/*
* @(#)DeclarationFilter.java 1.2 04/07/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package com.sun.mirror.util;
import java.util.ArrayList;
import java.util.Collection;
import com.sun.mirror.declaration.Declaration;
import com.sun.mirror.declaration.Modifier;
import static com.sun.mirror.declaration.Modifier.*;
/**
* A filter for selecting just the items of interest
* from a collection of declarations.
* The filter is said to <i>select</i> or to <i>match</i> those declarations.
* Filters can be created in several ways:
* by the static methods described below,
* by negating or composing existing filters,
* or by subclasses that implement arbitrary matching rules.
*
* <p> A subclass can create an arbitrary filter simply by implementing
* the {@link #matches(Declaration)} method.
*
* <p> Examples.
* <p> Selecting the <tt>public</tt> declarations from a collection:
* <blockquote><pre>
* result = FILTER_PUBLIC.filter(decls); </pre></blockquote>
* Selecting class declarations (including enums):
* <blockquote><pre>
* classFilter = DeclarationFilter.getFilter(ClassDeclaration.class);
* result = classFilter.filter(decls); </pre></blockquote>
* Selecting class declarations but excluding enums:
* <blockquote><pre>
* enumFilter = DeclarationFilter.getFilter(EnumDeclaration.class);
* compoundFilter = classFilter.and(enumFilter.not());
* result = compoundFilter.filter(decls); </pre></blockquote>
* Selecting declarations named "Bob":
* <blockquote><pre>
* nameFilter = new DeclarationFilter() {
* public boolean matches(Declaration d) {
* return d.getSimpleName().equals("Bob");
* }
* };
* result = nameFilter.filter(decls); </pre></blockquote>
*
* @author Joseph D. Darcy
* @author Scott Seligman
* @version 1.2 04/07/19
* @since 1.5
*/
public class DeclarationFilter {
// Predefined filters for convenience.
/**
* A filter that selects only <tt>public</tt> declarations.
*/
public static final DeclarationFilter FILTER_PUBLIC =
new AccessFilter(PUBLIC);
/**
* A filter that selects only <tt>protected</tt> declarations.
*/
public static final DeclarationFilter FILTER_PROTECTED =
new AccessFilter(PROTECTED);
/**
* A filter that selects only <tt>public</tt> or <tt>protected</tt>
* declarations.
*/
public static final DeclarationFilter FILTER_PUBLIC_OR_PROTECTED =
new AccessFilter(PUBLIC, PROTECTED);
/**
* A filter that selects only package-private (<i>default</i>)
* declarations.
*/
public static final DeclarationFilter FILTER_PACKAGE =
new AccessFilter();
/**
* A filter that selects only <tt>private</tt> declarations.
*/
public static final DeclarationFilter FILTER_PRIVATE =
new AccessFilter(PRIVATE);
/**
* Constructs an identity filter: one that selects all declarations.
*/
public DeclarationFilter() {
}
// Methods to create a filter.
/**
* Returns a filter that selects declarations containing all of a
* collection of modifiers.
*
* @param mods the modifiers to match (non-null)
* @return a filter that matches declarations containing <tt>mods</tt>
*/
public static DeclarationFilter getFilter(
final Collection<Modifier> mods) {
return new DeclarationFilter() {
public boolean matches(Declaration d) {
return d.getModifiers().containsAll(mods);
}
};
}
/**
* Returns a filter that selects declarations of a particular kind.
* For example, there may be a filter that selects only class
* declarations, or only fields.
* The filter will select declarations of the specified kind,
* and also any subtypes of that kind; for example, a field filter
* will also select enum constants.
*
* @param kind the kind of declarations to select
* @return a filter that selects declarations of a particular kind
*/
public static DeclarationFilter getFilter(
final Class<? extends Declaration> kind) {
return new DeclarationFilter() {
public boolean matches(Declaration d) {
return kind.isInstance(d);
}
};
}
/**
* Returns a filter that selects those declarations selected
* by both this filter and another.
