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	/*
	* Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.tools.java;

	import java.util.*;

	/**
	* The MethodSet structure is used to store methods for a class.
	* It maintains the invariant that it never stores two methods
	* with the same signature. MethodSets are able to lookup
	* all methods with a given name and the unique method with a given
	* signature (name, args).
	*
	* WARNING: The contents of this source file are not part of any
	* supported API. Code that depends on them does so at its own risk:
	* they are subject to change or removal without notice.
	*/

	public
	class MethodSet {

	/**
	* A Map containing Lists of MemberDefinitions. The Lists
	* contain methods which share the same name.
	*/
	private final Map lookupMap;

	/**
	* The number of methods stored in the MethodSet.
	*/
	private int count;

	/**
	* Is this MethodSet currently frozen? See freeze() for more details.
	*/
	private boolean frozen;

	/**
	* Creates a brand new MethodSet
	*/
	public MethodSet() {
	frozen = false;
	lookupMap = new HashMap();
	count = 0;
	}

	/**
	* Returns the number of distinct methods stored in the MethodSet.
	*/
	public int size() {
	return count;
	}

	/**
	* Adds `method' to the MethodSet. No method of the same signature
	* should be already defined.
	*/
	public void add(MemberDefinition method) {
	// Check for late additions.
	if (frozen) {
	throw new CompilerError("add()");
	}

	// todo: Check for method??

	Identifier name = method.getName();

	// Get a List containing all methods of this name.
	List methodList = (List) lookupMap.get(name);

	if (methodList == null) {
	// There is no method with this name already.
	// Create a List, and insert it into the hash.
	methodList = new ArrayList();
	lookupMap.put(name, methodList);
	}

	// Make sure that no method with the same signature has already
	// been added to the MethodSet.
	int size = methodList.size();
	for (int i = 0; i < size; i++) {
	if (((MemberDefinition) methodList.get(i))
	.getType().equalArguments(method.getType())) {
	throw new CompilerError("duplicate addition");
	}
	}

	// We add the method to the appropriate list.
	methodList.add(method);
	count++;
	}

	/**
	* Adds `method' to the MethodSet, replacing any previous definition
	* with the same signature.
	*/
	public void replace(MemberDefinition method) {
	// Check for late additions.
	if (frozen) {
	throw new CompilerError("replace()");
	}

	// todo: Check for method??

	Identifier name = method.getName();

	// Get a List containing all methods of this name.
	List methodList = (List) lookupMap.get(name);

	if (methodList == null) {
	// There is no method with this name already.
	// Create a List, and insert it into the hash.
	methodList = new ArrayList();
	lookupMap.put(name, methodList);
	}

	// Replace the element which has the same signature as
	// `method'.
	int size = methodList.size();
	for (int i = 0; i < size; i++) {
	if (((MemberDefinition) methodList.get(i))
	.getType().equalArguments(method.getType())) {
	methodList.set(i, method);
	return;
	}
	}

	// We add the method to the appropriate list.
	methodList.add(method);
	count++;
	}

	/**
	* If the MethodSet contains a method with the same signature
	* then lookup() returns it. Otherwise, this method returns null.
	*/
	public MemberDefinition lookupSig(Identifier name, Type type) {
	// Go through all methods of the same name and see if any
	// have the right signature.
	Iterator matches = lookupName(name);
	MemberDefinition candidate;

	while (matches.hasNext()) {
	candidate = (MemberDefinition) matches.next();
	if (candidate.getType().equalArguments(type)) {
	return candidate;
	}
	}

	// No match.
	return null;
	}

	/**
	* Returns an Iterator of all methods contained in the
	* MethodSet which have a given name.
	*/
	public Iterator lookupName(Identifier name) {
	// Find the List containing all methods of this name, and
	// return that List's Iterator.
	List methodList = (List) lookupMap.get(name);
	if (methodList == null) {
	// If there is no method of this name, return a bogus, empty
	// Iterator.
	return Collections.emptyIterator();
	}
	return methodList.iterator();
	}

	/**
	* Returns an Iterator of all methods in the MethodSet
	*/
	public Iterator iterator() {

	//----------------------------------------------------------
	// The inner class MethodIterator is used to create our
	// Iterator of all methods in the MethodSet.
	class MethodIterator implements Iterator {
	Iterator hashIter = lookupMap.values().iterator();
	Iterator listIter = Collections.emptyIterator();

	public boolean hasNext() {
	if (listIter.hasNext()) {
	return true;
	} else {
	if (hashIter.hasNext()) {
	listIter = ((List) hashIter.next())
	.iterator();

	// The following should be always true.
	if (listIter.hasNext()) {
	return true;
	} else {
	throw new
	CompilerError("iterator() in MethodSet");
	}
	}
	}

	// We've run out of Lists.
	return false;
	}

	public Object next() {
	return listIter.next();
	}

	public void remove() {
	throw new UnsupportedOperationException();
	}
	}
	// end MethodIterator
	//----------------------------------------------------------

	// A one-liner.
	return new MethodIterator();
	}

	/**
	* After freeze() is called, the MethodSet becomes (mostly)
	* immutable. Any calls to add() or addMeet() lead to
	* CompilerErrors. Note that the entries themselves are still
	* (unfortunately) open for mischievous and wanton modification.
	*/
	public void freeze() {
	frozen = true;
	}

	/**
	* Tells whether freeze() has been called on this MethodSet.
	*/
	public boolean isFrozen() {
	return frozen;
	}

	/**
	* Returns a (big) string representation of this MethodSet
	*/
	public String toString() {
	int len = size();
	StringBuffer buf = new StringBuffer();
	Iterator all = iterator();
	buf.append("{");

	while (all.hasNext()) {
	buf.append(all.next().toString());
	len--;
	if (len > 0) {
	buf.append(", ");
	}
	}
	buf.append("}");
	return buf.toString();
	}
	}

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