org.apache.abdera2.common.templates.MultiContext.java Source code

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Here is the source code for org.apache.abdera2.common.templates.MultiContext.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  The ASF licenses this file to You
 * 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.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
package org.apache.abdera2.common.templates;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import com.google.common.base.Supplier;
import com.google.common.collect.ImmutableSet;

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

public final class MultiContext extends CachingContext {

    public static Builder make() {
        return new Builder();
    }

    public static final class Builder implements Supplier<Context> {

        final ImmutableSet.Builder<Context> contexts = ImmutableSet.builder();
        boolean isiri;

        public Builder iri() {
            this.isiri = false;
            return this;
        }

        public Builder with(Context context) {
            checkNotNull(context);
            this.contexts.add(context);
            return this;
        }

        @SuppressWarnings("unchecked")
        public Builder with(Object object) {
            checkNotNull(object);
            this.contexts.add(object instanceof Context ? (Context) object
                    : object instanceof Map ? new MapContext((Map<String, Object>) object)
                            : object instanceof Supplier ? new ObjectContext(((Supplier<?>) object).get())
                                    : new ObjectContext(object));
            return this;
        }

        public Context get() {
            return new MultiContext(this);
        }

    }

    private static final long serialVersionUID = 1691294411780004133L;
    private final Set<Context> contexts;

    MultiContext(Builder builder) {
        super(builder.isiri);
        this.contexts = builder.contexts.build();
    }

    public boolean contains(String var) {
        for (Context context : contexts)
            if (context.contains(var))
                return true;
        return false;
    }

    public Iterator<String> iterator() {
        ImmutableSet.Builder<String> names = ImmutableSet.builder();
        for (Context context : contexts)
            for (String name : context)
                names.add(name);
        return names.build().iterator();
    }

    protected <T> T resolveActual(String var) {
        for (Context context : contexts)
            if (context.contains(var))
                return context.<T>resolve(var);
        return null;
    }
}