/**
* Copyright (C) 2014-2017 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.helger.css.decl.visit;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import com.helger.commons.ValueEnforcer;
import com.helger.commons.annotation.PresentForCodeCoverage;
import com.helger.css.decl.CSSDeclaration;
import com.helger.css.decl.CSSFontFaceRule;
import com.helger.css.decl.CSSImportRule;
import com.helger.css.decl.CSSKeyframesBlock;
import com.helger.css.decl.CSSKeyframesRule;
import com.helger.css.decl.CSSMediaRule;
import com.helger.css.decl.CSSNamespaceRule;
import com.helger.css.decl.CSSPageMarginBlock;
import com.helger.css.decl.CSSPageRule;
import com.helger.css.decl.CSSSelector;
import com.helger.css.decl.CSSStyleRule;
import com.helger.css.decl.CSSSupportsRule;
import com.helger.css.decl.CSSUnknownRule;
import com.helger.css.decl.CSSViewportRule;
import com.helger.css.decl.CascadingStyleSheet;
import com.helger.css.decl.ICSSPageRuleMember;
import com.helger.css.decl.ICSSTopLevelRule;
import com.helger.css.decl.IHasCSSDeclarations;
/**
* This class is used to walk a CSS domain object and call the respective
* {@link ICSSVisitor} and {@link ICSSUrlVisitor} interface methods. Method
* {@link #visitCSS(CascadingStyleSheet, ICSSVisitor)} is usually the entry
* point to iterate over the whole content of a parsed CSS.
*
* @author Philip Helger
*/
@Immutable
public final class CSSVisitor
{
@PresentForCodeCoverage
private static final CSSVisitor s_aInstance = new CSSVisitor ();
private CSSVisitor ()
{}
/**
* Visit all elements of a single import rule.
*
* @param aImportRule
* The import rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitImportRule (@Nonnull final CSSImportRule aImportRule, @Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onImport (aImportRule);
}
/**
* Visit all elements of a single namespace rule.
*
* @param aNamespaceRule
* The namespace rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitNamespaceRule (@Nonnull final CSSNamespaceRule aNamespaceRule,
@Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onNamespace (aNamespaceRule);
}
/**
* Visit all declarations contained in the passed declaration container.
*
* @param aHasDeclarations
* The declarations to be visited. May not be <code>null</code>.
* @param aVisitor
* The visitor to be invoked on each declaration. May not be
* <code>null</code>.
*/
public static void visitAllDeclarations (@Nonnull final IHasCSSDeclarations <?> aHasDeclarations,
@Nonnull final ICSSVisitor aVisitor)
{
// for all declarations
for (final CSSDeclaration aDeclaration : aHasDeclarations.getAllDeclarations ())
aVisitor.onDeclaration (aDeclaration);
}
/**
* Visit all elements of a single style rule.
*
* @param aStyleRule
* The style rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitStyleRule (@Nonnull final CSSStyleRule aStyleRule, @Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginStyleRule (aStyleRule);
try
{
// for all selectors
for (final CSSSelector aSelector : aStyleRule.getAllSelectors ())
aVisitor.onStyleRuleSelector (aSelector);
// for all declarations
visitAllDeclarations (aStyleRule, aVisitor);
}
finally
{
aVisitor.onEndStyleRule (aStyleRule);
}
}
/**
* Visit all elements of a single page rule.
*
* @param aPageRule
* The page rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitPageRule (@Nonnull final CSSPageRule aPageRule, @Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginPageRule (aPageRule);
try
{
// for all declarations
for (final ICSSPageRuleMember aMember : aPageRule.getAllMembers ())
if (aMember instanceof CSSDeclaration)
aVisitor.onDeclaration ((CSSDeclaration) aMember);
else
{
final CSSPageMarginBlock aPageMarginBlock = (CSSPageMarginBlock) aMember;
aVisitor.onBeginPageMarginBlock (aPageMarginBlock);
try
{
// for all declarations
visitAllDeclarations (aPageMarginBlock, aVisitor);
}
finally
{
aVisitor.onEndPageMarginBlock (aPageMarginBlock);
}
}
}
finally
{
aVisitor.onEndPageRule (aPageRule);
}
}
/**
* Visit all elements of a single font-face rule.
*
* @param aFontFaceRule
* The font-face rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitFontFaceRule (@Nonnull final CSSFontFaceRule aFontFaceRule,
@Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginFontFaceRule (aFontFaceRule);
try
{
// for all declarations
visitAllDeclarations (aFontFaceRule, aVisitor);
}
finally
{
aVisitor.onEndFontFaceRule (aFontFaceRule);
}
}
/**
* Visit all elements of a single media rule.
*
* @param aMediaRule
* The media rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitMediaRule (@Nonnull final CSSMediaRule aMediaRule, @Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginMediaRule (aMediaRule);
try
{
// for all nested rules
for (final ICSSTopLevelRule aRule : aMediaRule.getAllRules ())
visitTopLevelRule (aRule, aVisitor);
}
finally
{
aVisitor.onEndMediaRule (aMediaRule);
}
}
/**
* Visit all elements of a single keyframes rule.
