com.android.tools.idea.rendering.AttributeSnapshot.java Source code

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Here is the source code for com.android.tools.idea.rendering.AttributeSnapshot.java

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/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.android.tools.idea.rendering;

import com.android.tools.idea.databinding.DataBindingUtil;
import com.google.common.collect.Lists;
import com.intellij.psi.xml.XmlAttribute;
import com.intellij.psi.xml.XmlTag;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.List;

/**
 * A snapshot of an attribute value pulled from PSI. Used in conjunction with {@link TagSnapshot}.
 */
public class AttributeSnapshot {
    @Nullable
    public String namespace;
    @Nullable
    public String prefix;
    @NotNull
    public String name;
    @Nullable
    public String value;

    AttributeSnapshot(@Nullable String namespace, @Nullable String prefix, @NotNull String name,
            @Nullable String value) {
        this.namespace = namespace;
        this.prefix = prefix == null || prefix.isEmpty() ? null : prefix;
        this.name = name;
        this.value = value;
    }

    /**
     * Creates a snapshot of the given attribute.
     * <p>
     * NOTE: Returns null if the attribute should not be passed to LayoutLib.
     */
    @Nullable
    public static AttributeSnapshot createAttributeSnapshot(@NotNull XmlAttribute psiAttribute) {
        String localName = psiAttribute.getLocalName();
        String namespace = psiAttribute.getNamespace();
        String prefix = psiAttribute.getNamespacePrefix();
        String value = psiAttribute.getValue();
        if (value != null && DataBindingUtil.isBindingExpression(value)) {
            // if this is a binding expression, get the default value.
            value = DataBindingUtil.getBindingExprDefault(psiAttribute);
            if (value == null) {
                // If no default value, strip the attribute completely.
                return null;
            }
        }
        return new AttributeSnapshot(namespace, prefix, localName, value);
    }

    /** Creates a list of attribute snapshots corresponding to the attributes of the given tag */
    @NotNull
    public static List<AttributeSnapshot> createAttributesForTag(@NotNull XmlTag tag) {
        // Attributes
        XmlAttribute[] psiAttributes = tag.getAttributes();
        List<AttributeSnapshot> attributes = Lists.newArrayListWithExpectedSize(psiAttributes.length);
        for (XmlAttribute psiAttribute : psiAttributes) {
            AttributeSnapshot attribute = createAttributeSnapshot(psiAttribute);
            if (attribute != null) {
                attributes.add(attribute);
            }
        }

        return attributes;
    }

    @Override
    public String toString() {
        return "AttributeSnapshot{" + name + "=\"" + value + "\"}";
    }
}