Example usage for com.google.common.css.compiler.passes BooleanExpressionEvaluator evaluate

Introduction

In this page you can find the example usage for com.google.common.css.compiler.passes BooleanExpressionEvaluator evaluate.

Prototype

public CssBooleanExpressionNode evaluate() 

Source Link

Document

Evaluates the boolean expression associated with this evaluator.

Usage

From source file:com.google.gwt.resources.gss.ExtendedEliminateConditionalNodes.java

private boolean enterRuntimeConditionalBlock(CssConditionalBlockNode block) {
    boolean runtimeEvaluationNodeFound = false;
    List<CssConditionalRuleNode> newChildren = new ArrayList<CssConditionalRuleNode>(block.numChildren());

    for (CssConditionalRuleNode currentConditional : block.childIterable()) {
        if (currentConditional.getType() == Type.ELSE) {
            newChildren.add(currentConditional);
            break;
        }//from  w  w w .  ja  va  2  s. c  o m

        if (currentConditional instanceof CssRuntimeConditionalRuleNode) {
            runtimeEvaluationNodeFound = true;
            newChildren.add(currentConditional);
            continue;
        }

        // The node can be evaluated at compile time
        BooleanExpressionEvaluator evaluator = new BooleanExpressionEvaluator(currentConditional.getCondition(),
                trueConditions);

        CssBooleanExpressionNode result = evaluator.evaluate();
        boolean isTrue = CssBooleanExpressionNode.Type.TRUE_CONSTANT.equals(result.getValue());

        if (!isTrue) {
            // any node evaluated to false can be removed
        } else if (!runtimeEvaluationNodeFound) {
            // node evaluated to true before the runtime condition, replace the conditional block by the
            // children of this current conditional node.
            visitController.replaceCurrentBlockChildWith(currentConditional.getBlock().getChildren(), true);
            return true;
        } else {
            // node evaluated to true before the runtime condition, transform this node to an else node
            CssConditionalRuleNode newNode = new CssConditionalRuleNode(Type.ELSE, currentConditional.getName(),
                    null, currentConditional.getBlock());

            newChildren.add(newNode);
            break;
        }
    }

    CssConditionalBlockNode newNode = new CssConditionalBlockNode();
    for (CssConditionalRuleNode child : newChildren) {
        newNode.addChildToBack(child);
    }

    visitController.replaceCurrentBlockChildWith(Lists.newArrayList(newNode), true);

    // mark this node as already visited.
    alreadyTreatedNode.add(newNode);

    return true;
}

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