*
* @param aKeyframesRule
* The keyframes rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitKeyframesRule (@Nonnull final CSSKeyframesRule aKeyframesRule,
@Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginKeyframesRule (aKeyframesRule);
try
{
// for all keyframes blocks
for (final CSSKeyframesBlock aBlock : aKeyframesRule.getAllBlocks ())
{
aVisitor.onBeginKeyframesBlock (aBlock);
try
{
// for all declarations
visitAllDeclarations (aBlock, aVisitor);
}
finally
{
aVisitor.onEndKeyframesBlock (aBlock);
}
}
}
finally
{
aVisitor.onEndKeyframesRule (aKeyframesRule);
}
}
/**
* Visit all elements of a single viewport rule.
*
* @param aViewportRule
* The viewport rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitViewportRule (@Nonnull final CSSViewportRule aViewportRule,
@Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginViewportRule (aViewportRule);
try
{
// for all declarations
visitAllDeclarations (aViewportRule, aVisitor);
}
finally
{
aVisitor.onEndViewportRule (aViewportRule);
}
}
/**
* Visit all elements of a single supports rule.
*
* @param aSupportsRule
* The supports rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitSupportsRule (@Nonnull final CSSSupportsRule aSupportsRule,
@Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onBeginSupportsRule (aSupportsRule);
try
{
// for all nested rules
for (final ICSSTopLevelRule aRule : aSupportsRule.getAllRules ())
visitTopLevelRule (aRule, aVisitor);
}
finally
{
aVisitor.onEndSupportsRule (aSupportsRule);
}
}
/**
* Visit all elements of a single unknown @ rule.
*
* @param aUnknownRule
* The unknown rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitUnknownRule (@Nonnull final CSSUnknownRule aUnknownRule, @Nonnull final ICSSVisitor aVisitor)
{
aVisitor.onUnknownRule (aUnknownRule);
}
/**
* Visit all elements of a single top-level rule. This includes all rules
* except <code>@import</code> and <code>@namespace</code> rules.
*
* @param aTopLevelRule
* The top-level rule to visit. May not be <code>null</code>.
* @param aVisitor
* The visitor to use. May not be <code>null</code>.
*/
public static void visitTopLevelRule (@Nonnull final ICSSTopLevelRule aTopLevelRule,
@Nonnull final ICSSVisitor aVisitor)
{
if (aTopLevelRule instanceof CSSStyleRule)
{
visitStyleRule ((CSSStyleRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSPageRule)
{
visitPageRule ((CSSPageRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSFontFaceRule)
{
visitFontFaceRule ((CSSFontFaceRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSMediaRule)
{
visitMediaRule ((CSSMediaRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSKeyframesRule)
{
visitKeyframesRule ((CSSKeyframesRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSViewportRule)
{
visitViewportRule ((CSSViewportRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSSupportsRule)
{
visitSupportsRule ((CSSSupportsRule) aTopLevelRule, aVisitor);
}
else
if (aTopLevelRule instanceof CSSUnknownRule)
{
visitUnknownRule ((CSSUnknownRule) aTopLevelRule, aVisitor);
}
else
throw new IllegalStateException ("Top level rule " + aTopLevelRule + " is unsupported!");
}
/**
* Visit all CSS elements in the order of their declaration. import rules come
* first, namespace rules come next and all other top-level rules in the order
* of their declaration.
*
* @param aCSS
* The CSS to visit. May not be <code>null</code>.
* @param aVisitor
* The callback to be invoked for each element found. May not be
* <code>null</code>.
*/
public static void visitCSS (@Nonnull final CascadingStyleSheet aCSS, @Nonnull final ICSSVisitor aVisitor)
{
ValueEnforcer.notNull (aCSS, "CSS");
ValueEnforcer.notNull (aVisitor, "Visitor");
aVisitor.begin ();
try
{
// for all imports
for (final CSSImportRule aImportRule : aCSS.getAllImportRules ())
visitImportRule (aImportRule, aVisitor);
// for all namespaces
for (final CSSNamespaceRule aNamespaceRule : aCSS.getAllNamespaceRules ())
visitNamespaceRule (aNamespaceRule, aVisitor);
// for all other top level rules
for (final ICSSTopLevelRule aTopLevelRule : aCSS.getAllRules ())
visitTopLevelRule (aTopLevelRule, aVisitor);
}
finally
{
aVisitor.end ();
}
}
/**
* Visit all items that can contain URLs in CSS files. Therefore the special
* visitor class {@link CSSVisitorForUrl} is used.
*
* @param aCSS
* The CSS to visit. May not be <code>null</code>.
* @param aVisitor
* The callback to invoke for each found occurrence. May not be
* <code>null</code>.
* @see CSSVisitorForUrl
*/
public static void visitCSSUrl (@Nonnull final CascadingStyleSheet aCSS, @Nonnull final ICSSUrlVisitor aVisitor)
{
// Visit only the URLs of a CSS with a specific CSS visitor
visitCSS (aCSS, new CSSVisitorForUrl (aVisitor));
}
/**
* Visit all items that can contain URLs in CSS files. Therefore the special
* visitor class {@link CSSVisitorForUrl} is used.
*
* @param aCSS
* The CSS to visit. May not be <code>null</code>.
* @param aVisitor
* The callback to invoke for each found occurrence. May not be
* <code>null</code>.
*/
public static void visitAllDeclarationUrls (@Nonnull final IHasCSSDeclarations <?> aCSS,
@Nonnull final ICSSUrlVisitor aVisitor)
{
// Visit only the URLs of a CSS with a specific CSS visitor
visitAllDeclarations (aCSS, new CSSVisitorForUrl (aVisitor));
}
}