*
* @param f filter to be composed with this one
* @return a filter that selects those declarations selected by
* both this filter and another
*/
public DeclarationFilter and(DeclarationFilter f) {
final DeclarationFilter f1 = this;
final DeclarationFilter f2 = f;
return new DeclarationFilter() {
public boolean matches(Declaration d) {
return f1.matches(d) && f2.matches(d);
}
};
}
/**
* Returns a filter that selects those declarations selected
* by either this filter or another.
*
* @param f filter to be composed with this one
* @return a filter that selects those declarations selected by
* either this filter or another
*/
public DeclarationFilter or(DeclarationFilter f) {
final DeclarationFilter f1 = this;
final DeclarationFilter f2 = f;
return new DeclarationFilter() {
public boolean matches(Declaration d) {
return f1.matches(d) || f2.matches(d);
}
};
}
/**
* Returns a filter that selects those declarations not selected
* by this filter.
*
* @return a filter that selects those declarations not selected
* by this filter
*/
public DeclarationFilter not() {
return new DeclarationFilter() {
public boolean matches(Declaration d) {
return !DeclarationFilter.this.matches(d);
}
};
}
// Methods to apply a filter.
/**
* Tests whether this filter matches a given declaration.
* The default implementation always returns <tt>true</tt>;
* subclasses should override this.
*
* @param decl the declaration to match
* @return <tt>true</tt> if this filter matches the given declaration
*/
public boolean matches(Declaration decl) {
return true;
}
/**
* Returns the declarations matched by this filter.
* The result is a collection of the same type as the argument;
* the {@linkplain #filter(Collection, Class) two-parameter version}
* of <tt>filter</tt> offers control over the result type.
*
* @param <D> type of the declarations being filtered
* @param decls declarations being filtered
* @return the declarations matched by this filter
*/
public <D extends Declaration> Collection<D> filter(Collection<D> decls) {
ArrayList<D> res = new ArrayList<D>(decls.size());
for (D d : decls) {
if (matches(d)) {
res.add(d);
}
}
return res;
}
/**
* Returns the declarations matched by this filter, with the result
* being restricted to declarations of a given kind.
* Similar to the simpler
* {@linkplain #filter(Collection) single-parameter version}
* of <tt>filter</tt>, but the result type is specified explicitly.
*
* @param <D> type of the declarations being returned
* @param decls declarations being filtered
* @param resType type of the declarations being returned --
* the reflective view of <tt>D</tt>
* @return the declarations matched by this filter, restricted to those
* of the specified type
*/
public <D extends Declaration> Collection<D>
filter(Collection<? extends Declaration> decls, Class<D> resType) {
ArrayList<D> res = new ArrayList<D>(decls.size());
for (Declaration d : decls) {
if (resType.isInstance(d) && matches(d)) {
res.add(resType.cast(d));
}
}
return res;
}
/*
* A filter based on access modifiers.
*/
private static class AccessFilter extends DeclarationFilter {
// The first access modifier to filter on, or null if we're looking
// for declarations with no access modifiers.
private Modifier mod1 = null;
// The second access modifier to filter on, or null if none.
private Modifier mod2 = null;
// Returns a filter that matches declarations with no access
// modifiers.
AccessFilter() {
}
// Returns a filter that matches m.
AccessFilter(Modifier m) {
mod1 = m;
}
// Returns a filter that matches either m1 or m2.
AccessFilter(Modifier m1, Modifier m2) {
mod1 = m1;
mod2 = m2;
}
public boolean matches(Declaration d) {
Collection<Modifier> mods = d.getModifiers();
if (mod1 == null) { // looking for package private
return !(mods.contains(PUBLIC) ||
mods.contains(PROTECTED) ||
mods.contains(PRIVATE));
}
return mods.contains(mod1) &&
(mod2 == null || mods.contains(mod2));
}
}
}
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