org.mvel2.integration.impl.CachingMapVariableResolverFactory Maven / Gradle / Ivy

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/**
 * MVEL 2.0
 * Copyright (C) 2007 The Codehaus
 * Mike Brock, Dhanji Prasanna, John Graham, Mark Proctor
 *
 * 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 org.mvel2.integration.impl;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.mvel2.UnresolveablePropertyException;
import org.mvel2.integration.VariableResolver;

@SuppressWarnings({ "unchecked" })
public class CachingMapVariableResolverFactory extends BaseVariableResolverFactory {

    /**
     * Holds the instance of the variables.
     */
    protected Map variables;

    public CachingMapVariableResolverFactory(Map variables) {
        this.variables = variables;
    }

    public VariableResolver createVariable(String name, Object value) {
        VariableResolver vr;

        try {
            (vr = getVariableResolver(name)).setValue(value);
            return vr;
        } catch (UnresolveablePropertyException e) {
            addResolver(name, vr = new SimpleSTValueResolver(value, null, true));
            return vr;
        }
    }

    public VariableResolver createVariable(String name, Object value, Class type) {
        VariableResolver vr;
        try {
            vr = getVariableResolver(name);
        } catch (UnresolveablePropertyException e) {
            vr = null;
        }

        if (vr != null && vr.getType() != null) {
            throw new RuntimeException("variable already defined within scope: " + vr.getType() + " " + name);
        } else {
            addResolver(name, vr = new SimpleSTValueResolver(value, type, true));
            return vr;
        }
    }

    public VariableResolver getVariableResolver(String name) {
        VariableResolver vr = variableResolvers.get(name);
        if (vr != null) {
            return vr;
        } else if (variables.containsKey(name)) {
            variableResolvers.put(name, vr = new SimpleSTValueResolver(variables.get(name), null));
            return vr;
        } else if (nextFactory != null) {
            return nextFactory.getVariableResolver(name);
        }

        throw new UnresolveablePropertyException("unable to resolve variable '" + name + "'");
    }

    public boolean isResolveable(String name) {
        return (variableResolvers.containsKey(name)) || (variables != null && variables.containsKey(name))
                || (nextFactory != null && nextFactory.isResolveable(name));
    }

    protected VariableResolver addResolver(String name, VariableResolver vr) {
        variableResolvers.put(name, vr);
        return vr;
    }

    public void externalize() {
        for (Map.Entry entry : variableResolvers.entrySet()) {
            if (entry.getValue().getFlags() == -1) variables.put(entry.getKey(), entry.getValue().getValue());
        }
    }

    public boolean isTarget(String name) {
        return variableResolvers.containsKey(name);
    }

    public Set getKnownVariables() {
        if (nextFactory == null) {
            if (variables != null) return new HashSet(variables.keySet());
            return new HashSet(0);
        } else {
            if (variables != null) return new HashSet(variables.keySet());
            return new HashSet(0);
        }
    }

    public void clear() {
        variableResolvers.clear();
        variables.clear();
    }
}