/*
* Copyright 2008 Google Inc.
*
* 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.google.common.css.compiler.ast;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.collect.UnmodifiableIterator;
import com.google.common.css.SourceCodeLocation;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import javax.annotation.Nullable;
/**
* A CSS node that holds a value of some sort. This is the base class for all
* the nodes in the abstract syntax tree that have a value.
*
* TODO(oana): Maybe de-emphasize the value aspect, allow value to be null, and
* rename this as CssTermNode.
*
*/
public abstract class CssValueNode extends CssNode {
/** The value contained by the node. */
private String value;
/** Annotation to show whether this is a default value or not. */
private boolean isDefault;
/**
* Constructor of a node that contains a value.
*
* @param value
* @param sourceCodeLocation
*/
public CssValueNode(@Nullable String value,
@Nullable SourceCodeLocation sourceCodeLocation) {
super(sourceCodeLocation);
this.value = value;
this.isDefault = false;
}
/**
* Constructor of a node that contains a value.
*
* @param value
*/
public CssValueNode(String value) {
this(value, null);
}
/**
* Copy constructor.
*
* @param node
*/
public CssValueNode(CssValueNode node) {
this(node.getValue(), node.getSourceCodeLocation());
this.isDefault = node.getIsDefault();
}
@Override
public abstract CssValueNode deepCopy();
public String getValue() {
return this.value;
}
/**
* Subclasses should perform additional consistency checks. For example, a
* boolean expression node will not allow setting this as boolean expression
* trees are immutable.
*/
public void setValue(String value) {
Preconditions.checkNotNull(value);
this.value = value;
}
public void setIsDefault(boolean isDefault) {
this.isDefault = isDefault;
}
public boolean getIsDefault() {
return isDefault;
}
/**
* Visit just the leaves in the subtrees from the given roots.
*/
public static Iterable<CssValueNode> leaves(
final Collection<CssValueNode> roots) {
return new Iterable<CssValueNode>() {
public Iterator<CssValueNode> iterator() {
return new UnmodifiableIterator<CssValueNode>() {
LinkedList<CssValueNode> q;
{
q = Lists.newLinkedList();
q.addAll(roots);
}
List<CssValueNode> expand(CssValueNode n) {
if (n instanceof CssBooleanExpressionNode) {
CssBooleanExpressionNode b = (CssBooleanExpressionNode) n;
return ImmutableList.<CssValueNode>of(b.getLeft(), b.getRight());
} else if (n instanceof CssCompositeValueNode) {
CssCompositeValueNode c = (CssCompositeValueNode) n;
return c.getValues();
} else {
return ImmutableList.<CssValueNode>of(n);
}
}
void advance() {
CssValueNode unexpanded;
List<CssValueNode> expanded;
do {
unexpanded = q.remove();
expanded = expand(unexpanded);
q.addAll(0, expanded);
} while (expanded.size() != 1
|| !expanded.get(0).equals(unexpanded));
}
@Override
public boolean hasNext() {
return !q.isEmpty();
}
@Override
public CssValueNode next() {
advance();
return q.remove();
}
};
}
};
}
/**
* Use for debugging only.
*/
@Override
public String toString() {
return getValue();
}
}