com.google.template.soy.exprtree.ExprRootNode.java Source code

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Here is the source code for com.google.template.soy.exprtree.ExprRootNode.java

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/*
 * Copyright 2009 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.template.soy.exprtree;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.template.soy.basetree.CopyState;

import java.util.List;

/**
 * Dummy node that serves as the root of an expression tree so that the tree can be arbitrarily
 * changed without needing to change the reference to the tree.
 *
 * <p> Important: Do not use outside of Soy code (treat as superpackage-private).
 *
 * <p> This node should always have exactly one child.
 *
 */
public final class ExprRootNode extends AbstractParentExprNode {
    public static List<ExprNode> unwrap(Iterable<ExprRootNode> exprs) {
        ImmutableList.Builder<ExprNode> builder = ImmutableList.builder();
        for (ExprRootNode expr : exprs) {
            builder.add(expr.getRoot());
        }
        return builder.build();
    }

    public static List<ExprRootNode> wrap(Iterable<? extends ExprNode> exprs) {
        ImmutableList.Builder<ExprRootNode> builder = ImmutableList.builder();
        for (ExprNode expr : exprs) {
            builder.add(new ExprRootNode(expr));
        }
        return builder.build();
    }

    /**
     * Creates a new instance with the given node as the child.
     * @param child The child to add to the new node.
     */
    public ExprRootNode(ExprNode child) {
        super(child.getSourceLocation());
        checkArgument(!(child instanceof ExprRootNode));
        this.addChild(child);
    }

    /**
     * Copy constructor.
     * @param orig The node to copy.
     */
    private ExprRootNode(ExprRootNode orig, CopyState copyState) {
        super(orig, copyState);
    }

    @Override
    public Kind getKind() {
        return Kind.EXPR_ROOT_NODE;
    }

    public ExprNode getRoot() {
        return getChild(0);
    }

    @Override
    public ExprNode getChild(int index) {
        Preconditions.checkArgument(index == 0);
        return super.getChild(0);
    }

    @Override
    public String toSourceString() {
        return getRoot().toSourceString();
    }

    @Override
    public ExprRootNode copy(CopyState copyState) {
        return new ExprRootNode(this, copyState);
    }

}