCount) {
int total = 0;
int j;
for (j=0; j<paramCount; j++) {
int cost = new Type(methodParams[j])
.convertableFrom(params[j]);
if (cost < 0) {
break;
}
else {
total += cost;
}
}
if (j == paramCount) {
costs[matchCount] = total;
methods[matchCount++] = m;
if (total < lowestTotalCost) {
lowestTotalCost = total;
}
}
}
}
}
if (matchCount <= 1) {
return matchCount;
}
// Filter out those that have a cost higher than lowestTotalCost.
length = matchCount;
matchCount = 0;
for (int i=0; i < length; i++) {
if (costs[i] <= lowestTotalCost) {
costs[matchCount] = costs[i];
methods[matchCount++] = methods[i];
}
}
if (matchCount <= 1) {
return matchCount;
}
// Filter further by matching parameters with the shortest distance
// in the hierarchy.
for (int j=0; j<paramCount; j++) {
Class lastMatch = null;
Method bestFit = null;
length = matchCount;
matchCount = 0;
for (int i=0; i < length; i++) {
m = methods[i];
if (bestFit == null) {
bestFit = m;
}
Class methodParam = m.getParameterTypes()[j];
Class param = params[j].getNaturalClass();
if (methodParam.isAssignableFrom(param)) {
if (lastMatch == null ||
lastMatch.isAssignableFrom(methodParam)) {
bestFit = m;
lastMatch = methodParam;
}
}
}
methods[matchCount++] = bestFit;
}
return matchCount;
}
/**
* Test program.
*/
/*
public static void main(String[] arg) throws Exception {
new Tester().test();
}
private static class Tester {
public Tester() {
}
public void test() {
Type t1 = new Type(boolean.class);
Type t2 = new Type(int.class);
Type t3 = new Type(float.class);
Type t4 = new Type(double.class);
Type t5 = new Type(Boolean.class);
Type t6 = new Type(Integer.class);
Type t7 = new Type(Float.class);
Type t8 = new Type(Double.class);
test("test", new Type[] {});
test("test", new Type[] {t1});
test("test", new Type[] {t2});
test("test", new Type[] {t3});
test("test", new Type[] {t4});
test("test", new Type[] {t5});
test("test", new Type[] {t6});
test("test", new Type[] {t7});
test("test", new Type[] {t8});
test("test2", new Type[] {t1});
test("test2", new Type[] {t2});
test("test2", new Type[] {t3});
test("test2", new Type[] {t4});
test("test2", new Type[] {t5});
test("test2", new Type[] {t6});
test("test2", new Type[] {t7});
test("test2", new Type[] {t8});
test("test3", new Type[] {t1});
test("test3", new Type[] {t2});
test("test3", new Type[] {t3});
test("test3", new Type[] {t4});
test("test3", new Type[] {t5});
test("test3", new Type[] {t6});
test("test3", new Type[] {t7});
test("test3", new Type[] {t8});
test("test4", new Type[] {t1});
test("test4", new Type[] {t2});
test("test4", new Type[] {t3});
test("test4", new Type[] {t4});
test("test4", new Type[] {t5});
test("test4", new Type[] {t6});
test("test4", new Type[] {t7});
test("test4", new Type[] {t8});
test("test5", new Type[] {t1});
test("test5", new Type[] {t2});
test("test5", new Type[] {t3});
test("test5", new Type[] {t4});
test("test5", new Type[] {t5});
test("test5", new Type[] {t6});
test("test5", new Type[] {t7});
test("test5", new Type[] {t8});
test("test6", new Type[] {t1});
test("test6", new Type[] {t2});
test("test6", new Type[] {t3});
test("test6", new Type[] {t4});
test("test6", new Type[] {t5});
test("test6", new Type[] {t6});
test("test6", new Type[] {t7});
test("test6", new Type[] {t8});
test("test7", new Type[] {t2, t6});
test("test7", new Type[] {t6, t2});
test("test7", new Type[] {t2, t2});
test("test7", new Type[] {t6, t6});
// Should only produce the method that accepts B
test("test8", new Type[] {new Type(C.class)});
}
private void test(String name, Type[] params) {
Method[] methods = this.getClass().getMethods();
int count = MethodMatcher.match(methods, name, params);
dump(methods, count);
}
private void dump(Method[] methods, int count) {
for (int i=0; i<count; i++) {
System.out.println(methods[i]);
}
System.out.println();
}
public void test(boolean i) {}
public void test(char i) {}
public void test(byte i) {}
public void test(short i) {}
public void test(int i) {}
public void test(float i) {}
public void test(long i) {}
public void test(double i) {}
public void test(Boolean i) {}
public void test(Character i) {}
public void test(Byte i) {}
public void test(Short i) {}
public void test(Integer i) {}
public void test(Float i) {}
public void test(Long i) {}
public void test(Double i) {}
public void test(Number i) {}
public void test(Object i) {}
public void test(String i) {}
public void test2(boolean i) {}
public void test2(char i) {}
public void test2(byte i) {}
public void test2(short i) {}
public void test2(int i) {}
public void test2(float i) {}
public void test2(long i) {}
public void test2(double i) {}
public void test3(Boolean i) {}
public void test3(Character i) {}
public void test3(Byte i) {}
public void test3(Short i) {}
public void test3(Integer i) {}
public void test3(Float i) {}
public void test3(Long i) {}
public void test3(Double i) {}
public void test3(Number i) {}
public void test4(Object i) {}
public void test4(String i) {}
public void test5(int i) {}
public void test5(String i) {}
public void test6(Number i) {}
public void test6(Integer i) {}
public void test6(String i) {}
public void test7(int i, Integer I) {}
public void test7(Integer I, int i) {}
private class A {}
private class B extends A {}
private class C extends B {}
public void test8(A a) {}
public void test8(B b) {}
}
*/
}
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